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authorPerl 5 Porters <perl5-porters@africa.nicoh.com>1997-03-26 07:04:34 +1200
committerChip Salzenberg <chip@atlantic.net>1997-03-26 07:04:34 +1200
commit54310121b442974721115f93666234a200f5c7e4 (patch)
tree99b5953030ddf062d77206ac0cf8ac967e7cbd93 /pod/perllol.pod
parentd03407ef6d8e534a414e9ce92c6c5c8dab664a40 (diff)
downloadperl-54310121b442974721115f93666234a200f5c7e4.tar.gz
[inseperable changes from patch from perl-5.003_95 to perl-5.003_86]
[editor's note: this commit was prepared manually so may differ in minor ways to other inseperable changes commits] CORE LANGUAGE CHANGES Title: "Support $ENV{PERL5OPT}" From: Chip Salzenberg Files: perl.c pod/perldiag.pod pod/perldelta.pod pod/perlrun.pod Title: "Implement void context, in which C<wantarray> is undef" From: Chip Salzenberg Files: cop.h doop.c dump.c global.sym gv.c op.c op.h perl.c pod/perlcall.pod pod/perldelta.pod pod/perlfunc.pod pod/perlguts.pod pod/perlsub.pod pp.c pp_ctl.c pp_hot.c pp_sys.c proto.h Title: "Don't look up &AUTOLOAD in @ISA when calling plain function" From: Chip Salzenberg Files: global.sym gv.c lib/Text/ParseWords.pm pod/perldelta.pod pp_hot.c proto.h t/op/method.t Title: "Allow closures to be constant subroutines" From: Chip Salzenberg Files: op.c Title: "Make C<scalar(reverse)> mean C<scalar(reverse $_)>" From: Chip Salzenberg Files: pp.c Title: "Fix lexical suicide from C<my $x = $x> in sub" From: Chip Salzenberg Files: op.c Title: "Make "Unrecog. char." fatal, and update its doc" From: Chip Salzenberg Files: pod/perldiag.pod toke.c CORE PORTABILITY Title: "safefree() mismatch" From: Roderick Schertler Msg-ID: <21338.859653381@eeyore.ibcinc.com> Date: Sat, 29 Mar 1997 11:36:21 -0500 Files: util.c (applied based on p5p patch as commit id 9b9b466fb02dc96c81439bafbb3b2da55238cfd2) Title: "Win32 update (seven patches)" From: Gurusamy Sarathy and Nick Ing-Simmons Files: EXTERN.h MANIFEST win32/Makefile win32/perl.mak win32/perl.rc win32/perldll.mak win32/makedef.pl win32/modules.mak win32/win32io.c win32/bin/pl2bat.bat OTHER CORE CHANGES Title: "Report PERL* environment variables in -V and perlbug" From: Chip Salzenberg Files: perl.c utils/perlbug.PL Title: "Typo in perl.c: Printing NO_EMBED for perl -V" From: Gisle Aas Msg-ID: <199703301922.VAA13509@furubotn.sn.no> Date: Sun, 30 Mar 1997 21:22:11 +0200 Files: perl.c (applied based on p5p patch as commit id b6c639e4b1912ad03b9b10ba9518d96bd0a6cfaf) Title: "Don't let C<$var = $var> untaint $var" From: Chip Salzenberg Files: pp_hot.c pp_sys.c sv.h t/op/taint.t Title: "Fix autoviv bug in C<my $x; ++$x->{KEY}>" From: Chip Salzenberg Files: pp_hot.c Title: "Re: 5.004's new srand() default seed" From: Hallvard B Furuseth Msg-ID: <199703302219.AAA20998@bombur2.uio.no> Date: Mon, 31 Mar 1997 00:19:13 +0200 (MET DST) Files: pp.c (applied based on p5p patch as commit id d7d933a26349f945f93b2f0dbf85b773d8ca3219) Title: "Re: embedded perl and top_env problem " From: Gurusamy Sarathy Msg-ID: <199703280031.TAA05711@aatma.engin.umich.edu> Date: Thu, 27 Mar 1997 19:31:42 -0500 Files: gv.c interp.sym perl.c perl.h pp_ctl.c pp_sys.c scope.h util.c (applied based on p5p patch as commit id f289f7d2518e7a8a82114282e774adf50fa6ce85) Title: "Define and use new macro: boolSV()" From: Tim Bunce Files: gv.c lib/ExtUtils/typemap os2/os2.c pp.c pp_hot.c pp_sys.c sv.c sv.h universal.c vms/vms.c Title: "Re: strict @F" From: Hallvard B Furuseth Msg-ID: <199703252110.WAA16038@bombur2.uio.no> Date: Tue, 25 Mar 1997 22:10:33 +0100 (MET) Files: toke.c (applied based on p5p patch as commit id dfd44a5c8c8dd4c001c595debfe73d011a96d844) Title: "Try harder to identify errors at EOF" From: Chip Salzenberg Files: toke.c Title: "Minor string change in toke.c: 'bareword'" From: lvirden@cas.org Msg-ID: <1997Mar27.130247.1911552@hmivax.humgen.upenn.edu> Date: Thu, 27 Mar 1997 13:02:46 -0500 (EST) Files: toke.c (applied based on p5p patch as commit id 9b56c8f8085a9e773ad87c6b3c1d0b5e39dbc348) Title: "Improve diagnostic on \r in program text" From: Chip Salzenberg Files: pod/perldiag.pod toke.c Title: "Make Sock_size_t typedef work right" From: Chip Salzenberg Files: perl.h pp_sys.c LIBRARY AND EXTENSIONS Title: "New module constant.pm" From: Tom Phoenix Files: MANIFEST lib/constant.pm op.c pp.c t/pragma/constant.t Title: "Remove chat2" From: Chip Salzenberg Files: MANIFEST lib/chat2.inter lib/chat2.pl Title: "Include CGI.pm 2.32" From: Chip Salzenberg Files: MANIFEST eg/cgi/* lib/CGI.pm lib/CGI/Apache.pm lib/CGI/Carp.pm lib/CGI/Fast.pm lib/CGI/Push.pm lib/CGI/Switch.pm UTILITIES Title: "Tom C's Pod::Html and html tools, as of 30 March 97" From: Chip Salzenberg Files: MANIFEST installhtml lib/Pod/Html.pm pod/pod2html.PL Title: "Fix path bugs in installhtml" From: Robin Barker <rmb1@cise.npl.co.uk> Msg-ID: <3180.9703270906@tempest.cise.npl.co.uk> Date: Thu, 27 Mar 97 09:06:14 GMT Files: installhtml Title: "Make perlbug say that it's only for core Perl bugs" From: Chip Salzenberg Files: utils/perlbug.PL DOCUMENTATION Title: "Document autouse and constant; update diagnostics" From: Chip Salzenberg Files: pod/perldelta.pod Title: "Suggest to upgraders that they try '-w' again" From: Hallvard B Furuseth Msg-ID: <199703251901.UAA15982@bombur2.uio.no> Date: Tue, 25 Mar 1997 20:01:26 +0100 (MET) Files: pod/perldelta.pod (applied based on p5p patch as commit id 4176c059b9ba6b022e99c44270434a5c3e415b73) Title: "Improve and update documentation of constant subs" From: Tom Phoenix <rootbeer@teleport.com> Msg-ID: <Pine.GSO.3.96.970331122546.14185C-100000@kelly.teleport.com> Date: Mon, 31 Mar 1997 13:05:54 -0800 (PST) Files: pod/perlsub.pod Title: "Improve documentation of C<return>" From: Chip Salzenberg Files: pod/perlfunc.pod pod/perlsub.pod Title: "perlfunc.pod patch" From: Gisle Aas Msg-ID: <199703262159.WAA17531@furubotn.sn.no> Date: Wed, 26 Mar 1997 22:59:23 +0100 Files: pod/perlfunc.pod (applied based on p5p patch as commit id 35a731fcbcd7860eb497d6598f3f77b8746319c4) Title: "Use 'while (defined($x = <>)) {}', per <gnat@frii.com>" From: Chip Salzenberg Files: configpm lib/Term/Cap.pm perlsh pod/perlipc.pod pod/perlop.pod pod/perlsub.pod pod/perlsyn.pod pod/perltrap.pod pod/perlvar.pod win32/bin/search.bat Title: "Document and test C<%> behavior with negative operands" From: Chip Salzenberg Files: pod/perlop.pod t/op/arith.t Title: "Update docs on $]" From: Chip Salzenberg Files: pod/perlvar.pod Title: "perlvar.pod patch" From: Gisle Aas Msg-ID: <199703261254.NAA10237@bergen.sn.no> Date: Wed, 26 Mar 1997 13:54:00 +0100 Files: pod/perlvar.pod (applied based on p5p patch as commit id 0aa182cb0caa3829032904b9754807b1b7418509) Title: "Fix example of C<or> vs. C<||>" From: Chip Salzenberg Files: pod/perlsyn.pod Title: "Pod usage and spelling patch" From: Larry W. Virden Files: pod/*.pod Title: "Pod updates" From: "Cary D. Renzema" <caryr@mxim.com> Msg-ID: <199703262353.PAA01819@macs.mxim.com> Date: Wed, 26 Mar 1997 15:53:22 -0800 (PST) Files: pod/*.pod (applied based on p5p patch as commit id 5695b28edc67a3f45e8a0f25755d07afef3660ac)
Diffstat (limited to 'pod/perllol.pod')
-rw-r--r--pod/perllol.pod60
1 files changed, 30 insertions, 30 deletions
diff --git a/pod/perllol.pod b/pod/perllol.pod
index f15b24384e..ac36364ae0 100644
--- a/pod/perllol.pod
+++ b/pod/perllol.pod
@@ -16,7 +16,7 @@ old array @LoL that you can get at with two subscripts, like C<$LoL[3][2]>. Her
a declaration of the array:
# assign to our array a list of list references
- @LoL = (
+ @LoL = (
[ "fred", "barney" ],
[ "george", "jane", "elroy" ],
[ "homer", "marge", "bart" ],
@@ -39,10 +39,10 @@ but rather just a reference to it, you could do something more like this:
print $ref_to_LoL->[2][2];
-Notice that the outer bracket type has changed, and so our access syntax
+Notice that the outer bracket type has changed, and so our access syntax
has also changed. That's because unlike C, in perl you can't freely
-interchange arrays and references thereto. $ref_to_LoL is a reference to an
-array, whereas @LoL is an array proper. Likewise, C<$LoL[2]> is not an
+interchange arrays and references thereto. $ref_to_LoL is a reference to an
+array, whereas @LoL is an array proper. Likewise, C<$LoL[2]> is not an
array, but an array ref. So how come you can write these:
$LoL[2][2]
@@ -72,7 +72,7 @@ each line is a row and each word an element. If you're trying to develop an
while (<>) {
@tmp = split;
push @LoL, [ @tmp ];
- }
+ }
You might also have loaded that from a function:
@@ -81,7 +81,7 @@ You might also have loaded that from a function:
}
Or you might have had a temporary variable sitting around with the
-list in it.
+list in it.
for $i ( 1 .. 10 ) {
@tmp = somefunc($i);
@@ -93,8 +93,8 @@ constructor. That's because this will be very wrong:
$LoL[$i] = @tmp;
-You see, assigning a named list like that to a scalar just counts the
-number of elements in @tmp, which probably isn't what you want.
+You see, assigning a named list like that to a scalar just counts the
+number of elements in @tmp, which probably isn't what you want.
If you are running under C<use strict>, you'll have to add some
declarations to make it happy:
@@ -104,13 +104,13 @@ declarations to make it happy:
while (<>) {
@tmp = split;
push @LoL, [ @tmp ];
- }
+ }
Of course, you don't need the temporary array to have a name at all:
while (<>) {
push @LoL, [ split ];
- }
+ }
You also don't have to use push(). You could just make a direct assignment
if you knew where you wanted to put it:
@@ -119,30 +119,30 @@ if you knew where you wanted to put it:
for $i ( 0 .. 10 ) {
$line = <>;
$LoL[$i] = [ split ' ', $line ];
- }
+ }
or even just
my (@LoL, $i);
for $i ( 0 .. 10 ) {
$LoL[$i] = [ split ' ', <> ];
- }
+ }
You should in general be leery of using potential list functions
-in a scalar context without explicitly stating such.
+in a scalar context without explicitly stating such.
This would be clearer to the casual reader:
my (@LoL, $i);
for $i ( 0 .. 10 ) {
$LoL[$i] = [ split ' ', scalar(<>) ];
- }
+ }
If you wanted to have a $ref_to_LoL variable as a reference to an array,
you'd have to do something like this:
while (<>) {
push @$ref_to_LoL, [ split ];
- }
+ }
Actually, if you were using strict, you'd have to declare not only
$ref_to_LoL as you had to declare @LoL, but you'd I<also> having to
@@ -152,7 +152,7 @@ perl version 5.001m that's been fixed for the 5.002 release.)
my $ref_to_LoL = [];
while (<>) {
push @$ref_to_LoL, [ split ];
- }
+ }
Ok, now you can add new rows. What about adding new columns? If you're
dealing with just matrices, it's often easiest to use simple assignment:
@@ -165,9 +165,9 @@ dealing with just matrices, it's often easiest to use simple assignment:
for $x ( 3, 7, 9 ) {
$LoL[$x][20] += func2($x);
- }
+ }
-It doesn't matter whether those elements are already
+It doesn't matter whether those elements are already
there or not: it'll gladly create them for you, setting
intervening elements to C<undef> as need be.
@@ -186,7 +186,7 @@ to push() must be a real array, not just a reference to such.
=head1 Access and Printing
-Now it's time to print your data structure out. How
+Now it's time to print your data structure out. How
are you going to do that? Well, if you want only one
of the elements, it's trivial:
@@ -198,10 +198,10 @@ say
print @LoL; # WRONG
because you'll get just references listed, and perl will never
-automatically dereference things for you. Instead, you have to
+automatically dereference things for you. Instead, you have to
roll yourself a loop or two. This prints the whole structure,
using the shell-style for() construct to loop across the outer
-set of subscripts.
+set of subscripts.
for $aref ( @LoL ) {
print "\t [ @$aref ],\n";
@@ -221,7 +221,7 @@ or maybe even this. Notice the inner loop.
}
}
-As you can see, it's getting a bit complicated. That's why
+As you can see, it's getting a bit complicated. That's why
sometimes is easier to take a temporary on your way through:
for $i ( 0 .. $#LoL ) {
@@ -254,10 +254,10 @@ Here's how to do one operation using a loop. We'll assume an @LoL
variable as before.
@part = ();
- $x = 4;
+ $x = 4;
for ($y = 7; $y < 13; $y++) {
push @part, $LoL[$x][$y];
- }
+ }
That same loop could be replaced with a slice operation:
@@ -273,9 +273,9 @@ $x run from 4..8 and $y run from 7 to 12? Hmm... here's the simple way:
for ($starty = $y = 7; $x <= 12; $y++) {
$newLoL[$x - $startx][$y - $starty] = $LoL[$x][$y];
}
- }
+ }
-We can reduce some of the looping through slices
+We can reduce some of the looping through slices
for ($x = 4; $x <= 8; $x++) {
push @newLoL, [ @{ $LoL[$x] } [ 7..12 ] ];
@@ -293,13 +293,13 @@ If I were you, I'd put that in a function:
@newLoL = splice_2D( \@LoL, 4 => 8, 7 => 12 );
sub splice_2D {
my $lrr = shift; # ref to list of list refs!
- my ($x_lo, $x_hi,
+ my ($x_lo, $x_hi,
$y_lo, $y_hi) = @_;
- return map {
- [ @{ $lrr->[$_] } [ $y_lo .. $y_hi ] ]
+ return map {
+ [ @{ $lrr->[$_] } [ $y_lo .. $y_hi ] ]
} $x_lo .. $x_hi;
- }
+ }
=head1 SEE ALSO