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diff --git a/pod/perlglossary.pod b/pod/perlglossary.pod index e6985c6714..5befd5e175 100644 --- a/pod/perlglossary.pod +++ b/pod/perlglossary.pod @@ -15,22 +15,22 @@ L<http://catb.org/~esr/jargon/>, and Wikipedia L<http://www.wikipedia.org/>. =item accessor methods -A C<method> used to indirectly inspect or update an C<object>'s -state (its C<instance variable>s). +A L</method> used to indirectly inspect or update an L</object>'s +state (its L<instance variables|/instance variable>). =item actual arguments -The C<scalar value>s that you supply to a C<function> -or C<subroutine> when you call it. For instance, when you call +The L<scalar values|/scalar value> that you supply to a L</function> +or L</subroutine> when you call it. For instance, when you call C<power("puff")>, the string C<"puff"> is the actual argument. See -also C<argument> and C<formal arguments>. +also L</argument> and L</formal arguments>. =item address operator Some languages work directly with the memory addresses of values, but this can be like playing with fire. Perl provides a set of asbestos gloves for handling all memory management. The closest to an address -operator in Perl is the backslash operator, but it gives you a C<hard +operator in Perl is the backslash operator, but it gives you a L</hard reference>, which is much safer than a memory address. =item algorithm @@ -45,10 +45,10 @@ used the original name instead of the nickname. Temporary aliases are implicitly created in the loop variable for C<foreach> loops, in the C<$_> variable for L<map|perlfunc/map> or L<grep|perlfunc/grep> operators, in C<$a> and C<$b> during L<sort|perlfunc/sort>'s -comparison function, and in each element of C<@_> for the C<actual +comparison function, and in each element of C<@_> for the L</actual arguments> of a subroutine call. Permanent aliases are explicitly -created in C<package>s by C<import>ing symbols or by -assignment to C<typeglob>s. Lexically scoped aliases for +created in L<packages|/package> by L<importing|/import> symbols or by +assignment to L<typeglobs|/typeglob>. Lexically scoped aliases for package variables are explicitly created by the L<our|perlfunc/our> declaration. @@ -58,14 +58,14 @@ A list of possible choices from which you may select only one, as in "Would you like door A, B, or C?" Alternatives in regular expressions are separated with a single vertical bar: C<|>. Alternatives in normal Perl expressions are separated with a double vertical bar: -C<||>. Logical alternatives in C<Boolean> expressions are separated +C<||>. Logical alternatives in L</Boolean> expressions are separated with either C<||> or C<or>. =item anonymous -Used to describe a C<referent> that is not directly accessible -through a named C<variable>. Such a referent must be indirectly -accessible through at least one C<hard reference>. When the last +Used to describe a L</referent> that is not directly accessible +through a named L</variable>. Such a referent must be indirectly +accessible through at least one L</hard reference>. When the last hard reference goes away, the anonymous referent is destroyed without pity. @@ -76,37 +76,37 @@ means all those computers sharing a compatible machine language. Since Perl programs are (typically) simple text files, not executable images, a Perl program is much less sensitive to the architecture it's running on than programs in other languages, such as C, that are -compiled into machine code. See also C<platform> and C<operating +compiled into machine code. See also L</platform> and L</operating system>. =item argument A piece of data supplied to a L<program|/executable file>, -C<subroutine>, C<function>, or C<method> to tell it what it's +L</subroutine>, L</function>, or L</method> to tell it what it's supposed to do. Also called a "parameter". =item ARGV -The name of the array containing the C<argument> C<vector> from the -command line. If you use the empty C<E<lt>E<gt>> operator, C<ARGV> is -the name of both the C<filehandle> used to traverse the arguments and -the C<scalar> containing the name of the current input file. +The name of the array containing the L</argument> L</vector> from the +command line. If you use the empty C<< E<lt>E<gt> >> operator, L</ARGV> is +the name of both the L</filehandle> used to traverse the arguments and +the L</scalar> containing the name of the current input file. =item arithmetical operator -A C<symbol> such as C<+> or C</> that tells Perl to do the arithmetic +A L</symbol> such as C<+> or C</> that tells Perl to do the arithmetic you were supposed to learn in grade school. =item array -An ordered sequence of C<value>s, stored such that you can -easily access any of the values using an integer C<subscript> -that specifies the value's C<offset> in the sequence. +An ordered sequence of L<values|/value>, stored such that you can +easily access any of the values using an integer L</subscript> +that specifies the value's L</offset> in the sequence. =item array context An archaic expression for what is more correctly referred to as -C<list context>. +L</list context>. =item ASCII @@ -114,34 +114,34 @@ The American Standard Code for Information Interchange (a 7-bit character set adequate only for poorly representing English text). Often used loosely to describe the lowest 128 values of the various ISO-8859-X character sets, a bunch of mutually incompatible 8-bit -codes best described as half ASCII. See also C<Unicode>. +codes best described as half ASCII. See also L</Unicode>. =item assertion -A component of a C<regular expression> that must be true for the +A component of a L</regular expression> that must be true for the pattern to match but does not necessarily match any characters itself. -Often used specifically to mean a C<zero width> assertion. +Often used specifically to mean a L</zero width> assertion. =item assignment -An C<operator> whose assigned mission in life is to change the value -of a C<variable>. +An L</operator> whose assigned mission in life is to change the value +of a L</variable>. =item assignment operator -Either a regular C<assignment>, or a compound C<operator> composed +Either a regular L</assignment>, or a compound L</operator> composed of an ordinary assignment and some other operator, that changes the value of a variable in place, that is, relative to its old value. For example, C<$a += 2> adds C<2> to C<$a>. =item associative array -See C<hash>. Please. +See L</hash>. Please. =item associativity -Determines whether you do the left C<operator> first or the right -C<operator> first when you have "A C<operator> B C<operator> C" and +Determines whether you do the left L</operator> first or the right +L</operator> first when you have "A L</operator> B L</operator> C" and the two operators are of the same precedence. Operators like C<+> are left associative, while operators like C<**> are right associative. See L<perlop> for a list of operators and their associativity. @@ -154,10 +154,10 @@ asynchronous event is one you didn't know when to expect. =item atom -A C<regular expression> component potentially matching a -C<substring> containing one or more characters and treated as an -indivisible syntactic unit by any following C<quantifier>. (Contrast -with an C<assertion> that matches something of C<zero width> and may +A L</regular expression> component potentially matching a +L</substring> containing one or more characters and treated as an +indivisible syntactic unit by any following L</quantifier>. (Contrast +with an L</assertion> that matches something of L</zero width> and may not be quantified.) =item atomic operation @@ -169,15 +169,15 @@ can't be interrupted, not one forbidden in a nuclear-free zone. =item attribute -A new feature that allows the declaration of C<variable>s -and C<subroutine>s with modifiers as in C<sub foo : locked -method>. Also, another name for an C<instance variable> of an -C<object>. +A new feature that allows the declaration of L<variables|/variable> +and L<subroutines|/subroutine> with modifiers as in C<sub foo : locked +method>. Also, another name for an L</instance variable> of an +L</object>. =item autogeneration -A feature of C<operator overloading> of C<object>s, whereby -the behavior of certain C<operator>s can be reasonably +A feature of L</operator overloading> of L<objects|/object>, whereby +the behavior of certain L<operators|/operator> can be reasonably deduced using more fundamental operators. This assumes that the overloaded operators will often have the same relationships as the regular operators. See L<perlop>. @@ -191,20 +191,21 @@ known as an "autodecrement". =item autoload To load on demand. (Also called "lazy" loading.) Specifically, to -call an C<AUTOLOAD> subroutine on behalf of an undefined subroutine. +call an L<AUTOLOAD|perlsub/Autoloading> subroutine on behalf of an +undefined subroutine. =item autosplit -To split a string automatically, as the B<-a> C<switch> does when -running under B<-p> or B<-n> in order to emulate C<awk>. (See also -the C<AutoSplit> module, which has nothing to do with the B<-a> +To split a string automatically, as the B<-a> L</switch> does when +running under B<-p> or B<-n> in order to emulate L</awk>. (See also +the L<AutoSplit> module, which has nothing to do with the B<-a> switch, but a lot to do with autoloading.) =item autovivification A Greco-Roman word meaning "to bring oneself to life". In Perl, -storage locations (C<lvalue>s) spontaneously generate -themselves as needed, including the creation of any C<hard reference> +storage locations (L<lvalues|/lvalue>) spontaneously generate +themselves as needed, including the creation of any L</hard reference> values to point to the next level of storage. The assignment C<$a[5][5][5][5][5] = "quintet"> potentially creates five scalar storage locations, plus four references (in the first four scalar @@ -215,8 +216,8 @@ don't have to worry about it. =item AV Short for "array value", which refers to one of Perl's internal data -types that holds an C<array>. The C<AV> type is a subclass of -C<SV>. +types that holds an L</array>. The L</AV> type is a subclass of +L</SV>. =item awk @@ -233,7 +234,7 @@ some of its high-level ideas. =item backreference A substring L<captured|/capturing> by a subpattern within -unadorned parentheses in a C<regex>. Backslashed decimal numbers +unadorned parentheses in a L</regex>. Backslashed decimal numbers (C<\1>, C<\2>, etc.) later in the same pattern refer back to the corresponding subpattern in the current match. Outside the pattern, the numbered variables (C<$1>, C<$2>, etc.) continue to refer to these @@ -246,7 +247,7 @@ The practice of saying, "If I had to do it all over, I'd do it differently," and then actually going back and doing it all over differently. Mathematically speaking, it's returning from an unsuccessful recursion on a tree of possibilities. Perl backtracks -when it attempts to match patterns with a C<regular expression>, and +when it attempts to match patterns with a L</regular expression>, and its earlier attempts don't pan out. See L<perlre/Backtracking>. =item backward compatibility @@ -256,43 +257,43 @@ of the features or bugs it was relying on. =item bareword -A word sufficiently ambiguous to be deemed illegal under C<use strict -'subs'>. In the absence of that stricture, a bareword is treated as -if quotes were around it. +A word sufficiently ambiguous to be deemed illegal under L<use strict +'subs'|strict/strict subs>. In the absence of that stricture, a +bareword is treated as if quotes were around it. =item base class -A generic C<object> type; that is, a C<class> from which other, more -specific classes are derived genetically by C<inheritance>. Also +A generic L</object> type; that is, a L</class> from which other, more +specific classes are derived genetically by L</inheritance>. Also called a "superclass" by people who respect their ancestors. =item big-endian From Swift: someone who eats eggs big end first. Also used of -computers that store the most significant C<byte> of a word at a +computers that store the most significant L</byte> of a word at a lower byte address than the least significant byte. Often considered -superior to little-endian machines. See also C<little-endian>. +superior to little-endian machines. See also L</little-endian>. =item binary Having to do with numbers represented in base 2. That means there's basically two numbers, 0 and 1. Also used to describe a "non-text file", presumably because such a file makes full use of all the binary -bits in its bytes. With the advent of C<Unicode>, this distinction, +bits in its bytes. With the advent of L</Unicode>, this distinction, already suspect, loses even more of its meaning. =item binary operator -An C<operator> that takes two C<operand>s. +An L</operator> that takes two L<operands|/operand>. =item bind -To assign a specific C<network address> to a C<socket>. +To assign a specific L</network address> to a L</socket>. =item bit An integer in the range from 0 to 1, inclusive. The smallest possible -unit of information storage. An eighth of a C<byte> or of a dollar. +unit of information storage. An eighth of a L</byte> or of a dollar. (The term "Pieces of Eight" comes from being able to split the old Spanish dollar into 8 bits, each of which still counted for money. That's why a 25-cent piece today is still "two bits".) @@ -304,51 +305,51 @@ effect of multiplying or dividing by a power of 2. =item bit string -A sequence of C<bit>s that is actually being thought of as a +A sequence of L<bits|/bit> that is actually being thought of as a sequence of bits, for once. =item bless In corporate life, to grant official approval to a thing, as in, "The VP of Engineering has blessed our WebCruncher project." Similarly in -Perl, to grant official approval to a C<referent> so that it can -function as an C<object>, such as a WebCruncher object. See +Perl, to grant official approval to a L</referent> so that it can +function as an L</object>, such as a WebCruncher object. See L<perlfunc/"bless">. =item block -What a C<process> does when it has to wait for something: "My process +What a L</process> does when it has to wait for something: "My process blocked waiting for the disk." As an unrelated noun, it refers to a -large chunk of data, of a size that the C<operating system> likes to +large chunk of data, of a size that the L</operating system> likes to deal with (normally a power of two such as 512 or 8192). Typically refers to a chunk of data that's coming from or going to a disk file. =item BLOCK A syntactic construct consisting of a sequence of Perl -C<statement>s that is delimited by braces. The C<if> and -C<while> statements are defined in terms of C<BLOCK>s, for instance. +L<statements|/statement> that is delimited by braces. The C<if> and +C<while> statements are defined in terms of L<BLOCKs|/BLOCK>, for instance. Sometimes we also say "block" to mean a lexical scope; that is, a -sequence of statements that act like a C<BLOCK>, such as within an +sequence of statements that act like a L</BLOCK>, such as within an L<eval|perlfunc/eval> or a file, even though the statements aren't delimited by braces. =item block buffering -A method of making input and output efficient by passing one C<block> +A method of making input and output efficient by passing one L</block> at a time. By default, Perl does block buffering to disk files. See -C<buffer> and C<command buffering>. +L</buffer> and L</command buffering>. =item Boolean -A value that is either C<true> or C<false>. +A value that is either L</true> or L</false>. =item Boolean context -A special kind of C<scalar context> used in conditionals to decide -whether the C<scalar value> returned by an expression is C<true> or -C<false>. Does not evaluate as either a string or a number. See -C<context>. +A special kind of L</scalar context> used in conditionals to decide +whether the L</scalar value> returned by an expression is L</true> or +L</false>. Does not evaluate as either a string or a number. See +L</context>. =item breakpoint @@ -358,7 +359,7 @@ is wrong yet. =item broadcast -To send a C<datagram> to multiple destinations simultaneously. +To send a L</datagram> to multiple destinations simultaneously. =item BSD @@ -370,40 +371,41 @@ useful. (Or, at least, more fun.) The full chemical name is =item bucket -A location in a C<hash table> containing (potentially) multiple +A location in a L</hash table> containing (potentially) multiple entries whose keys "hash" to the same hash value according to its hash function. (As internal policy, you don't have to worry about it, unless you're into internals, or policy.) =item buffer -A temporary holding location for data. With C<block buffering>, the -data is passed on to its destination whenever the buffer is full. -With C<line buffering>, it's passed on whenever a complete line is -received. With C<command buffering>, it's passed every time you do a -L<print|perlfunc/print> command (or equivalent). If your output is +A temporary holding location for data. L<Block buffering|/block +buffering> means that the data is passed on to its destination +whenever the buffer is full. L<Line buffering|/line buffering> means +that it's passed on whenever a complete line is received. L<Command +buffering|/command buffering> means that it's passed every time you do +a L<print|perlfunc/print> command (or equivalent). If your output is unbuffered, the system processes it one byte at a time without the use of a holding area. This can be rather inefficient. =item built-in -A C<function> that is predefined in the language. Even when hidden -by C<overriding>, you can always get at a built-in function by +A L</function> that is predefined in the language. Even when hidden +by L</overriding>, you can always get at a built-in function by L<qualifying|/qualified> its name with the C<CORE::> pseudo-package. =item bundle -A group of related modules on C<CPAN>. (Also, sometimes refers to a -group of command-line switches grouped into one C<switch cluster>.) +A group of related modules on L</CPAN>. (Also, sometimes refers to a +group of command-line switches grouped into one L</switch cluster>.) =item byte -A piece of data worth eight C<bit>s in most places. +A piece of data worth eight L<bits|/bit> in most places. =item bytecode A pidgin-like language spoken among 'droids when they don't wish to -reveal their orientation (see C<endian>). Named after some similar +reveal their orientation (see L</endian>). Named after some similar languages spoken (for similar reasons) between compilers and interpreters in the late 20th century. These languages are characterized by representing everything as a @@ -417,8 +419,8 @@ non-architecture-dependent sequence of bytes. =item C -A language beloved by many for its inside-out C<type> definitions, -inscrutable C<precedence> rules, and heavy C<overloading> of the +A language beloved by many for its inside-out L</type> definitions, +inscrutable L</precedence> rules, and heavy L</overloading> of the function-call mechanism. (Well, actually, people first switched to C because they found lowercase identifiers easier to read than upper.) Perl is written in C, so it's not surprising that Perl borrowed a few @@ -433,23 +435,23 @@ definitions. Also known as I<cpp>(1). =item call by reference -An C<argument>-passing mechanism in which the C<formal arguments> -refer directly to the C<actual arguments>, and the C<subroutine> can +An L</argument>-passing mechanism in which the L</formal arguments> +refer directly to the L</actual arguments>, and the L</subroutine> can change the actual arguments by changing the formal arguments. That -is, the formal argument is an C<alias> for the actual argument. See -also C<call by value>. +is, the formal argument is an L</alias> for the actual argument. See +also L</call by value>. =item call by value -An C<argument>-passing mechanism in which the C<formal arguments> -refer to a copy of the C<actual arguments>, and the C<subroutine> +An L</argument>-passing mechanism in which the L</formal arguments> +refer to a copy of the L</actual arguments>, and the L</subroutine> cannot change the actual arguments by changing the formal arguments. -See also C<call by reference>. +See also L</call by reference>. =item callback -A C<handler> that you register with some other part of your program -in the hope that the other part of your program will C<trigger> your +A L</handler> that you register with some other part of your program +in the hope that the other part of your program will L</trigger> your handler when some event of interest transpires. =item canonical @@ -458,9 +460,9 @@ Reduced to a standard form to facilitate comparison. =item capturing -The use of parentheses around a C<subpattern> in a C<regular -expression> to store the matched C<substring> as a C<backreference>. -(Captured strings are also returned as a list in C<list context>.) +The use of parentheses around a L</subpattern> in a L</regular +expression> to store the matched L</substring> as a L</backreference>. +(Captured strings are also returned as a list in L</list context>.) =item character @@ -474,108 +476,108 @@ for the most part. =item character class -A square-bracketed list of characters used in a C<regular expression> +A square-bracketed list of characters used in a L</regular expression> to indicate that any character of the set may occur at a given point. Loosely, any predefined set of characters so used. =item character property -A predefined C<character class> matchable by the C<\p> -C<metasymbol>. Many standard properties are defined for C<Unicode>. +A predefined L</character class> matchable by the C<\p> +L</metasymbol>. Many standard properties are defined for L</Unicode>. =item circumfix operator -An C<operator> that surrounds its C<operand>, like the angle +An L</operator> that surrounds its L</operand>, like the angle operator, or parentheses, or a hug. =item class -A user-defined C<type>, implemented in Perl via a C<package> that -provides (either directly or by inheritance) C<method>s (that -is, C<subroutine>s) to handle C<instance>s of -the class (its C<object>s). See also C<inheritance>. +A user-defined L</type>, implemented in Perl via a L</package> that +provides (either directly or by inheritance) L<methods|/method> (that +is, L<subroutines|/subroutine>) to handle L<instances|/instance> of +the class (its L<objects|/object>). See also L</inheritance>. =item class method -A C<method> whose C<invocant> is a C<package> name, not an -C<object> reference. A method associated with the class as a whole. +A L</method> whose L</invocant> is a L</package> name, not an +L</object> reference. A method associated with the class as a whole. =item client -In networking, a C<process> that initiates contact with a C<server> +In networking, a L</process> that initiates contact with a L</server> process in order to exchange data and perhaps receive a service. =item cloister -A C<cluster> used to restrict the scope of a C<regular expression +A L</cluster> used to restrict the scope of a L</regular expression modifier>. =item closure -An C<anonymous> subroutine that, when a reference to it is generated +An L</anonymous> subroutine that, when a reference to it is generated at run time, keeps track of the identities of externally visible -C<lexical variable>s even after those lexical -variables have supposedly gone out of C<scope>. They're called +L<lexical variables|/lexical variable> even after those lexical +variables have supposedly gone out of L</scope>. They're called "closures" because this sort of behavior gives mathematicians a sense of closure. =item cluster -A parenthesized C<subpattern> used to group parts of a C<regular -expression> into a single C<atom>. +A parenthesized L</subpattern> used to group parts of a L</regular +expression> into a single L</atom>. =item CODE The word returned by the L<ref|perlfunc/ref> function when you apply -it to a reference to a subroutine. See also C<CV>. +it to a reference to a subroutine. See also L</CV>. =item code generator A system that writes code for you in a low-level language, such as -code to implement the backend of a compiler. See C<program +code to implement the backend of a compiler. See L</program generator>. =item code subpattern -A C<regular expression> subpattern whose real purpose is to execute +A L</regular expression> subpattern whose real purpose is to execute some Perl code, for example, the C<(?{...})> and C<(??{...})> subpatterns. =item collating sequence -The order into which C<character>s sort. This is used by -C<string> comparison routines to decide, for example, where in this +The order into which L<characters|/character> sort. This is used by +L</string> comparison routines to decide, for example, where in this glossary to put "collating sequence". =item command -In C<shell> programming, the syntactic combination of a program name +In L</shell> programming, the syntactic combination of a program name and its arguments. More loosely, anything you type to a shell (a command interpreter) that starts it doing something. Even more -loosely, a Perl C<statement>, which might start with a C<label> and +loosely, a Perl L</statement>, which might start with a L</label> and typically ends with a semicolon. =item command buffering A mechanism in Perl that lets you store up the output of each Perl -C<command> and then flush it out as a single request to the -C<operating system>. It's enabled by setting the C<$|> +L</command> and then flush it out as a single request to the +L</operating system>. It's enabled by setting the C<$|> (C<$AUTOFLUSH>) variable to a true value. It's used when you don't want data sitting around not going where it's supposed to, which may -happen because the default on a C<file> or C<pipe> is to use -C<block buffering>. +happen because the default on a L</file> or L</pipe> is to use +L</block buffering>. =item command name The name of the program currently executing, as typed on the command -line. In C, the C<command> name is passed to the program as the +line. In C, the L</command> name is passed to the program as the first command-line argument. In Perl, it comes in separately as C<$0>. =item command-line arguments -The C<value>s you supply along with a program name when you -tell a C<shell> to execute a C<command>. These values are passed to +The L<values|/value> you supply along with a program name when you +tell a L</shell> to execute a L</command>. These values are passed to a Perl program through C<@ARGV>. =item comment @@ -586,14 +588,14 @@ the line. =item compilation unit -The C<file> (or C<string>, in the case of L<eval|perlfunc/eval>) +The L</file> (or L</string>, in the case of L<eval|perlfunc/eval>) that is currently being compiled. =item compile phase Any time before Perl starts running your main program. See also -C<run phase>. Compile phase is mostly spent in C<compile time>, but -may also be spent in C<run time> when C<BEGIN> blocks, +L</run phase>. Compile phase is mostly spent in L</compile time>, but +may also be spent in L</run time> when C<BEGIN> blocks, L<use|perlfunc/use> declarations, or constant subexpressions are being evaluated. The startup and import code of any L<use|perlfunc/use> declaration is also run during compile phase. @@ -602,7 +604,7 @@ declaration is also run during compile phase. The time when Perl is trying to make sense of your code, as opposed to when it thinks it knows what your code means and is merely trying to -do what it thinks your code says to do, which is C<run time>. +do what it thinks your code says to do, which is L</run time>. =item compiler @@ -611,14 +613,14 @@ out yet another file containing the program in a "more executable" form, typically containing native machine instructions. The I<perl> program is not a compiler by this definition, but it does contain a kind of compiler that takes a program and turns it into a more -executable form (C<syntax tree>s) within the I<perl> -process itself, which the C<interpreter> then interprets. There are, -however, extension C<module>s to get Perl to act more like a +executable form (L<syntax trees|/syntax tree>) within the I<perl> +process itself, which the L</interpreter> then interprets. There are, +however, extension L<modules|/module> to get Perl to act more like a "real" compiler. See L<O>. =item composer -A "constructor" for a C<referent> that isn't really an C<object>, +A "constructor" for a L</referent> that isn't really an L</object>, like an anonymous array or a hash (or a sonata, for that matter). For example, a pair of braces acts as a composer for a hash, and a pair of brackets acts as a composer for an array. See L<perlref/Making @@ -627,53 +629,53 @@ References>. =item concatenation The process of gluing one cat's nose to another cat's tail. Also, a -similar operation on two C<string>s. +similar operation on two L<strings|/string>. =item conditional -Something "iffy". See C<Boolean context>. +Something "iffy". See L</Boolean context>. =item connection In telephony, the temporary electrical circuit between the caller's and the callee's phone. In networking, the same kind of temporary -circuit between a C<client> and a C<server>. +circuit between a L</client> and a L</server>. =item construct As a noun, a piece of syntax made up of smaller pieces. As a -transitive verb, to create an C<object> using a C<constructor>. +transitive verb, to create an L</object> using a L</constructor>. =item constructor -Any C<class method>, instance C<method>, or C<subroutine> -that composes, initializes, blesses, and returns an C<object>. -Sometimes we use the term loosely to mean a C<composer>. +Any L</class method>, instance L</method>, or L</subroutine> +that composes, initializes, blesses, and returns an L</object>. +Sometimes we use the term loosely to mean a L</composer>. =item context The surroundings, or environment. The context given by the surrounding code determines what kind of data a particular -C<expression> is expected to return. The three primary contexts are -C<list context>, C<scalar context>, and C<void context>. Scalar -context is sometimes subdivided into C<Boolean context>, C<numeric -context>, C<string context>, and C<void context>. There's also a +L</expression> is expected to return. The three primary contexts are +L</list context>, L</scalar context>, and L</void context>. Scalar +context is sometimes subdivided into L</Boolean context>, L</numeric +context>, L</string context>, and L</void context>. There's also a "don't care" scalar context (which is dealt with in Programming Perl, Third Edition, Chapter 2, "Bits and Pieces" if you care). =item continuation -The treatment of more than one physical C<line> as a single logical -line. C<Makefile> lines are continued by putting a backslash before -the C<newline>. Mail headers as defined by RFC 822 are continued by +The treatment of more than one physical L</line> as a single logical +line. L</Makefile> lines are continued by putting a backslash before +the L</newline>. Mail headers as defined by RFC 822 are continued by putting a space or tab I<after> the newline. In general, lines in -Perl do not need any form of continuation mark, because C<whitespace> +Perl do not need any form of continuation mark, because L</whitespace> (including newlines) is gleefully ignored. Usually. =item core dump -The corpse of a C<process>, in the form of a file left in the -C<working directory> of the process, usually as a result of certain +The corpse of a L</process>, in the form of a file left in the +L</working directory> of the process, usually as a result of certain kinds of fatal error. =item CPAN @@ -683,28 +685,29 @@ The Comprehensive Perl Archive Network. (See L<perlfaq2/What modules and extens =item cracker Someone who breaks security on computer systems. A cracker may be a -true C<hacker> or only a C<script kiddie>. +true L</hacker> or only a L</script kiddie>. =item current package -The C<package> in which the current statement is compiled. Scan +The L</package> in which the current statement is compiled. Scan backwards in the text of your program through the current L<lexical scope|/lexical scoping> or any enclosing lexical scopes till you find a package declaration. That's your current package name. =item current working directory -See C<working directory>. +See L</working directory>. =item currently selected output channel -The last C<filehandle> that was designated with -C<select(FILEHANDLE)>; C<STDOUT>, if no filehandle has been selected. +The last L</filehandle> that was designated with +L<select|perlfunc/select>(C<FILEHANDLE>); L</STDOUT>, if no filehandle +has been selected. =item CV -An internal "code value" typedef, holding a C<subroutine>. The C<CV> -type is a subclass of C<SV>. +An internal "code value" typedef, holding a L</subroutine>. The L</CV> +type is a subclass of L</SV>. =back @@ -714,7 +717,7 @@ type is a subclass of C<SV>. =item dangling statement -A bare, single C<statement>, without any braces, hanging off an C<if> +A bare, single L</statement>, without any braces, hanging off an C<if> or C<while> conditional. C allows them. Perl doesn't. =item data structure @@ -730,38 +733,38 @@ how to deal with those values. For example, a numeric data type has a certain set of numbers that you can work with and various mathematical operations that you can do on the numbers but would make little sense on, say, a string such as C<"Kilroy">. Strings have their own -operations, such as C<concatenation>. Compound types made of a +operations, such as L</concatenation>. Compound types made of a number of smaller pieces generally have operations to compose and -decompose them, and perhaps to rearrange them. An C<object> -that models things in the real world often has operations that +decompose them, and perhaps to rearrange them. L<Objects|/object> +that model things in the real world often have operations that correspond to real activities. For instance, if you model an elevator, your elevator object might have an C<open_door()> -C<method>. +L</method>. =item datagram -A packet of data, such as a C<UDP> message, that (from the viewpoint +A packet of data, such as a L</UDP> message, that (from the viewpoint of the programs involved) can be sent independently over the network. -(In fact, all packets are sent independently at the C<IP> level, but -C<stream> protocols such as C<TCP> hide this from your program.) +(In fact, all packets are sent independently at the L</IP> level, but +L</stream> protocols such as L</TCP> hide this from your program.) =item DBM Stands for "Data Base Management" routines, a set of routines that -emulate an C<associative array> using disk files. The routines use a +emulate an L</associative array> using disk files. The routines use a dynamic hashing scheme to locate any entry with only two disk accesses. DBM files allow a Perl program to keep a persistent -C<hash> across multiple invocations. You can L<tie|perlfunc/tie> +L</hash> across multiple invocations. You can L<tie|perlfunc/tie> your hash variables to various DBM implementations--see L<AnyDBM_File> and L<DB_File>. =item declaration -An C<assertion> that states something exists and perhaps describes +An L</assertion> that states something exists and perhaps describes what it's like, without giving any commitment as to how or where you'll use it. A declaration is like the part of your recipe that says, "two cups flour, one large egg, four or five tadpoles..." See -C<statement> for its opposite. Note that some declarations also +L</statement> for its opposite. Note that some declarations also function as statements. Subroutine declarations also act as definitions if a body is supplied. @@ -772,65 +775,65 @@ to remove 1 from its value) or "decrement C<$x> by 3". =item default -A C<value> chosen for you if you don't supply a value of your own. +A L</value> chosen for you if you don't supply a value of your own. =item defined Having a meaning. Perl thinks that some of the things people try to do are devoid of meaning, in particular, making use of variables that -have never been given a C<value> and performing certain operations on +have never been given a L</value> and performing certain operations on data that isn't there. For example, if you try to read data past the end of a file, Perl will hand you back an undefined value. See also -C<false> and L<perlfunc/defined>. +L</false> and L<perlfunc/defined>. =item delimiter -A C<character> or C<string> that sets bounds to an arbitrarily-sized -textual object, not to be confused with a C<separator> or -C<terminator>. "To delimit" really just means "to surround" or "to +A L</character> or L</string> that sets bounds to an arbitrarily-sized +textual object, not to be confused with a L</separator> or +L</terminator>. "To delimit" really just means "to surround" or "to enclose" (like these parentheses are doing). =item dereference -A fancy computer science term meaning "to follow a C<reference> to +A fancy computer science term meaning "to follow a L</reference> to what it points to". The "de" part of it refers to the fact that -you're taking away one level of C<indirection>. +you're taking away one level of L</indirection>. =item derived class -A C<class> that defines some of its C<method>s in terms of a -more generic class, called a C<base class>. Note that classes aren't +A L</class> that defines some of its L<methods|/method> in terms of a +more generic class, called a L</base class>. Note that classes aren't classified exclusively into base classes or derived classes: a class can function as both a derived class and a base class simultaneously, which is kind of classy. =item descriptor -See C<file descriptor>. +See L</file descriptor>. =item destroy -To deallocate the memory of a C<referent> (first triggering its +To deallocate the memory of a L</referent> (first triggering its C<DESTROY> method, if it has one). =item destructor -A special C<method> that is called when an C<object> is thinking -about C<destroy>ing itself. A Perl program's C<DESTROY> +A special L</method> that is called when an L</object> is thinking +about L<destroying|/destroy> itself. A Perl program's C<DESTROY> method doesn't do the actual destruction; Perl just -C<trigger>s the method in case the C<class> wants to do any +L<triggers|/trigger> the method in case the L</class> wants to do any associated cleanup. =item device A whiz-bang hardware gizmo (like a disk or tape drive or a modem or a -joystick or a mouse) attached to your computer, that the C<operating -system> tries to make look like a C<file> (or a bunch of files). +joystick or a mouse) attached to your computer, that the L</operating +system> tries to make look like a L</file> (or a bunch of files). Under Unix, these fake files tend to live in the I</dev> directory. =item directive -A C<pod> directive. See L<perlpod>. +A L</pod> directive. See L<perlpod>. =item directory @@ -849,8 +852,8 @@ function. To send something to its correct destination. Often used metaphorically to indicate a transfer of programmatic control to a destination selected algorithmically, often by lookup in a table of -function C<reference>s or, in the case of object -C<method>s, by traversing the inheritance tree looking for the +function L<references|/reference> or, in the case of object +L<methods|/method>, by traversing the inheritance tree looking for the most specific definition for the method. =item distribution @@ -862,7 +865,7 @@ will be called a "binary-only" distribution. =item dweomer An enchantment, illusion, phantasm, or jugglery. Said when Perl's -magical C<dwimmer> effects don't do what you expect, but rather seem +magical L</dwimmer> effects don't do what you expect, but rather seem to be the product of arcane dweomercraft, sorcery, or wonder working. [From Old English] @@ -872,18 +875,18 @@ DWIM is an acronym for "Do What I Mean", the principle that something should just do what you want it to do without an undue amount of fuss. A bit of code that does "dwimming" is a "dwimmer". Dwimming can require a great deal of behind-the-scenes magic, which (if it doesn't -stay properly behind the scenes) is called a C<dweomer> instead. +stay properly behind the scenes) is called a L</dweomer> instead. =item dynamic scoping Dynamic scoping works over a dynamic scope, making variables visible -throughout the rest of the C<block> in which they are first used and -in any C<subroutine>s that are called by the rest of the +throughout the rest of the L</block> in which they are first used and +in any L<subroutines|/subroutine> that are called by the rest of the block. Dynamically scoped variables can have their values temporarily changed (and implicitly restored later) by a L<local|perlfunc/local> -operator. (Compare C<lexical scoping>.) Used more loosely to mean +operator. (Compare L</lexical scoping>.) Used more loosely to mean how a subroutine that is in the middle of calling another subroutine -"contains" that subroutine at C<run time>. +"contains" that subroutine at L</run time>. =back @@ -897,7 +900,7 @@ Derived from many sources. Some would say I<too> many. =item element -A basic building block. When you're talking about an C<array>, it's +A basic building block. When you're talking about an L</array>, it's one of the items that make up the array. =item embedding @@ -908,59 +911,59 @@ interpreter in my editor!" =item empty subclass test -The notion that an empty C<derived class> should behave exactly like -its C<base class>. +The notion that an empty L</derived class> should behave exactly like +its L</base class>. =item en passant -When you change a C<value> as it is being copied. [From French, "in +When you change a L</value> as it is being copied. [From French, "in passing", as in the exotic pawn-capturing maneuver in chess.] =item encapsulation -The veil of abstraction separating the C<interface> from the -C<implementation> (whether enforced or not), which mandates that all -access to an C<object>'s state be through C<method>s alone. +The veil of abstraction separating the L</interface> from the +L</implementation> (whether enforced or not), which mandates that all +access to an L</object>'s state be through L<methods|/method> alone. =item endian -See C<little-endian> and C<big-endian>. +See L</little-endian> and L</big-endian>. =item environment -The collective set of C<environment variable>s -your C<process> inherits from its parent. Accessed via C<%ENV>. +The collective set of L<environment variables|/environment variable> +your L</process> inherits from its parent. Accessed via C<%ENV>. =item environment variable A mechanism by which some high-level agent such as a user can pass its -preferences down to its future offspring (child C<process>es, +preferences down to its future offspring (child L<processes|/process>, grandchild processes, great-grandchild processes, and so on). Each -environment variable is a C<key>/C<value> pair, like one entry in a -C<hash>. +environment variable is a L</key>/L</value> pair, like one entry in a +L</hash>. =item EOF End of File. Sometimes used metaphorically as the terminating string -of a C<here document>. +of a L</here document>. =item errno -The error number returned by a C<syscall> when it fails. Perl refers +The error number returned by a L</syscall> when it fails. Perl refers to the error by the name C<$!> (or C<$OS_ERROR> if you use the English module). =item error -See C<exception> or C<fatal error>. +See L</exception> or L</fatal error>. =item escape sequence -See C<metasymbol>. +See L</metasymbol>. =item exception -A fancy term for an error. See C<fatal error>. +A fancy term for an error. See L</fatal error>. =item exception handling @@ -969,21 +972,21 @@ mechanism in Perl is the L<eval|perlfunc/eval> operator. =item exec -To throw away the current C<process>'s program and replace it with +To throw away the current L</process>'s program and replace it with another without exiting the process or relinquishing any resources held (apart from the old memory image). =item executable file -A C<file> that is specially marked to tell the C<operating system> +A L</file> that is specially marked to tell the L</operating system> that it's okay to run this file as a program. Usually shortened to "executable". =item execute -To run a L<program|/executable file> or C<subroutine>. (Has nothing +To run a L<program|/executable file> or L</subroutine>. (Has nothing to do with the L<kill|perlfunc/kill> built-in, unless you're trying to -run a C<signal handler>.) +run a L</signal handler>.) =item execute bit @@ -994,17 +997,17 @@ collectively, or not at all. =item exit status -See C<status>. +See L</status>. =item export -To make symbols from a C<module> available for C<import> by other modules. +To make symbols from a L</module> available for L</import> by other modules. =item expression -Anything you can legally say in a spot where a C<value> is required. -Typically composed of C<literal>s, C<variable>s, -C<operator>s, C<function>s, and C<subroutine> +Anything you can legally say in a spot where a L</value> is required. +Typically composed of L<literals|/literal>, L<variables|/variable>, +L<operators|/operator>, L<functions|/function>, and L</subroutine> calls, not necessarily in that order. =item extension @@ -1033,8 +1036,8 @@ standard with Perl). =item fatal error -An uncaught C<exception>, which causes termination of the C<process> -after printing a message on your C<standard error> stream. Errors +An uncaught L</exception>, which causes termination of the L</process> +after printing a message on your L</standard error> stream. Errors that happen inside an L<eval|perlfunc/eval> are not fatal. Instead, the L<eval|perlfunc/eval> terminates after placing the exception message in the C<$@> (C<$EVAL_ERROR>) variable. You can try to @@ -1046,41 +1049,41 @@ L<die|perlfunc/die> becomes a fatal error. =item field A single piece of numeric or string data that is part of a longer -C<string>, C<record>, or C<line>. Variable-width fields are -usually split up by C<separator>s (so use -L<split|perlfunc/split> to extract the fields), while fixed-width -fields are usually at fixed positions (so use -L<unpack|perlfunc/unpack>). "fields" are also called C<instance variable>s. +L</string>, L</record>, or L</line>. Variable-width fields are usually +split up by L<separators|/separator> (so use L<split|perlfunc/split> to +extract the fields), while fixed-width fields are usually at fixed +positions (so use L<unpack|perlfunc/unpack>). L<Instance +variables|/instance variable> are also known as fields. =item FIFO -First In, First Out. See also C<LIFO>. Also, a nickname for a -C<named pipe>. +First In, First Out. See also L</LIFO>. Also, a nickname for a +L</named pipe>. =item file -A named collection of data, usually stored on disk in a C<directory> -in a C<filesystem>. Roughly like a document, if you're into office +A named collection of data, usually stored on disk in a L</directory> +in a L</filesystem>. Roughly like a document, if you're into office metaphors. In modern filesystems, you can actually give a file more than one name. Some files have special properties, like directories and devices. =item file descriptor -The little number the C<operating system> uses to keep track of which -opened C<file> you're talking about. Perl hides the file descriptor -inside a C<standard IE<sol>O> stream and then attaches the stream to -a C<filehandle>. +The little number the L</operating system> uses to keep track of which +opened L</file> you're talking about. Perl hides the file descriptor +inside a L</standard IE<sol>O> stream and then attaches the stream to +a L</filehandle>. =item file test operator A built-in unary operator that you use to determine whether something -is C<true> about a file, such as C<-o $filename> to test whether +is L</true> about a file, such as C<-o $filename> to test whether you're the owner of the file. =item fileglob -A "wildcard" match on C<filename>s. See the +A "wildcard" match on L<filenames|/filename>. See the L<glob|perlfunc/glob> function. =item filehandle @@ -1094,15 +1097,15 @@ each file. =item filename -One name for a file. This name is listed in a C<directory>, and you -can use it in an L<open|perlfunc/open> to tell the C<operating +One name for a file. This name is listed in a L</directory>, and you +can use it in an L<open|perlfunc/open> to tell the L</operating system> exactly which file you want to open, and associate the file -with a C<filehandle> which will carry the subsequent identity of that +with a L</filehandle> which will carry the subsequent identity of that file in your program, until you close it. =item filesystem -A set of L<directories|/directory> and C<file>s residing on a +A set of L<directories|/directory> and L<files|/file> residing on a partition of the disk. Sometimes known as a "partition". You can change the file's name or even move a file around from directory to directory within a filesystem without actually moving the file itself, @@ -1110,13 +1113,13 @@ at least under Unix. =item filter -A program designed to take a C<stream> of input and transform it into +A program designed to take a L</stream> of input and transform it into a stream of output. =item flag We tend to avoid this term because it means so many things. It may -mean a command-line C<switch> that takes no argument +mean a command-line L</switch> that takes no argument itself (such as Perl's B<-n> and B<-p> flags) or, less frequently, a single-bit indicator (such as the C<O_CREAT> and C<O_EXCL> flags used in @@ -1128,35 +1131,35 @@ A method of storing numbers in "scientific notation", such that the precision of the number is independent of its magnitude (the decimal point "floats"). Perl does its numeric work with floating-point numbers (sometimes called "floats"), when it can't get away with -using C<integer>s. Floating-point numbers are mere +using L<integers|/integer>. Floating-point numbers are mere approximations of real numbers. =item flush -The act of emptying a C<buffer>, often before it's full. +The act of emptying a L</buffer>, often before it's full. =item FMTEYEWTK Far More Than Everything You Ever Wanted To Know. An exhaustive -treatise on one narrow topic, something of a super-C<FAQ>. See Tom +treatise on one narrow topic, something of a super-L</FAQ>. See Tom for far more. =item fork -To create a child C<process> identical to the parent process at its +To create a child L</process> identical to the parent process at its moment of conception, at least until it gets ideas of its own. A thread with protected memory. =item formal arguments -The generic names by which a C<subroutine> knows its -C<argument>s. In many languages, formal arguments are +The generic names by which a L</subroutine> knows its +L<arguments|/argument>. In many languages, formal arguments are always given individual names, but in Perl, the formal arguments are just the elements of an array. The formal arguments to a Perl program are C<$ARGV[0]>, C<$ARGV[1]>, and so on. Similarly, the formal arguments to a Perl subroutine are C<$_[0]>, C<$_[1]>, and so on. You may give the arguments individual names by assigning the values to a -L<my|perlfunc/my> list. See also C<actual arguments>. +L<my|perlfunc/my> list. See also L</actual arguments>. =item format @@ -1179,16 +1182,16 @@ a copy to all your friends. Historically, any software that you give away, particularly if you make the source code available as well. Now often called C<open source software>. Recently there has been a trend to use the term in -contradistinction to C<open source software>, to refer only to free +contradistinction to L</open source software>, to refer only to free software released under the Free Software Foundation's GPL (General Public License), but this is difficult to justify etymologically. =item function Mathematically, a mapping of each of a set of input values to a -particular output value. In computers, refers to a C<subroutine> or -C<operator> that returns a C<value>. It may or may not have input -values (called C<argument>s). +particular output value. In computers, refers to a L</subroutine> or +L</operator> that returns a L</value>. It may or may not have input +values (called L<arguments|/argument>). =item funny character @@ -1215,30 +1218,30 @@ circular references and such.) =item GID -Group ID--in Unix, the numeric group ID that the C<operating system> -uses to identify you and members of your C<group>. +Group ID--in Unix, the numeric group ID that the L</operating system> +uses to identify you and members of your L</group>. =item glob Strictly, the shell's C<*> character, which will match a "glob" of characters when you're trying to generate a list of filenames. Loosely, the act of using globs and similar symbols to do pattern -matching. See also C<fileglob> and C<typeglob>. +matching. See also L</fileglob> and L</typeglob>. =item global Something you can see from anywhere, usually used of -C<variable>s and C<subroutine>s that are visible +L<variables|/variable> and L<subroutines|/subroutine> that are visible everywhere in your program. In Perl, only certain special variables are truly global--most variables (and all subroutines) exist only in -the current C<package>. Global variables can be declared with +the current L</package>. Global variables can be declared with L<our|perlfunc/our>. See L<perlfunc/our>. =item global destruction -The C<garbage collection> of globals (and the running of any +The L</garbage collection> of globals (and the running of any associated object destructors) that takes place when a Perl -C<interpreter> is being shut down. Global destruction should not be +L</interpreter> is being shut down. Global destruction should not be confused with the Apocalypse, except perhaps when it should. =item glue language @@ -1252,7 +1255,7 @@ The size of the pieces you're dealing with, mentally speaking. =item greedy -A C<subpattern> whose C<quantifier> wants to match as many things as +A L</subpattern> whose L</quantifier> wants to match as many things as possible. =item grep @@ -1261,8 +1264,8 @@ Originally from the old Unix editor command for "Globally search for a Regular Expression and Print it", now used in the general sense of any kind of search, especially text searches. Perl has a built-in L<grep|perlfunc/grep> function that searches a list for elements -matching any given criterion, whereas the C<grep>(1) program searches -for lines matching a C<regular expression> in one or more files. +matching any given criterion, whereas the I<grep>(1) program searches +for lines matching a L</regular expression> in one or more files. =item group @@ -1272,8 +1275,8 @@ members of your group. =item GV -An internal "glob value" typedef, holding a C<typeglob>. The C<GV> -type is a subclass of C<SV>. +An internal "glob value" typedef, holding a L</typeglob>. The L</GV> +type is a subclass of L</SV>. =back @@ -1286,31 +1289,31 @@ type is a subclass of C<SV>. Someone who is brilliantly persistent in solving technical problems, whether these involve golfing, fighting orcs, or programming. Hacker is a neutral term, morally speaking. Good hackers are not to be -confused with evil C<cracker>s or clueless L<script +confused with evil L<crackers|/cracker> or clueless L<script kiddies|/script kiddie>. If you confuse them, we will presume that you are either evil or clueless. =item handler -A C<subroutine> or C<method> that is called by Perl when your -program needs to respond to some internal event, such as a C<signal>, -or an encounter with an operator subject to C<operator overloading>. -See also C<callback>. +A L</subroutine> or L</method> that is called by Perl when your +program needs to respond to some internal event, such as a L</signal>, +or an encounter with an operator subject to L</operator overloading>. +See also L</callback>. =item hard reference -A C<scalar> C<value> containing the actual address of a -C<referent>, such that the referent's C<reference> count accounts +A L</scalar> L</value> containing the actual address of a +L</referent>, such that the referent's L</reference> count accounts for it. (Some hard references are held internally, such as the -implicit reference from one of a C<typeglob>'s variable slots to its +implicit reference from one of a L</typeglob>'s variable slots to its corresponding referent.) A hard reference is different from a -C<symbolic reference>. +L</symbolic reference>. =item hash -An unordered association of C<key>/C<value> pairs, stored such that -you can easily use a string C<key> to look up its associated data -C<value>. This glossary is like a hash, where the word to be defined +An unordered association of L</key>/L</value> pairs, stored such that +you can easily use a string L</key> to look up its associated data +L</value>. This glossary is like a hash, where the word to be defined is the key, and the definition is the value. A hash is also sometimes septisyllabically called an "associative array", which is a pretty good reason for simply calling it a "hash" instead. @@ -1318,7 +1321,7 @@ good reason for simply calling it a "hash" instead. =item hash table A data structure used internally by Perl for implementing associative -arrays (hashes) efficiently. See also C<bucket>. +arrays (hashes) efficiently. See also L</bucket>. =item header file @@ -1327,13 +1330,13 @@ A file containing certain required definitions that you must include A C header file has a I<.h> extension. Perl doesn't really have header files, though historically Perl has sometimes used translated I<.h> files with a I<.ph> extension. See L<perlfunc/require>. -(Header files have been superseded by the C<module> mechanism.) +(Header files have been superseded by the L</module> mechanism.) =item here document -So called because of a similar construct in C<shell>s that -pretends that the C<line>s following the C<command> are a -separate C<file> to be fed to the command, up to some terminating +So called because of a similar construct in L<shells|/shell> that +pretends that the L<lines|/line> following the L</command> are a +separate L</file> to be fed to the command, up to some terminating string. In Perl, however, it's just a fancy form of quoting. =item hexadecimal @@ -1341,7 +1344,7 @@ string. In Perl, however, it's just a fancy form of quoting. A number in base 16, "hex" for short. The digits for 10 through 16 are customarily represented by the letters C<a> through C<f>. Hexadecimal constants in Perl start with C<0x>. See also -C<perlfunc/hex>. +L<perlfunc/hex>. =item home directory @@ -1359,12 +1362,12 @@ The computer on which a program or other data resides. Excessive pride, the sort of thing Zeus zaps you for. Also the quality that makes you write (and maintain) programs that other people won't want to say bad things about. Hence, the third great virtue of -a programmer. See also C<laziness> and C<impatience>. +a programmer. See also L</laziness> and L</impatience>. =item HV Short for a "hash value" typedef, which holds Perl's internal -representation of a hash. The C<HV> type is a subclass of C<SV>. +representation of a hash. The L</HV> type is a subclass of L</SV>. =back @@ -1378,20 +1381,20 @@ A legally formed name for most anything in which a computer program might be interested. Many languages (including Perl) allow identifiers that start with a letter and contain letters and digits. Perl also counts the underscore character as a valid letter. (Perl -also has more complicated names, such as C<qualified> names.) +also has more complicated names, such as L</qualified> names.) =item impatience The anger you feel when the computer is being lazy. This makes you write programs that don't just react to your needs, but actually anticipate them. Or at least that pretend to. Hence, the second -great virtue of a programmer. See also C<laziness> and C<hubris>. +great virtue of a programmer. See also L</laziness> and L</hubris>. =item implementation How a piece of code actually goes about doing its job. Users of the code should not count on implementation details staying the same -unless they are part of the published C<interface>. +unless they are part of the published L</interface>. =item import @@ -1405,27 +1408,27 @@ so specified). =item indexing -In olden days, the act of looking up a C<key> in an actual index +In olden days, the act of looking up a L</key> in an actual index (such as a phone book), but now merely the act of using any kind of -key or position to find the corresponding C<value>, even if no index +key or position to find the corresponding L</value>, even if no index is involved. Things have degenerated to the point that Perl's L<index|perlfunc/index> function merely locates the position (index) of one string in another. =item indirect filehandle -An C<expression> that evaluates to something that can be used as a -C<filehandle>: a C<string> (filehandle name), a C<typeglob>, a -typeglob C<reference>, or a low-level C<IO> object. +An L</expression> that evaluates to something that can be used as a +L</filehandle>: a L</string> (filehandle name), a L</typeglob>, a +typeglob L</reference>, or a low-level L</IO> object. =item indirect object In English grammar, a short noun phrase between a verb and its direct object indicating the beneficiary or recipient of the action. In Perl, C<print STDOUT "$foo\n";> can be understood as "verb -indirect-object object" where C<STDOUT> is the recipient of the +indirect-object object" where L</STDOUT> is the recipient of the L<print|perlfunc/print> action, and C<"$foo"> is the object being -printed. Similarly, when invoking a C<method>, you might place the +printed. Similarly, when invoking a L</method>, you might place the invocant between the method and its arguments: $gollum = new Pathetic::Creature "Smeagol"; @@ -1437,7 +1440,7 @@ invocant between the method and its arguments: The syntactic position falling between a method call and its arguments when using the indirect object invocation syntax. (The slot is distinguished by the absence of a comma between it and the next -argument.) C<STDERR> is in the indirect object slot here: +argument.) L</STDERR> is in the indirect object slot here: print STDERR "Awake! Awake! Fear, Fire, Foes! Awake!\n"; @@ -1446,29 +1449,29 @@ argument.) C<STDERR> is in the indirect object slot here: If something in a program isn't the value you're looking for but indicates where the value is, that's indirection. This can be done -with either C<symbolic reference>s or L<hard +with either L<symbolic references|/symbolic reference> or L<hard references|/hard reference>. =item infix -An C<operator> that comes in between its C<operand>s, such +An L</operator> that comes in between its L<operands|/operand>, such as multiplication in C<24 * 7>. =item inheritance What you get from your ancestors, genetically or otherwise. If you -happen to be a C<class>, your ancestors are called L<base +happen to be a L</class>, your ancestors are called L<base classes|/base class> and your descendants are called L<derived -classes|/derived class>. See C<single inheritance> and C<multiple +classes|/derived class>. See L</single inheritance> and L</multiple inheritance>. =item instance -Short for "an instance of a class", meaning an C<object> of that C<class>. +Short for "an instance of a class", meaning an L</object> of that L</class>. =item instance variable -An C<attribute> of an C<object>; data stored with the particular +An L</attribute> of an L</object>; data stored with the particular object rather than with the class as a whole. =item integer @@ -1479,7 +1482,7 @@ A number with no fractional (decimal) part. A counting number, like =item interface The services a piece of code promises to provide forever, in contrast to -its C<implementation>, which it should feel free to change whenever it +its L</implementation>, which it should feel free to change whenever it likes. =item interpolation @@ -1489,22 +1492,22 @@ another value, such that it appears to have been there all along. In Perl, variable interpolation happens in double-quoted strings and patterns, and list interpolation occurs when constructing the list of values to pass to a list operator or other such construct that takes a -C<LIST>. +L</LIST>. =item interpreter Strictly speaking, a program that reads a second program and does what the second program says directly without turning the program into a -different form first, which is what C<compiler>s do. Perl +different form first, which is what L<compilers|/compiler> do. Perl is not an interpreter by this definition, because it contains a kind of compiler that takes a program and turns it into a more executable -form (C<syntax tree>s) within the I<perl> process itself, -which the Perl C<run time> system then interprets. +form (L<syntax trees|/syntax tree>) within the I<perl> process itself, +which the Perl L</run time> system then interprets. =item invocant -The agent on whose behalf a C<method> is invoked. In a C<class> -method, the invocant is a package name. In an C<instance> method, +The agent on whose behalf a L</method> is invoked. In a L</class> +method, the invocant is a package name. In an L</instance> method, the invocant is an object reference. =item invocation @@ -1515,11 +1518,11 @@ function to get it do what you think it's supposed to do. We usually =item I/O -Input from, or output to, a C<file> or C<device>. +Input from, or output to, a L</file> or L</device>. =item IO -An internal I/O object. Can also mean C<indirect object>. +An internal I/O object. Can also mean L</indirect object>. =item IP @@ -1531,14 +1534,14 @@ Interprocess Communication. =item is-a -A relationship between two C<object>s in which one object is +A relationship between two L<objects|/object> in which one object is considered to be a more specific version of the other, generic object: "A camel is a mammal." Since the generic object really only exists in a Platonic sense, we usually add a little abstraction to the notion of objects and think of the relationship as being between a generic -C<base class> and a specific C<derived class>. Oddly enough, +L</base class> and a specific L</derived class>. Oddly enough, Platonic classes don't always have Platonic relationships--see -C<inheritance>. +L</inheritance>. =item iteration @@ -1554,8 +1557,8 @@ L<each|perlfunc/each> through it. =item IV The integer four, not to be confused with six, Tom's favorite editor. -IV also means an internal Integer Value of the type a C<scalar> can -hold, not to be confused with an C<NV>. +IV also means an internal Integer Value of the type a L</scalar> can +hold, not to be confused with an L</NV>. =back @@ -1578,12 +1581,12 @@ Contest seen in Usenix signatures. =item key -The string index to a C<hash>, used to look up the C<value> +The string index to a L</hash>, used to look up the L</value> associated with that key. =item keyword -See C<reserved words>. +See L</reserved words>. =back @@ -1593,7 +1596,7 @@ See C<reserved words>. =item label -A name you give to a C<statement> so that you can talk about that +A name you give to a L</statement> so that you can talk about that statement elsewhere in the program. =item laziness @@ -1602,46 +1605,46 @@ The quality that makes you go to great effort to reduce overall energy expenditure. It makes you write labor-saving programs that other people will find useful, and document what you wrote so you don't have to answer so many questions about it. Hence, the first great virtue -of a programmer. Also hence, this book. See also C<impatience> and -C<hubris>. +of a programmer. Also hence, this book. See also L</impatience> and +L</hubris>. =item left shift -A C<bit shift> that multiplies the number by some power of 2. +A L</bit shift> that multiplies the number by some power of 2. =item leftmost longest -The preference of the C<regular expression> engine to match the -leftmost occurrence of a C<pattern>, then given a position at which a +The preference of the L</regular expression> engine to match the +leftmost occurrence of a L</pattern>, then given a position at which a match will occur, the preference for the longest match (presuming the -use of a C<greedy> quantifier). See L<perlre> for I<much> more on +use of a L</greedy> quantifier). See L<perlre> for I<much> more on this subject. =item lexeme -Fancy term for a C<token>. +Fancy term for a L</token>. =item lexer -Fancy term for a C<tokener>. +Fancy term for a L</tokener>. =item lexical analysis -Fancy term for C<tokenizing>. +Fancy term for L</tokenizing>. =item lexical scoping Looking at your I<Oxford English Dictionary> through a microscope. -(Also known as C<static scoping>, because dictionaries don't change +(Also known as L</static scoping>, because dictionaries don't change very fast.) Similarly, looking at variables stored in a private dictionary (namespace) for each scope, which are visible only from their point of declaration down to the end of the lexical scope in -which they are declared. --Syn. C<static scoping>. ---Ant. C<dynamic scoping>. +which they are declared. --Syn. L</static scoping>. +--Ant. L</dynamic scoping>. =item lexical variable -A C<variable> subject to C<lexical scoping>, declared by +A L</variable> subject to L</lexical scoping>, declared by L<my|perlfunc/my>. Often just called a "lexical". (The L<our|perlfunc/our> declaration declares a lexically scoped name for a global variable, which is not itself a lexical variable.) @@ -1650,25 +1653,25 @@ global variable, which is not itself a lexical variable.) Generally, a collection of procedures. In ancient days, referred to a collection of subroutines in a I<.pl> file. In modern times, refers -more often to the entire collection of Perl C<module>s on your +more often to the entire collection of Perl L<modules|/module> on your system. =item LIFO -Last In, First Out. See also C<FIFO>. A LIFO is usually called a -C<stack>. +Last In, First Out. See also L</FIFO>. A LIFO is usually called a +L</stack>. =item line In Unix, a sequence of zero or more non-newline characters terminated -with a C<newline> character. On non-Unix machines, this is emulated -by the C library even if the underlying C<operating system> has +with a L</newline> character. On non-Unix machines, this is emulated +by the C library even if the underlying L</operating system> has different ideas. =item line buffering -Used by a C<standard IE<sol>O> output stream that flushes its -C<buffer> after every C<newline>. Many standard I/O libraries +Used by a L</standard IE<sol>O> output stream that flushes its +L</buffer> after every L</newline>. Many standard I/O libraries automatically set up line buffering on output that is going to the terminal. @@ -1678,13 +1681,13 @@ The number of lines read previous to this one, plus 1. Perl keeps a separate line number for each source or input file it opens. The current source file's line number is represented by C<__LINE__>. The current input line number (for the file that was most recently read -via C<E<lt>FHE<gt>>) is represented by the C<$.> +via C<< E<lt>FHE<gt> >>) is represented by the C<$.> (C<$INPUT_LINE_NUMBER>) variable. Many error messages report both values, if available. =item link -Used as a noun, a name in a C<directory>, representing a C<file>. A +Used as a noun, a name in a L</directory>, representing a L</file>. A given file can have multiple links to it. It's like having the same phone number listed in the phone directory under different names. As a verb, to resolve a partially compiled file's unresolved symbols into @@ -1694,8 +1697,8 @@ dynamic, which has nothing to do with static or dynamic scoping. =item LIST A syntactic construct representing a comma-separated list of -expressions, evaluated to produce a C<list value>. Each -C<expression> in a C<LIST> is evaluated in C<list context> and +expressions, evaluated to produce a L</list value>. Each +L</expression> in a L</LIST> is evaluated in L</list context> and interpolated into the list value. =item list @@ -1704,38 +1707,38 @@ An ordered set of scalar values. =item list context -The situation in which an C<expression> is expected by its +The situation in which an L</expression> is expected by its surroundings (the code calling it) to return a list of values rather -than a single value. Functions that want a C<LIST> of arguments tell +than a single value. Functions that want a L</LIST> of arguments tell those arguments that they should produce a list value. See also -C<context>. +L</context>. =item list operator -An C<operator> that does something with a list of values, such as +An L</operator> that does something with a list of values, such as L<join|perlfunc/join> or L<grep|perlfunc/grep>. Usually used for named built-in operators (such as L<print|perlfunc/print>, L<unlink|perlfunc/unlink>, and L<system|perlfunc/system>) that do not -require parentheses around their C<argument> list. +require parentheses around their L</argument> list. =item list value An unnamed list of temporary scalar values that may be passed around within a program from any list-generating function to any function or -construct that provides a C<list context>. +construct that provides a L</list context>. =item literal -A token in a programming language such as a number or C<string> that -gives you an actual C<value> instead of merely representing possible -values as a C<variable> does. +A token in a programming language such as a number or L</string> that +gives you an actual L</value> instead of merely representing possible +values as a L</variable> does. =item little-endian From Swift: someone who eats eggs little end first. Also used of -computers that store the least significant C<byte> of a word at a +computers that store the least significant L</byte> of a word at a lower byte address than the most significant byte. Often considered -superior to big-endian machines. See also C<big-endian>. +superior to big-endian machines. See also L</big-endian>. =item local @@ -1749,12 +1752,12 @@ Symbols representing the concepts "and", "or", "xor", and "not". =item lookahead -An C<assertion> that peeks at the string to the right of the current +An L</assertion> that peeks at the string to the right of the current match location. =item lookbehind -An C<assertion> that peeks at the string to the left of the current +An L</assertion> that peeks at the string to the left of the current match location. =item loop @@ -1764,7 +1767,7 @@ A construct that performs something repeatedly, like a roller coaster. =item loop control statement Any statement within the body of a loop that can make a loop -prematurely stop looping or skip an C<iteration>. Generally you +prematurely stop looping or skip an L</iteration>. Generally you shouldn't try this on roller coasters. =item loop label @@ -1775,20 +1778,20 @@ control. =item lvaluable -Able to serve as an C<lvalue>. +Able to serve as an L</lvalue>. =item lvalue Term used by language lawyers for a storage location you can assign a -new C<value> to, such as a C<variable> or an element of an -C<array>. The "l" is short for "left", as in the left side of an -assignment, a typical place for lvalues. An C<lvaluable> function or +new L</value> to, such as a L</variable> or an element of an +L</array>. The "l" is short for "left", as in the left side of an +assignment, a typical place for lvalues. An L</lvaluable> function or expression is one to which a value may be assigned, as in C<pos($x) = 10>. =item lvalue modifier -An adjectival pseudofunction that warps the meaning of an C<lvalue> +An adjectival pseudofunction that warps the meaning of an L</lvalue> in some declarative fashion. Currently there are three lvalue modifiers: L<my|perlfunc/my>, L<our|perlfunc/our>, and L<local|perlfunc/local>. @@ -1807,7 +1810,7 @@ Magical things happen when you diddle those variables. =item magical increment -An C<increment> operator that knows how to bump up alphabetics as +An L</increment> operator that knows how to bump up alphabetics as well as numbers. =item magical variables @@ -1821,7 +1824,7 @@ current system error number or message. =item Makefile A file that controls the compilation of a program. Perl programs -don't usually need a C<Makefile> because the Perl compiler has plenty +don't usually need a L</Makefile> because the Perl compiler has plenty of self-control. =item man @@ -1831,28 +1834,28 @@ you. =item manpage -A "page" from the manuals, typically accessed via the C<man>(1) +A "page" from the manuals, typically accessed via the I<man>(1) command. A manpage contains a SYNOPSIS, a DESCRIPTION, a list of BUGS, and so on, and is typically longer than a page. There are -manpages documenting C<command>s, C<syscall>s, -C<library> C<function>s, C<device>s, -C<protocol>s, C<file>s, and such. In this book, we +manpages documenting L<commands|/command>, L<syscalls|/syscall>, +L</library> L<functions|/function>, L<devices|/device>, +L<protocols|/protocol>, L<files|/file>, and such. In this book, we call any piece of standard Perl documentation (like I<perlop> or I<perldelta>) a manpage, no matter what format it's installed in on your system. =item matching -See C<pattern matching>. +See L</pattern matching>. =item member data -See C<instance variable>. +See L</instance variable>. =item memory This always means your main memory, not your disk. Clouding the issue -is the fact that your machine may implement C<virtual> memory; that +is the fact that your machine may implement L</virtual> memory; that is, it will pretend that it has more memory than it really does, and it'll use disk space to hold inactive bits. This can make it seem like you have a little more memory than you really do, but it's not a @@ -1864,23 +1867,23 @@ thrashed your disk to death first. =item metacharacter -A C<character> that is I<not> supposed to be treated normally. Which +A L</character> that is I<not> supposed to be treated normally. Which characters are to be treated specially as metacharacters varies -greatly from context to context. Your C<shell> will have certain -metacharacters, double-quoted Perl C<string>s have other -metacharacters, and C<regular expression> patterns have all the +greatly from context to context. Your L</shell> will have certain +metacharacters, double-quoted Perl L<strings|/string> have other +metacharacters, and L</regular expression> patterns have all the double-quote metacharacters plus some extra ones of their own. =item metasymbol -Something we'd call a C<metacharacter> except that it's a sequence of +Something we'd call a L</metacharacter> except that it's a sequence of more than one character. Generally, the first character in the sequence must be a true metacharacter to get the other characters in the metasymbol to misbehave along with it. =item method -A kind of action that an C<object> can take if you tell it to. See +A kind of action that an L</object> can take if you tell it to. See L<perlobj>. =item minimalism @@ -1891,18 +1894,18 @@ a big language, it turns out small. Go figure. =item mode -In the context of the I<stat>(2) syscall, refers to the field holding -the C<permission bits> and the type of the C<file>. +In the context of the L<stat> syscall, refers to the field holding +the L</permission bits> and the type of the L</file>. =item modifier -See C<statement modifier>, C<regular expression modifier>, and -C<lvalue modifier>, not necessarily in that order. +See L</statement modifier>, L</regular expression modifier>, and +L</lvalue modifier>, not necessarily in that order. =item module -A C<file> that defines a C<package> of (almost) the same name, which -can either C<export> symbols or function as an C<object> class. (A +A L</file> that defines a L</package> of (almost) the same name, which +can either L</export> symbols or function as an L</object> class. (A module's main I<.pm> file may also load in other files in support of the module.) See the L<use|perlfunc/use> built-in. @@ -1923,13 +1926,13 @@ finishes. =item multidimensional array An array with multiple subscripts for finding a single element. Perl -implements these using C<reference>s--see L<perllol> and +implements these using L<references|/reference>--see L<perllol> and L<perldsc>. =item multiple inheritance The features you got from your mother and father, mixed together -unpredictably. (See also C<inheritance>, and C<single +unpredictably. (See also L</inheritance>, and L</single inheritance>.) In computer languages (including Perl), the notion that a given class may have multiple direct ancestors or L<base classes|/base class>. @@ -1942,18 +1945,18 @@ classes|/base class>. =item named pipe -A C<pipe> with a name embedded in the C<filesystem> so that it can -be accessed by two unrelated C<process>es. +A L</pipe> with a name embedded in the L</filesystem> so that it can +be accessed by two unrelated L<processes|/process>. =item namespace A domain of names. You needn't worry about whether the names in one -such domain have been used in another. See C<package>. +such domain have been used in another. See L</package>. =item network address The most important attribute of a socket, like your telephone's -telephone number. Typically an IP address. See also C<port>. +telephone number. Typically an IP address. See also L</port>. =item newline @@ -1976,30 +1979,30 @@ strings, but Perl allows strings to contain a null. =item null list -A C<list value> with zero elements, represented in Perl by C<()>. +A L</list value> with zero elements, represented in Perl by C<()>. =item null string -A C<string> containing no characters, not to be confused with a -string containing a C<null character>, which has a positive length -and is C<true>. +A L</string> containing no characters, not to be confused with a +string containing a L</null character>, which has a positive length +and is L</true>. =item numeric context The situation in which an expression is expected by its surroundings -(the code calling it) to return a number. See also C<context> and -C<string context>. +(the code calling it) to return a number. See also L</context> and +L</string context>. =item NV Short for Nevada, no part of which will ever be confused with civilization. NV also means an internal floating-point Numeric Value -of the type a C<scalar> can hold, not to be confused with an C<IV>. +of the type a L</scalar> can hold, not to be confused with an L</IV>. =item nybble -Half a C<byte>, equivalent to one C<hexadecimal> digit, and worth -four C<bit>s. +Half a L</byte>, equivalent to one L</hexadecimal> digit, and worth +four L<bits|/bit>. =back @@ -2009,7 +2012,7 @@ four C<bit>s. =item object -An C<instance> of a C<class>. Something that "knows" what +An L</instance> of a L</class>. Something that "knows" what user-defined type (class) it is, and what it can do because of what class it is. Your program can request an object to do things, but the object gets to decide whether it wants to do them or not. Some @@ -2040,13 +2043,13 @@ detailed definition, see L<http://www.opensource.org/osd.html>. =item operand -An C<expression> that yields a C<value> that an C<operator> -operates on. See also C<precedence>. +An L</expression> that yields a L</value> that an L</operator> +operates on. See also L</precedence>. =item operating system A special program that runs on the bare machine and hides the gory -details of managing C<process>es and C<device>s. +details of managing L<processes|/process> and L<devices|/device>. Usually used in a looser sense to indicate a particular culture of programming. The loose sense can be used at varying levels of specificity. At one extreme, you might say that all versions of Unix @@ -2056,52 +2059,52 @@ extreme, you could say this particular version of this particular vendor's operating system is different from any other version of this or any other vendor's operating system. Perl is much more portable across operating systems than many other languages. See also -C<architecture> and C<platform>. +L</architecture> and L</platform>. =item operator A gizmo that transforms some number of input values to some number of output values, often built into a language with a special syntax or symbol. A given operator may have specific expectations about what -C<type>s of data you give as its arguments -(C<operand>s) and what type of data you want back from it. +L<types|/type> of data you give as its arguments +(L<operands|/operand>) and what type of data you want back from it. =item operator overloading -A kind of C<overloading> that you can do on built-in -C<operator>s to make them work on C<object>s as if +A kind of L</overloading> that you can do on built-in +L<operators|/operator> to make them work on L<objects|/object> as if the objects were ordinary scalar values, but with the actual semantics supplied by the object class. This is set up with the L<overload> -C<pragma>. +L</pragma>. =item options -See either C<switch> or C<regular expression modifier>. +See either L<switches|/switch> or L</regular expression modifier>. =item overloading Giving additional meanings to a symbol or construct. Actually, all languages do overloading to one extent or another, since people are -good at figuring out things from C<context>. +good at figuring out things from L</context>. =item overriding Hiding or invalidating some other definition of the same name. (Not -to be confused with C<overloading>, which adds definitions that must +to be confused with L</overloading>, which adds definitions that must be disambiguated some other way.) To confuse the issue further, we use the word with two overloaded definitions: to describe how you can -define your own C<subroutine> to hide a built-in C<function> of the +define your own L</subroutine> to hide a built-in L</function> of the same name (see L<perlsub/Overriding Built-in Functions>) and to -describe how you can define a replacement C<method> in a C<derived -class> to hide a C<base class>'s method of the same name (see +describe how you can define a replacement L</method> in a L</derived +class> to hide a L</base class>'s method of the same name (see L<perlobj>). =item owner The one user (apart from the superuser) who has absolute control over -a C<file>. A file may also have a C<group> of users who may +a L</file>. A file may also have a L</group> of users who may exercise joint ownership if the real owner permits it. See -C<permission bits>. +L</permission bits>. =back @@ -2111,9 +2114,9 @@ C<permission bits>. =item package -A C<namespace> for global C<variable>s, -C<subroutine>s, and the like, such that they can be kept -separate from like-named C<symbol>s in other namespaces. In a +A L</namespace> for global L<variables|/variable>, +L<subroutines|/subroutine>, and the like, such that they can be kept +separate from like-named L<symbols|/symbol> in other namespaces. In a sense, only the package is global, since the symbols in the package's symbol table are only accessible from code compiled outside the package by naming the package. But in another sense, all package @@ -2121,58 +2124,58 @@ symbols are also globals--they're just well-organized globals. =item pad -Short for C<scratchpad>. +Short for L</scratchpad>. =item parameter -See C<argument>. +See L</argument>. =item parent class -See C<base class>. +See L</base class>. =item parse tree -See C<syntax tree>. +See L</syntax tree>. =item parsing The subtle but sometimes brutal art of attempting to turn your -possibly malformed program into a valid C<syntax tree>. +possibly malformed program into a valid L</syntax tree>. =item patch To fix by applying one, as it were. In the realm of hackerdom, a listing of the differences between two versions of a program as might -be applied by the C<patch>(1) program when you want to fix a bug or +be applied by the I<patch>(1) program when you want to fix a bug or upgrade your old version. =item PATH The list of L<directories|/directory> the system searches to find a -program you want to C<execute>. The list is stored as one of your -C<environment variable>s, accessible in Perl as +program you want to L</execute>. The list is stored as one of your +L<environment variables|/environment variable>, accessible in Perl as C<$ENV{PATH}>. =item pathname A fully qualified filename such as I</usr/bin/perl>. Sometimes -confused with C<PATH>. +confused with L</PATH>. =item pattern -A template used in C<pattern matching>. +A template used in L</pattern matching>. =item pattern matching -Taking a pattern, usually a C<regular expression>, and trying the +Taking a pattern, usually a L</regular expression>, and trying the pattern various ways on a string to see whether there's any way to make it fit. Often used to pick interesting tidbits out of a file. =item permission bits -Bits that the C<owner> of a file sets or unsets to allow or disallow -access to other people. These flag bits are part of the C<mode> word +Bits that the L</owner> of a file sets or unsets to allow or disallow +access to other people. These flag bits are part of the L</mode> word returned by the L<stat|perlfunc/stat> built-in when you ask about a file. On Unix systems, you can check the I<ls>(1) manpage for more information. @@ -2185,15 +2188,15 @@ hair. Lather, rinse, iterate. =item pipe -A direct C<connection> that carries the output of one C<process> to +A direct L</connection> that carries the output of one L</process> to the input of another without an intermediate temporary file. Once the pipe is set up, the two processes in question can read and write as if they were talking to a normal file, with some caveats. =item pipeline -A series of C<process>es all in a row, linked by -C<pipe>s, where each passes its output stream to the next. +A series of L<processes|/process> all in a row, linked by +L<pipes|/pipe>, where each passes its output stream to the next. =item platform @@ -2212,16 +2215,16 @@ L<perlpod>. =item pointer -A C<variable> in a language like C that contains the exact memory +A L</variable> in a language like C that contains the exact memory location of some other item. Perl handles pointers internally so you don't have to worry about them. Instead, you just use symbolic -pointers in the form of C<key>s and C<variable> names, or L<hard +pointers in the form of L<keys|/key> and L</variable> names, or L<hard references|/hard reference>, which aren't pointers (but act like pointers and do in fact contain pointers). =item polymorphism -The notion that you can tell an C<object> to do something generic, +The notion that you can tell an L</object> to do something generic, and the object will interpret the command in different ways depending on its type. [E<lt>Gk many shapes] @@ -2237,13 +2240,13 @@ than originally intended, or the verb denoting this conversion. Once upon a time, C code compilable under both BSD and SysV. In general, code that can be easily converted to run on another -C<platform>, where "easily" can be defined however you like, and +L</platform>, where "easily" can be defined however you like, and usually is. Anything may be considered portable if you try hard enough. See I<mobile home> or I<London Bridge>. =item porter -Someone who "carries" software from one C<platform> to another. +Someone who "carries" software from one L</platform> to another. Porting programs written in platform-dependent languages such as C can be difficult work, but porting programs like Perl is very much worth the agony. @@ -2254,7 +2257,7 @@ The Portable Operating System Interface specification. =item postfix -An C<operator> that follows its C<operand>, as in C<$x++>. +An L</operator> that follows its L</operand>, as in C<$x++>. =item pp @@ -2275,17 +2278,17 @@ you always do multiplication before addition. =item prefix -An C<operator> that precedes its C<operand>, as in C<++$x>. +An L</operator> that precedes its L</operand>, as in C<++$x>. =item preprocessing -What some helper C<process> did to transform the incoming data into a +What some helper L</process> did to transform the incoming data into a form more suitable for the current process. Often done with an -incoming C<pipe>. See also C<C preprocessor>. +incoming L</pipe>. See also L</C preprocessor>. =item procedure -A C<subroutine>. +A L</subroutine>. =item process @@ -2299,15 +2302,15 @@ Under other operating systems, processes are sometimes called =item program generator A system that algorithmically writes code for you in a high-level -language. See also C<code generator>. +language. See also L</code generator>. =item progressive matching -Merely C<pattern matching> that picks up where it left off before. +L<Pattern matching|/pattern matching> that picks up where it left off before. =item property -See either C<instance variable> or C<character property>. +See either L</instance variable> or L</character property>. =item protocol @@ -2316,17 +2319,17 @@ so that neither correspondent will get too confused. =item prototype -An optional part of a C<subroutine> declaration telling the Perl +An optional part of a L</subroutine> declaration telling the Perl compiler how many and what flavor of arguments may be passed as -C<actual arguments>, so that you can write subroutine calls that +L</actual arguments>, so that you can write subroutine calls that parse much like built-in functions. (Or don't parse, as the case may be.) =item pseudofunction A construct that sometimes looks like a function but really isn't. -Usually reserved for C<lvalue> modifiers like L<my|perlfunc/my>, for -C<context> modifiers like L<scalar|perlfunc/scalar>, and for the +Usually reserved for L</lvalue> modifiers like L<my|perlfunc/my>, for +L</context> modifiers like L<scalar|perlfunc/scalar>, and for the pick-your-own-quotes constructs, C<q//>, C<qq//>, C<qx//>, C<qw//>, C<qr//>, C<m//>, C<s///>, C<y///>, and C<tr///>. @@ -2338,14 +2341,14 @@ an array reference or a hash reference. =item pseudoliteral -An C<operator> that looks something like a C<literal>, such as the -output-grabbing operator, C<`>C<command>C<`>. +An L</operator> that looks something like a L</literal>, such as the +output-grabbing operator, C<`>I<C<command>>C<`>. =item public domain Something not owned by anybody. Perl is copyrighted and is thus -I<not> in the public domain--it's just C<freely available> and -C<freely redistributable>. +I<not> in the public domain--it's just L</freely available> and +L</freely redistributable>. =item pumpkin @@ -2354,7 +2357,7 @@ the lead integrator in some arena of development. =item pumpking -A C<pumpkin> holder, the person in charge of pumping the pump, or at +A L</pumpkin> holder, the person in charge of pumping the pump, or at least priming it. Must be willing to play the part of the Great Pumpkin now and then. @@ -2376,8 +2379,8 @@ the top-level directory. =item quantifier -A component of a C<regular expression> specifying how many times the -foregoing C<atom> may occur. +A component of a L</regular expression> specifying how many times the +foregoing L</atom> may occur. =back @@ -2394,16 +2397,16 @@ what it's trying to do. =item reaping -The last rites performed by a parent C<process> on behalf of a -deceased child process so that it doesn't remain a C<zombie>. See +The last rites performed by a parent L</process> on behalf of a +deceased child process so that it doesn't remain a L</zombie>. See the L<wait|perlfunc/wait> and L<waitpid|perlfunc/waitpid> function calls. =item record -A set of related data values in a C<file> or C<stream>, often -associated with a unique C<key> field. In Unix, often commensurate -with a C<line>, or a blank-line-terminated set of lines (a +A set of related data values in a L</file> or L</stream>, often +associated with a unique L</key> field. In Unix, often commensurate +with a L</line>, or a blank-line-terminated set of lines (a "paragraph"). Each line of the I</etc/passwd> file is a record, keyed on login name, containing information about that user. @@ -2417,7 +2420,7 @@ like an infinite loop with more spectacular failure modes. =item reference Where you look to find a pointer to information somewhere else. (See -C<indirection>.) References come in two flavors, L<symbolic +L</indirection>.) References come in two flavors, L<symbolic references|/symbolic reference> and L<hard references|/hard reference>. @@ -2429,7 +2432,7 @@ subroutines. =item regex -See C<regular expression>. +See L</regular expression>. =item regular expression @@ -2446,34 +2449,34 @@ L<perlre>. =item regular expression modifier An option on a pattern or substitution, such as C</i> to render the -pattern case insensitive. See also C<cloister>. +pattern case insensitive. See also L</cloister>. =item regular file -A C<file> that's not a C<directory>, a C<device>, a named C<pipe> -or C<socket>, or a C<symbolic link>. Perl uses the C<-f> file test +A L</file> that's not a L</directory>, a L</device>, a named L</pipe> +or L</socket>, or a L</symbolic link>. Perl uses the C<-f> file test operator to identify regular files. Sometimes called a "plain" file. =item relational operator -An C<operator> that says whether a particular ordering relationship -is C<true> about a pair of C<operand>s. Perl has both -numeric and string relational operators. See C<collating sequence>. +An L</operator> that says whether a particular ordering relationship +is L</true> about a pair of L<operands|/operand>. Perl has both +numeric and string relational operators. See L</collating sequence>. =item reserved words -A word with a specific, built-in meaning to a C<compiler>, such as +A word with a specific, built-in meaning to a L</compiler>, such as C<if> or L<delete|perlfunc/delete>. In many languages (not Perl), it's illegal to use reserved words to name anything else. (Which is why they're reserved, after all.) In Perl, you just can't use them to -name C<label>s or C<filehandle>s. Also called +name L<labels|/label> or L<filehandles|/filehandle>. Also called "keywords". =item return value -The C<value> produced by a C<subroutine> or C<expression> when -evaluated. In Perl, a return value may be either a C<list> or a -C<scalar>. +The L</value> produced by a L</subroutine> or L</expression> when +evaluated. In Perl, a return value may be either a L</list> or a +L</scalar>. =item RFC @@ -2482,7 +2485,7 @@ of a series of important standards documents. =item right shift -A C<bit shift> that divides a number by some power of 2. +A L</bit shift> that divides a number by some power of 2. =item root @@ -2496,8 +2499,8 @@ What you are told when someone thinks you should Read The Fine Manual. =item run phase Any time after Perl starts running your main program. See also -C<compile phase>. Run phase is mostly spent in C<run time> but may -also be spent in C<compile time> when L<require|perlfunc/require>, +L</compile phase>. Run phase is mostly spent in L</run time> but may +also be spent in L</compile time> when L<require|perlfunc/require>, L<do|perlfunc/do> C<FILE>, or L<eval|perlfunc/eval> C<STRING> operators are executed or when a substitution uses the C</ee> modifier. @@ -2506,13 +2509,13 @@ modifier. The time when Perl is actually doing what your code says to do, as opposed to the earlier period of time when it was trying to figure out -whether what you said made any sense whatsoever, which is C<compile +whether what you said made any sense whatsoever, which is L</compile time>. =item run-time pattern A pattern that contains one or more variables to be interpolated -before parsing the pattern as a C<regular expression>, and that +before parsing the pattern as a L</regular expression>, and that therefore cannot be analyzed at compile time, but must be re-analyzed each time the pattern match operator is evaluated. Run-time patterns are useful but expensive. @@ -2520,13 +2523,13 @@ are useful but expensive. =item RV A recreational vehicle, not to be confused with vehicular recreation. -RV also means an internal Reference Value of the type a C<scalar> can -hold. See also C<IV> and C<NV> if you're not confused yet. +RV also means an internal Reference Value of the type a L</scalar> can +hold. See also L</IV> and L</NV> if you're not confused yet. =item rvalue -A C<value> that you might find on the right side of an -C<assignment>. See also C<lvalue>. +A L</value> that you might find on the right side of an +L</assignment>. See also L</lvalue>. =back @@ -2536,40 +2539,40 @@ C<assignment>. See also C<lvalue>. =item scalar -A simple, singular value; a number, C<string>, or C<reference>. +A simple, singular value; a number, L</string>, or L</reference>. =item scalar context -The situation in which an C<expression> is expected by its -surroundings (the code calling it) to return a single C<value> rather -than a C<list> of values. See also C<context> and C<list context>. +The situation in which an L</expression> is expected by its +surroundings (the code calling it) to return a single L</value> rather +than a L</list> of values. See also L</context> and L</list context>. A scalar context sometimes imposes additional constraints on the -return value--see C<string context> and C<numeric context>. -Sometimes we talk about a C<Boolean context> inside conditionals, but +return value--see L</string context> and L</numeric context>. +Sometimes we talk about a L</Boolean context> inside conditionals, but this imposes no additional constraints, since any scalar value, -whether numeric or C<string>, is already true or false. +whether numeric or L</string>, is already true or false. =item scalar literal -A number or quoted C<string>--an actual C<value> in the text of your -program, as opposed to a C<variable>. +A number or quoted L</string>--an actual L</value> in the text of your +program, as opposed to a L</variable>. =item scalar value -A value that happens to be a C<scalar> as opposed to a C<list>. +A value that happens to be a L</scalar> as opposed to a L</list>. =item scalar variable -A C<variable> prefixed with C<$> that holds a single value. +A L</variable> prefixed with C<$> that holds a single value. =item scope How far away you can see a variable from, looking through one. Perl -has two visibility mechanisms: it does C<dynamic scoping> of -L<local|perlfunc/local> C<variable>s, meaning that the rest -of the C<block>, and any C<subroutine>s that are called +has two visibility mechanisms: it does L</dynamic scoping> of +L<local|perlfunc/local> L<variables|/variable>, meaning that the rest +of the L</block>, and any L<subroutines|/subroutine> that are called by the rest of the block, can see the variables that are local to the -block. Perl does C<lexical scoping> of L<my|perlfunc/my> variables, +block. Perl does L</lexical scoping> of L<my|perlfunc/my> variables, meaning that the rest of the block can see the variable, but other subroutines called by the block I<cannot> see the variable. @@ -2581,15 +2584,15 @@ scoped variables. =item script -A text C<file> that is a program intended to be C<execute>d +A text L</file> that is a program intended to be L<executed|/execute> directly rather than L<compiled|/compiler> to another form of file -before execution. Also, in the context of C<Unicode>, a writing +before execution. Also, in the context of L</Unicode>, a writing system for a particular language or group of languages, such as Greek, Bengali, or Klingon. =item script kiddie -A C<cracker> who is not a C<hacker>, but knows just enough to run +A L</cracker> who is not a L</hacker>, but knows just enough to run canned scripts. A cargo-cult programmer. =item sed @@ -2598,27 +2601,27 @@ A venerable Stream EDitor from which Perl derives some of its ideas. =item semaphore -A fancy kind of interlock that prevents multiple C<thread>s or -C<process>es from using up the same resources simultaneously. +A fancy kind of interlock that prevents multiple L<threads|/thread> or +L<processes|/process> from using up the same resources simultaneously. =item separator -A C<character> or C<string> that keeps two surrounding strings from +A L</character> or L</string> that keeps two surrounding strings from being confused with each other. The L<split|perlfunc/split> function -works on separators. Not to be confused with C<delimiter>s -or C<terminator>s. The "or" in the previous sentence +works on separators. Not to be confused with L<delimiters|/delimiter> +or L<terminators|/terminator>. The "or" in the previous sentence separated the two alternatives. =item serialization -Putting a fancy C<data structure> into linear order so that it can be -stored as a C<string> in a disk file or database or sent through a -C<pipe>. Also called marshalling. +Putting a fancy L</data structure> into linear order so that it can be +stored as a L</string> in a disk file or database or sent through a +L</pipe>. Also called marshalling. =item server -In networking, a C<process> that either advertises a C<service> or -just hangs around at a known location and waits for C<client>s +In networking, a L</process> that either advertises a L</service> or +just hangs around at a known location and waits for L<clients|/client> who need service to get in touch with it. =item service @@ -2629,22 +2632,22 @@ services are listed by the L<getservent|perlfunc/getservent> function. =item setgid -Same as C<setuid>, only having to do with giving away C<group> +Same as L</setuid>, only having to do with giving away L</group> privileges. =item setuid -Said of a program that runs with the privileges of its C<owner> +Said of a program that runs with the privileges of its L</owner> rather than (as is usually the case) the privileges of whoever is -running it. Also describes the bit in the mode word (C<permission +running it. Also describes the bit in the mode word (L</permission bits>) that controls the feature. This bit must be explicitly set by the owner to enable this feature, and the program must be carefully written not to give away more privileges than it ought to. =item shared memory -A piece of C<memory> accessible by two different -C<process>es who otherwise would not see each other's memory. +A piece of L</memory> accessible by two different +L<processes|/process> who otherwise would not see each other's memory. =item shebang @@ -2654,10 +2657,10 @@ where to find the interpreter. =item shell -A C<command>-line C<interpreter>. The program that interactively -gives you a prompt, accepts one or more C<line>s of input, and +A L</command>-line L</interpreter>. The program that interactively +gives you a prompt, accepts one or more L<lines|/line> of input, and executes the programs you mentioned, feeding each of them their proper -C<argument>s and input data. Shells can also execute +L<arguments|/argument> and input data. Shells can also execute scripts containing such commands. Under Unix, typical shells include the Bourne shell (I</bin/sh>), the C shell (I</bin/csh>), and the Korn shell (I</bin/ksh>). Perl is not strictly a shell because it's not @@ -2665,124 +2668,123 @@ interactive (although Perl programs can be interactive). =item side effects -Something extra that happens when you evaluate an C<expression>. +Something extra that happens when you evaluate an L</expression>. Nowadays it can refer to almost anything. For example, evaluating a simple assignment statement typically has the "side effect" of assigning a value to a variable. (And you thought assigning the value was your primary intent in the first place!) Likewise, assigning a -value to the special variable L<$E<verbar> -($AUTOFLUSH)|perlvar/$AUTOFLUSH>) has the side effect of forcing a -flush after every L<write|perlfunc/write> or L<print|perlfunc/print> -on the currently selected filehandle. +value to the special variable C<$|> (C<$AUTOFLUSH>) has the side +effect of forcing a flush after every L<write|perlfunc/write> or +L<print|perlfunc/print> on the currently selected filehandle. =item signal A bolt out of the blue; that is, an event triggered by the -C<operating system>, probably when you're least expecting it. +L</operating system>, probably when you're least expecting it. =item signal handler -A C<subroutine> that, instead of being content to be called in the +A L</subroutine> that, instead of being content to be called in the normal fashion, sits around waiting for a bolt out of the blue before -it will deign to C<execute>. Under Perl, bolts out of the blue are +it will deign to L</execute>. Under Perl, bolts out of the blue are called signals, and you send them with the L<kill|perlfunc/kill> built-in. See L<perlvar/%SIG> and L<perlipc/Signals>. =item single inheritance The features you got from your mother, if she told you that you don't -have a father. (See also C<inheritance> and C<multiple +have a father. (See also L</inheritance> and L</multiple inheritance>.) In computer languages, the notion that -C<class>es reproduce asexually so that a given class can only -have one direct ancestor or C<base class>. Perl supplies no such +L<classes|/class> reproduce asexually so that a given class can only +have one direct ancestor or L</base class>. Perl supplies no such restriction, though you may certainly program Perl that way if you like. =item slice -A selection of any number of C<element>s from a C<list>, -C<array>, or C<hash>. +A selection of any number of L<elements|/element> from a L</list>, +L</array>, or L</hash>. =item slurp -To read an entire C<file> into a C<string> in one operation. +To read an entire L</file> into a L</string> in one operation. =item socket An endpoint for network communication among multiple -C<process>es that works much like a telephone or a post -office box. The most important thing about a socket is its C<network +L<processes|/process> that works much like a telephone or a post +office box. The most important thing about a socket is its L</network address> (like a phone number). Different kinds of sockets have different kinds of addresses--some look like filenames, and some don't. =item soft reference -See C<symbolic reference>. +See L</symbolic reference>. =item source filter -A special kind of C<module> that does C<preprocessing> on your -script just before it gets to the C<tokener>. +A special kind of L</module> that does L</preprocessing> on your +script just before it gets to the L</tokener>. =item stack A device you can put things on the top of, and later take them back -off in the opposite order in which you put them on. See C<LIFO>. +off in the opposite order in which you put them on. See L</LIFO>. =item standard Included in the official Perl distribution, as in a standard module, a -standard tool, or a standard Perl C<manpage>. +standard tool, or a standard Perl L</manpage>. =item standard error -The default output C<stream> for nasty remarks that don't belong in -C<standard output>. Represented within a Perl program by the -C<filehandle> C<STDERR>. You can use this stream explicitly, but the +The default output L</stream> for nasty remarks that don't belong in +L</standard output>. Represented within a Perl program by the +L</filehandle> L</STDERR>. You can use this stream explicitly, but the L<die|perlfunc/die> and L<warn|perlfunc/warn> built-ins write to your standard error stream automatically. =item standard I/O -A standard C library for doing C<buffer>ed input and output to -the C<operating system>. (The "standard" of standard I/O is only +A standard C library for doing L<buffered|/buffer> input and output to +the L</operating system>. (The "standard" of standard I/O is only marginally related to the "standard" of standard input and output.) In general, Perl relies on whatever implementation of standard I/O a given operating system supplies, so the buffering characteristics of a Perl program on one machine may not exactly match those on another machine. Normally this only influences efficiency, not semantics. If your standard I/O package is doing block buffering and you want it to -C<flush> the buffer more often, just set the C<$|> variable to a true +L</flush> the buffer more often, just set the C<$|> variable to a true value. =item standard input -The default input C<stream> for your program, which if possible +The default input L</stream> for your program, which if possible shouldn't care where its data is coming from. Represented within a -Perl program by the C<filehandle> C<STDIN>. +Perl program by the L</filehandle> L</STDIN>. =item standard output -The default output C<stream> for your program, which if possible +The default output L</stream> for your program, which if possible shouldn't care where its data is going. Represented within a Perl -program by the C<filehandle> C<STDOUT>. +program by the L</filehandle> L</STDOUT>. =item stat structure A special internal spot in which Perl keeps the information about the -last C<file> on which you requested information. +last L</file> on which you requested information. =item statement -A C<command> to the computer about what to do next, like a step in a +A L</command> to the computer about what to do next, like a step in a recipe: "Add marmalade to batter and mix until mixed." A statement is -distinguished from a C<declaration>, which doesn't tell the computer +distinguished from a L</declaration>, which doesn't tell the computer to do anything, but just to learn something. =item statement modifier -A C<conditional> or C<loop> that you put after the C<statement> +A L</conditional> or L</loop> that you put after the L</statement> instead of before, if you know what we mean. =item static @@ -2792,52 +2794,52 @@ is relatively stable compared to something else, except for certain elementary particles, and we're not so sure about them.) In computers, where things are supposed to vary rapidly, "static" has a derogatory connotation, indicating a slightly dysfunctional -C<variable>, C<subroutine>, or C<method>. In Perl culture, the +L</variable>, L</subroutine>, or L</method>. In Perl culture, the word is politely avoided. =item static method -No such thing. See C<class method>. +No such thing. See L</class method>. =item static scoping -No such thing. See C<lexical scoping>. +No such thing. See L</lexical scoping>. =item static variable -No such thing. Just use a C<lexical variable> in a scope larger than -your C<subroutine>. +No such thing. Just use a L</lexical variable> in a scope larger than +your L</subroutine>. =item status -The C<value> returned to the parent C<process> when one of its child +The L</value> returned to the parent L</process> when one of its child processes dies. This value is placed in the special variable C<$?>. -Its upper eight C<bit>s are the exit status of the defunct +Its upper eight L<bits|/bit> are the exit status of the defunct process, and its lower eight bits identify the signal (if any) that the process died from. On Unix systems, this status value is the same as the status word returned by I<wait>(2). See L<perlfunc/system>. =item STDERR -See C<standard error>. +See L</standard error>. =item STDIN -See C<standard input>. +See L</standard input>. =item STDIO -See C<standard IE<sol>O>. +See L</standard IE<sol>O>. =item STDOUT -See C<standard output>. +See L</standard output>. =item stream A flow of data into or out of a process as a steady sequence of bytes or characters, without the appearance of being broken up into packets. -This is a kind of C<interface>--the underlying C<implementation> may +This is a kind of L</interface>--the underlying L</implementation> may well break your data up into separate packets for delivery, but this is hidden from you. @@ -2849,12 +2851,12 @@ not have to be entirely printable. =item string context The situation in which an expression is expected by its surroundings -(the code calling it) to return a C<string>. See also C<context> -and C<numeric context>. +(the code calling it) to return a L</string>. See also L</context> +and L</numeric context>. =item stringification -The process of producing a C<string> representation of an abstract +The process of producing a L</string> representation of an abstract object. =item struct @@ -2863,15 +2865,15 @@ C keyword introducing a structure definition or name. =item structure -See C<data structure>. +See L</data structure>. =item subclass -See C<derived class>. +See L</derived class>. =item subpattern -A component of a C<regular expression> pattern. +A component of a L</regular expression> pattern. =item subroutine @@ -2879,60 +2881,60 @@ A named or otherwise accessible piece of program that can be invoked from elsewhere in the program in order to accomplish some sub-goal of the program. A subroutine is often parameterized to accomplish different but related things depending on its input -C<argument>s. If the subroutine returns a meaningful -C<value>, it is also called a C<function>. +L<arguments|/argument>. If the subroutine returns a meaningful +L</value>, it is also called a L</function>. =item subscript -A C<value> that indicates the position of a particular C<array> -C<element> in an array. +A L</value> that indicates the position of a particular L</array> +L</element> in an array. =item substitution Changing parts of a string via the C<s///> operator. (We avoid use of -this term to mean C<variable interpolation>.) +this term to mean L</variable interpolation>.) =item substring -A portion of a C<string>, starting at a certain C<character> -position (C<offset>) and proceeding for a certain number of +A portion of a L</string>, starting at a certain L</character> +position (L</offset>) and proceeding for a certain number of characters. =item superclass -See C<base class>. +See L</base class>. =item superuser -The person whom the C<operating system> will let do almost anything. +The person whom the L</operating system> will let do almost anything. Typically your system administrator or someone pretending to be your -system administrator. On Unix systems, the C<root> user. On Windows +system administrator. On Unix systems, the L</root> user. On Windows systems, usually the Administrator user. =item SV Short for "scalar value". But within the Perl interpreter every -C<referent> is treated as a member of a class derived from SV, in an -object-oriented sort of way. Every C<value> inside Perl is passed -around as a C language C<SV*> pointer. The SV C<struct> knows its +L</referent> is treated as a member of a class derived from SV, in an +object-oriented sort of way. Every L</value> inside Perl is passed +around as a C language C<SV*> pointer. The SV L</struct> knows its own "referent type", and the code is smart enough (we hope) not to try -to call a C<hash> function on a C<subroutine>. +to call a L</hash> function on a L</subroutine>. =item switch An option you give on a command line to influence the way your program works, usually introduced with a minus sign. The word is also used as -a nickname for a C<switch statement>. +a nickname for a L</switch statement>. =item switch cluster The combination of multiple command-line switches (e.g., B<-a -b -c>) into one switch (e.g., B<-abc>). Any switch with an additional -C<argument> must be the last switch in a cluster. +L</argument> must be the last switch in a cluster. =item switch statement -A program technique that lets you evaluate an C<expression> and then, +A program technique that lets you evaluate an L</expression> and then, based on the value of the expression, do a multiway branch to the appropriate piece of code for that value. Also called a "case structure", named after the similar Pascal construct. Most switch @@ -2941,19 +2943,19 @@ Switch Statements>. =item symbol -Generally, any C<token> or C<metasymbol>. Often used more -specifically to mean the sort of name you might find in a C<symbol +Generally, any L</token> or L</metasymbol>. Often used more +specifically to mean the sort of name you might find in a L</symbol table>. =item symbol table -Where a C<compiler> remembers symbols. A program like Perl must -somehow remember all the names of all the C<variable>s, -C<filehandle>s, and C<subroutine>s you've +Where a L</compiler> remembers symbols. A program like Perl must +somehow remember all the names of all the L<variables|/variable>, +L<filehandles|/filehandle>, and L<subroutines|/subroutine> you've used. It does this by placing the names in a symbol table, which is -implemented in Perl using a C<hash table>. There is a separate -symbol table for each C<package> to give each package its own -C<namespace>. +implemented in Perl using a L</hash table>. There is a separate +symbol table for each L</package> to give each package its own +L</namespace>. =item symbolic debugger @@ -2965,17 +2967,17 @@ which your program is written. =item symbolic link -An alternate filename that points to the real C<filename>, which in -turn points to the real C<file>. Whenever the C<operating system> -is trying to parse a C<pathname> containing a symbolic link, it +An alternate filename that points to the real L</filename>, which in +turn points to the real L</file>. Whenever the L</operating system> +is trying to parse a L</pathname> containing a symbolic link, it merely substitutes the new name and continues parsing. =item symbolic reference A variable whose value is the name of another variable or subroutine. By L<dereferencing|/dereference> the first variable, you can get at -the second one. Symbolic references are illegal under C<use strict -'refs'>. +the second one. Symbolic references are illegal under L<use strict +'refs'|strict/strict refs>. =item synchronous @@ -2994,12 +2996,12 @@ put together with each other. =item syntax tree An internal representation of your program wherein lower-level -C<construct>s dangle off the higher-level constructs +L<constructs|/construct> dangle off the higher-level constructs enclosing them. =item syscall -A C<function> call directly to the C<operating system>. Many of the +A L</function> call directly to the L</operating system>. Many of the important subroutines and functions you use aren't direct system calls, but are built up in one or more layers above the system call level. In general, Perl programmers don't need to worry about the @@ -3023,42 +3025,42 @@ you would call with Perl's L<system|perlfunc/system> function. Said of data derived from the grubby hands of a user and thus unsafe for a secure program to rely on. Perl does taint checks if you run a -C<setuid> (or C<setgid>) program, or if you use the B<-T> switch. +L</setuid> (or L</setgid>) program, or if you use the B<-T> switch. =item TCP Short for Transmission Control Protocol. A protocol wrapped around the Internet Protocol to make an unreliable packet transmission mechanism appear to the application program to be a reliable -C<stream> of bytes. (Usually.) +L</stream> of bytes. (Usually.) =item term -Short for a "terminal", that is, a leaf node of a C<syntax tree>. A -thing that functions grammatically as an C<operand> for the operators +Short for a "terminal", that is, a leaf node of a L</syntax tree>. A +thing that functions grammatically as an L</operand> for the operators in an expression. =item terminator -A C<character> or C<string> that marks the end of another string. +A L</character> or L</string> that marks the end of another string. The C<$/> variable contains the string that terminates a L<readline|perlfunc/readline> operation, which L<chomp|perlfunc/chomp> deletes from the end. Not to be confused with -C<delimiter>s or C<separator>s. The period at +L<delimiters|/delimiter> or L<separators|/separator>. The period at the end of this sentence is a terminator. =item ternary -An C<operator> taking three C<operand>s. Sometimes -pronounced C<trinary>. +An L</operator> taking three L<operands|/operand>. Sometimes +pronounced L</trinary>. =item text -A C<string> or C<file> containing primarily printable characters. +A L</string> or L</file> containing primarily printable characters. =item thread -Like a forked process, but without C<fork>'s inherent memory +Like a forked process, but without L</fork>'s inherent memory protection. A thread is lighter weight than a full process, in that a process could have multiple threads running around in it, all fighting over the same process's memory space unless steps are taken to protect @@ -3085,11 +3087,11 @@ semantic significance. =item tokener A module that breaks a program text into a sequence of -C<token>s for later analysis by a parser. +L<tokens|/token> for later analysis by a parser. =item tokenizing -Splitting up a program text into C<token>s. Also known as +Splitting up a program text into L<tokens|/token>. Also known as "lexing", in which case you get "lexemes" instead of tokens. =item toolbox approach @@ -3109,12 +3111,12 @@ L<perlop/trE<sol>SEARCHLISTE<sol>REPLACEMENTLISTE<sol>cds>. =item trigger -An event that causes a C<handler> to be run. +An event that causes a L</handler> to be run. =item trinary -Not a stellar system with three stars, but an C<operator> taking -three C<operand>s. Sometimes pronounced C<ternary>. +Not a stellar system with three stars, but an L</operator> taking +three L<operands|/operand>. Sometimes pronounced L</ternary>. =item troff @@ -3134,7 +3136,7 @@ L<truncate|perlfunc/truncate> function. =item type -See C<data type> and C<class>. +See L</data type> and L</class>. =item type casting @@ -3143,7 +3145,7 @@ not need it. Nor want it. =item typed lexical -A C<lexical variable> that is declared with a C<class> type: C<my +A L</lexical variable> that is declared with a L</class> type: C<my Pony $bill>. =item typedef @@ -3160,7 +3162,7 @@ all or only one of them. See L<perldata/Typeglobs and Filehandles>. =item typemap A description of how C types may be transformed to and from Perl types -within an C<extension> module written in C<XS>. +within an L</extension> module written in L</XS>. =back @@ -3170,24 +3172,24 @@ within an C<extension> module written in C<XS>. =item UDP -User Datagram Protocol, the typical way to send C<datagram>s +User Datagram Protocol, the typical way to send L<datagrams|/datagram> over the Internet. =item UID -A user ID. Often used in the context of C<file> or C<process> +A user ID. Often used in the context of L</file> or L</process> ownership. =item umask -A mask of those C<permission bits> that should be forced off when +A mask of those L</permission bits> that should be forced off when creating files or directories, in order to establish a policy of whom you'll ordinarily deny access to. See the L<umask|perlfunc/umask> function. =item unary operator -An operator with only one C<operand>, like C<!> or +An operator with only one L</operand>, like C<!> or L<chdir|perlfunc/chdir>. Unary operators are usually prefix operators; that is, they precede their operand. The C<++> and C<--> operators can be either prefix or postfix. (Their position I<does> @@ -3230,40 +3232,40 @@ value. =item variable A named storage location that can hold any of various kinds of -C<value>, as your program sees fit. +L</value>, as your program sees fit. =item variable interpolation -The C<interpolation> of a scalar or array variable into a string. +The L</interpolation> of a scalar or array variable into a string. =item variadic -Said of a C<function> that happily receives an indeterminate number -of C<actual arguments>. +Said of a L</function> that happily receives an indeterminate number +of L</actual arguments>. =item vector -Mathematical jargon for a list of C<scalar value>s. +Mathematical jargon for a list of L<scalar values|/scalar value>. =item virtual Providing the appearance of something without the reality, as in: -virtual memory is not real memory. (See also C<memory>.) The +virtual memory is not real memory. (See also L</memory>.) The opposite of "virtual" is "transparent", which means providing the reality of something without the appearance, as in: Perl handles the variable-length UTF-8 character encoding transparently. =item void context -A form of C<scalar context> in which an C<expression> is not -expected to return any C<value> at all and is evaluated for its -C<side effects> alone. +A form of L</scalar context> in which an L</expression> is not +expected to return any L</value> at all and is evaluated for its +L</side effects> alone. =item v-string -A "version" or "vector" C<string> specified with a C<v> followed by a +A "version" or "vector" L</string> specified with a C<v> followed by a series of decimal integers in dot notation, for instance, -C<v1.20.300.4000>. Each number turns into a C<character> with the +C<v1.20.300.4000>. Each number turns into a L</character> with the specified ordinal value. (The C<v> is optional when there are at least three integers.) @@ -3275,7 +3277,7 @@ least three integers.) =item warning -A message printed to the C<STDERR> stream to the effect that something +A message printed to the L</STDERR> stream to the effect that something might be wrong but isn't worth blowing up over. See L<perlfunc/warn> and the L<warnings> pragma. @@ -3286,7 +3288,7 @@ the Perl debugger. =item whitespace -A C<character> that moves your cursor but doesn't otherwise put +A L</character> that moves your cursor but doesn't otherwise put anything on your screen. Typically refers to any of: space, tab, line feed, carriage return, or form feed. @@ -3295,17 +3297,17 @@ feed, carriage return, or form feed. In normal "computerese", the piece of data of the size most efficiently handled by your computer, typically 32 bits or so, give or take a few powers of 2. In Perl culture, it more often refers to an -alphanumeric C<identifier> (including underscores), or to a string of -nonwhitespace C<character>s bounded by whitespace or string +alphanumeric L</identifier> (including underscores), or to a string of +nonwhitespace L<characters|/character> bounded by whitespace or string boundaries. =item working directory -Your current C<directory>, from which relative pathnames are -interpreted by the C<operating system>. The operating system knows +Your current L</directory>, from which relative pathnames are +interpreted by the L</operating system>. The operating system knows your current directory because you told it with a L<chdir|perlfunc/chdir> or because you started out in the place where -your parent C<process> was when you were born. +your parent L</process> was when you were born. =item wrapper @@ -3337,7 +3339,7 @@ one. =item XSUB -An external C<subroutine> defined in C<XS>. +An external L</subroutine> defined in L</XS>. =back @@ -3359,8 +3361,8 @@ source distribution. =item zero width -A subpattern C<assertion> matching the C<null string> between -C<character>s. +A subpattern L</assertion> matching the L</null string> between +L<characters|/character>. =item zombie |