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Diffstat (limited to 'cpan/Pod-Parser/lib/Pod/Select.pm')
-rw-r--r-- | cpan/Pod-Parser/lib/Pod/Select.pm | 1496 |
1 files changed, 748 insertions, 748 deletions
diff --git a/cpan/Pod-Parser/lib/Pod/Select.pm b/cpan/Pod-Parser/lib/Pod/Select.pm index 300eee537e..148b5d17cf 100644 --- a/cpan/Pod-Parser/lib/Pod/Select.pm +++ b/cpan/Pod-Parser/lib/Pod/Select.pm @@ -1,748 +1,748 @@ -############################################################################# -# Pod/Select.pm -- function to select portions of POD docs -# -# Copyright (C) 1996-2000 by Bradford Appleton. All rights reserved. -# This file is part of "PodParser". PodParser is free software; -# you can redistribute it and/or modify it under the same terms -# as Perl itself. -############################################################################# - -package Pod::Select; -use strict; - -use vars qw($VERSION @ISA @EXPORT $MAX_HEADING_LEVEL %myData @section_headings @selected_sections); -$VERSION = '1.51'; ## Current version of this package -require 5.005; ## requires this Perl version or later - -############################################################################# - -=head1 NAME - -Pod::Select, podselect() - extract selected sections of POD from input - -=head1 SYNOPSIS - - use Pod::Select; - - ## Select all the POD sections for each file in @filelist - ## and print the result on standard output. - podselect(@filelist); - - ## Same as above, but write to tmp.out - podselect({-output => "tmp.out"}, @filelist): - - ## Select from the given filelist, only those POD sections that are - ## within a 1st level section named any of: NAME, SYNOPSIS, OPTIONS. - podselect({-sections => ["NAME|SYNOPSIS", "OPTIONS"]}, @filelist): - - ## Select the "DESCRIPTION" section of the PODs from STDIN and write - ## the result to STDERR. - podselect({-output => ">&STDERR", -sections => ["DESCRIPTION"]}, \*STDIN); - -or - - use Pod::Select; - - ## Create a parser object for selecting POD sections from the input - $parser = new Pod::Select(); - - ## Select all the POD sections for each file in @filelist - ## and print the result to tmp.out. - $parser->parse_from_file("<&STDIN", "tmp.out"); - - ## Select from the given filelist, only those POD sections that are - ## within a 1st level section named any of: NAME, SYNOPSIS, OPTIONS. - $parser->select("NAME|SYNOPSIS", "OPTIONS"); - for (@filelist) { $parser->parse_from_file($_); } - - ## Select the "DESCRIPTION" and "SEE ALSO" sections of the PODs from - ## STDIN and write the result to STDERR. - $parser->select("DESCRIPTION"); - $parser->add_selection("SEE ALSO"); - $parser->parse_from_filehandle(\*STDIN, \*STDERR); - -=head1 REQUIRES - -perl5.005, Pod::Parser, Exporter, Carp - -=head1 EXPORTS - -podselect() - -=head1 DESCRIPTION - -B<podselect()> is a function which will extract specified sections of -pod documentation from an input stream. This ability is provided by the -B<Pod::Select> module which is a subclass of B<Pod::Parser>. -B<Pod::Select> provides a method named B<select()> to specify the set of -POD sections to select for processing/printing. B<podselect()> merely -creates a B<Pod::Select> object and then invokes the B<podselect()> -followed by B<parse_from_file()>. - -=head1 SECTION SPECIFICATIONS - -B<podselect()> and B<Pod::Select::select()> may be given one or more -"section specifications" to restrict the text processed to only the -desired set of sections and their corresponding subsections. A section -specification is a string containing one or more Perl-style regular -expressions separated by forward slashes ("/"). If you need to use a -forward slash literally within a section title you can escape it with a -backslash ("\/"). - -The formal syntax of a section specification is: - -=over 4 - -=item * - -I<head1-title-regex>/I<head2-title-regex>/... - -=back - -Any omitted or empty regular expressions will default to ".*". -Please note that each regular expression given is implicitly -anchored by adding "^" and "$" to the beginning and end. Also, if a -given regular expression starts with a "!" character, then the -expression is I<negated> (so C<!foo> would match anything I<except> -C<foo>). - -Some example section specifications follow. - -=over 4 - -=item * - -Match the C<NAME> and C<SYNOPSIS> sections and all of their subsections: - -C<NAME|SYNOPSIS> - -=item * - -Match only the C<Question> and C<Answer> subsections of the C<DESCRIPTION> -section: - -C<DESCRIPTION/Question|Answer> - -=item * - -Match the C<Comments> subsection of I<all> sections: - -C</Comments> - -=item * - -Match all subsections of C<DESCRIPTION> I<except> for C<Comments>: - -C<DESCRIPTION/!Comments> - -=item * - -Match the C<DESCRIPTION> section but do I<not> match any of its subsections: - -C<DESCRIPTION/!.+> - -=item * - -Match all top level sections but none of their subsections: - -C</!.+> - -=back - -=begin _NOT_IMPLEMENTED_ - -=head1 RANGE SPECIFICATIONS - -B<podselect()> and B<Pod::Select::select()> may be given one or more -"range specifications" to restrict the text processed to only the -desired ranges of paragraphs in the desired set of sections. A range -specification is a string containing a single Perl-style regular -expression (a regex), or else two Perl-style regular expressions -(regexs) separated by a ".." (Perl's "range" operator is ".."). -The regexs in a range specification are delimited by forward slashes -("/"). If you need to use a forward slash literally within a regex you -can escape it with a backslash ("\/"). - -The formal syntax of a range specification is: - -=over 4 - -=item * - -/I<start-range-regex>/[../I<end-range-regex>/] - -=back - -Where each the item inside square brackets (the ".." followed by the -end-range-regex) is optional. Each "range-regex" is of the form: - - =cmd-expr text-expr - -Where I<cmd-expr> is intended to match the name of one or more POD -commands, and I<text-expr> is intended to match the paragraph text for -the command. If a range-regex is supposed to match a POD command, then -the first character of the regex (the one after the initial '/') -absolutely I<must> be a single '=' character; it may not be anything -else (not even a regex meta-character) if it is supposed to match -against the name of a POD command. - -If no I<=cmd-expr> is given then the text-expr will be matched against -plain textblocks unless it is preceded by a space, in which case it is -matched against verbatim text-blocks. If no I<text-expr> is given then -only the command-portion of the paragraph is matched against. - -Note that these two expressions are each implicitly anchored. This -means that when matching against the command-name, there will be an -implicit '^' and '$' around the given I<=cmd-expr>; and when matching -against the paragraph text there will be an implicit '\A' and '\Z' -around the given I<text-expr>. - -Unlike with section-specs, the '!' character does I<not> have any special -meaning (negation or otherwise) at the beginning of a range-spec! - -Some example range specifications follow. - -=over 4 - -=item -Match all C<=for html> paragraphs: - -C</=for html/> - -=item -Match all paragraphs between C<=begin html> and C<=end html> -(note that this will I<not> work correctly if such sections -are nested): - -C</=begin html/../=end html/> - -=item -Match all paragraphs between the given C<=item> name until the end of the -current section: - -C</=item mine/../=head\d/> - -=item -Match all paragraphs between the given C<=item> until the next item, or -until the end of the itemized list (note that this will I<not> work as -desired if the item contains an itemized list nested within it): - -C</=item mine/../=(item|back)/> - -=back - -=end _NOT_IMPLEMENTED_ - -=cut - -############################################################################# - -#use diagnostics; -use Carp; -use Pod::Parser 1.04; - -@ISA = qw(Pod::Parser); -@EXPORT = qw(&podselect); - -## Maximum number of heading levels supported for '=headN' directives -*MAX_HEADING_LEVEL = \3; - -############################################################################# - -=head1 OBJECT METHODS - -The following methods are provided in this module. Each one takes a -reference to the object itself as an implicit first parameter. - -=cut - -##--------------------------------------------------------------------------- - -## =begin _PRIVATE_ -## -## =head1 B<_init_headings()> -## -## Initialize the current set of active section headings. -## -## =cut -## -## =end _PRIVATE_ - -sub _init_headings { - my $self = shift; - local *myData = $self; - - ## Initialize current section heading titles if necessary - unless (defined $myData{_SECTION_HEADINGS}) { - local *section_headings = $myData{_SECTION_HEADINGS} = []; - for (my $i = 0; $i < $MAX_HEADING_LEVEL; ++$i) { - $section_headings[$i] = ''; - } - } -} - -##--------------------------------------------------------------------------- - -=head1 B<curr_headings()> - - ($head1, $head2, $head3, ...) = $parser->curr_headings(); - $head1 = $parser->curr_headings(1); - -This method returns a list of the currently active section headings and -subheadings in the document being parsed. The list of headings returned -corresponds to the most recently parsed paragraph of the input. - -If an argument is given, it must correspond to the desired section -heading number, in which case only the specified section heading is -returned. If there is no current section heading at the specified -level, then C<undef> is returned. - -=cut - -sub curr_headings { - my $self = shift; - $self->_init_headings() unless (defined $self->{_SECTION_HEADINGS}); - my @headings = @{ $self->{_SECTION_HEADINGS} }; - return (@_ > 0 and $_[0] =~ /^\d+$/) ? $headings[$_[0] - 1] : @headings; -} - -##--------------------------------------------------------------------------- - -=head1 B<select()> - - $parser->select($section_spec1,$section_spec2,...); - -This method is used to select the particular sections and subsections of -POD documentation that are to be printed and/or processed. The existing -set of selected sections is I<replaced> with the given set of sections. -See B<add_selection()> for adding to the current set of selected -sections. - -Each of the C<$section_spec> arguments should be a section specification -as described in L<"SECTION SPECIFICATIONS">. The section specifications -are parsed by this method and the resulting regular expressions are -stored in the invoking object. - -If no C<$section_spec> arguments are given, then the existing set of -selected sections is cleared out (which means C<all> sections will be -processed). - -This method should I<not> normally be overridden by subclasses. - -=cut - -sub select { - my ($self, @sections) = @_; - local *myData = $self; - local $_; - -### NEED TO DISCERN A SECTION-SPEC FROM A RANGE-SPEC (look for m{^/.+/$}?) - - ##--------------------------------------------------------------------- - ## The following is a blatant hack for backward compatibility, and for - ## implementing add_selection(). If the *first* *argument* is the - ## string "+", then the remaining section specifications are *added* - ## to the current set of selections; otherwise the given section - ## specifications will *replace* the current set of selections. - ## - ## This should probably be fixed someday, but for the present time, - ## it seems incredibly unlikely that "+" would ever correspond to - ## a legitimate section heading - ##--------------------------------------------------------------------- - my $add = ($sections[0] eq '+') ? shift(@sections) : ''; - - ## Reset the set of sections to use - unless (@sections) { - delete $myData{_SELECTED_SECTIONS} unless ($add); - return; - } - $myData{_SELECTED_SECTIONS} = [] - unless ($add && exists $myData{_SELECTED_SECTIONS}); - local *selected_sections = $myData{_SELECTED_SECTIONS}; - - ## Compile each spec - for my $spec (@sections) { - if ( defined($_ = _compile_section_spec($spec)) ) { - ## Store them in our sections array - push(@selected_sections, $_); - } - else { - carp qq{Ignoring section spec "$spec"!\n}; - } - } -} - -##--------------------------------------------------------------------------- - -=head1 B<add_selection()> - - $parser->add_selection($section_spec1,$section_spec2,...); - -This method is used to add to the currently selected sections and -subsections of POD documentation that are to be printed and/or -processed. See <select()> for replacing the currently selected sections. - -Each of the C<$section_spec> arguments should be a section specification -as described in L<"SECTION SPECIFICATIONS">. The section specifications -are parsed by this method and the resulting regular expressions are -stored in the invoking object. - -This method should I<not> normally be overridden by subclasses. - -=cut - -sub add_selection { - my $self = shift; - return $self->select('+', @_); -} - -##--------------------------------------------------------------------------- - -=head1 B<clear_selections()> - - $parser->clear_selections(); - -This method takes no arguments, it has the exact same effect as invoking -<select()> with no arguments. - -=cut - -sub clear_selections { - my $self = shift; - return $self->select(); -} - -##--------------------------------------------------------------------------- - -=head1 B<match_section()> - - $boolean = $parser->match_section($heading1,$heading2,...); - -Returns a value of true if the given section and subsection heading -titles match any of the currently selected section specifications in -effect from prior calls to B<select()> and B<add_selection()> (or if -there are no explicitly selected/deselected sections). - -The arguments C<$heading1>, C<$heading2>, etc. are the heading titles of -the corresponding sections, subsections, etc. to try and match. If -C<$headingN> is omitted then it defaults to the current corresponding -section heading title in the input. - -This method should I<not> normally be overridden by subclasses. - -=cut - -sub match_section { - my $self = shift; - my (@headings) = @_; - local *myData = $self; - - ## Return true if no restrictions were explicitly specified - my $selections = (exists $myData{_SELECTED_SECTIONS}) - ? $myData{_SELECTED_SECTIONS} : undef; - return 1 unless ((defined $selections) && @{$selections}); - - ## Default any unspecified sections to the current one - my @current_headings = $self->curr_headings(); - for (my $i = 0; $i < $MAX_HEADING_LEVEL; ++$i) { - (defined $headings[$i]) or $headings[$i] = $current_headings[$i]; - } - - ## Look for a match against the specified section expressions - for my $section_spec ( @{$selections} ) { - ##------------------------------------------------------ - ## Each portion of this spec must match in order for - ## the spec to be matched. So we will start with a - ## match-value of 'true' and logically 'and' it with - ## the results of matching a given element of the spec. - ##------------------------------------------------------ - my $match = 1; - for (my $i = 0; $i < $MAX_HEADING_LEVEL; ++$i) { - my $regex = $section_spec->[$i]; - my $negated = ($regex =~ s/^\!//); - $match &= ($negated ? ($headings[$i] !~ /${regex}/) - : ($headings[$i] =~ /${regex}/)); - last unless ($match); - } - return 1 if ($match); - } - return 0; ## no match -} - -##--------------------------------------------------------------------------- - -=head1 B<is_selected()> - - $boolean = $parser->is_selected($paragraph); - -This method is used to determine if the block of text given in -C<$paragraph> falls within the currently selected set of POD sections -and subsections to be printed or processed. This method is also -responsible for keeping track of the current input section and -subsections. It is assumed that C<$paragraph> is the most recently read -(but not yet processed) input paragraph. - -The value returned will be true if the C<$paragraph> and the rest of the -text in the same section as C<$paragraph> should be selected (included) -for processing; otherwise a false value is returned. - -=cut - -sub is_selected { - my ($self, $paragraph) = @_; - local $_; - local *myData = $self; - - $self->_init_headings() unless (defined $myData{_SECTION_HEADINGS}); - - ## Keep track of current sections levels and headings - $_ = $paragraph; - if (/^=((?:sub)*)(?:head(?:ing)?|sec(?:tion)?)(\d*)\s+(.*?)\s*$/) - { - ## This is a section heading command - my ($level, $heading) = ($2, $3); - $level = 1 + (length($1) / 3) if ((! length $level) || (length $1)); - ## Reset the current section heading at this level - $myData{_SECTION_HEADINGS}->[$level - 1] = $heading; - ## Reset subsection headings of this one to empty - for (my $i = $level; $i < $MAX_HEADING_LEVEL; ++$i) { - $myData{_SECTION_HEADINGS}->[$i] = ''; - } - } - - return $self->match_section(); -} - -############################################################################# - -=head1 EXPORTED FUNCTIONS - -The following functions are exported by this module. Please note that -these are functions (not methods) and therefore C<do not> take an -implicit first argument. - -=cut - -##--------------------------------------------------------------------------- - -=head1 B<podselect()> - - podselect(\%options,@filelist); - -B<podselect> will print the raw (untranslated) POD paragraphs of all -POD sections in the given input files specified by C<@filelist> -according to the given options. - -If any argument to B<podselect> is a reference to a hash -(associative array) then the values with the following keys are -processed as follows: - -=over 4 - -=item B<-output> - -A string corresponding to the desired output file (or ">&STDOUT" -or ">&STDERR"). The default is to use standard output. - -=item B<-sections> - -A reference to an array of sections specifications (as described in -L<"SECTION SPECIFICATIONS">) which indicate the desired set of POD -sections and subsections to be selected from input. If no section -specifications are given, then all sections of the PODs are used. - -=begin _NOT_IMPLEMENTED_ - -=item B<-ranges> - -A reference to an array of range specifications (as described in -L<"RANGE SPECIFICATIONS">) which indicate the desired range of POD -paragraphs to be selected from the desired input sections. If no range -specifications are given, then all paragraphs of the desired sections -are used. - -=end _NOT_IMPLEMENTED_ - -=back - -All other arguments should correspond to the names of input files -containing POD sections. A file name of "-" or "<&STDIN" will -be interpreted to mean standard input (which is the default if no -filenames are given). - -=cut - -sub podselect { - my(@argv) = @_; - my %defaults = (); - my $pod_parser = new Pod::Select(%defaults); - my $num_inputs = 0; - my $output = '>&STDOUT'; - my %opts; - local $_; - for (@argv) { - if (ref($_)) { - next unless (ref($_) eq 'HASH'); - %opts = (%defaults, %{$_}); - - ##------------------------------------------------------------- - ## Need this for backward compatibility since we formerly used - ## options that were all uppercase words rather than ones that - ## looked like Unix command-line options. - ## to be uppercase keywords) - ##------------------------------------------------------------- - %opts = map { - my ($key, $val) = (lc $_, $opts{$_}); - $key =~ s/^(?=\w)/-/; - $key =~ /^-se[cl]/ and $key = '-sections'; - #! $key eq '-range' and $key .= 's'; - ($key => $val); - } (keys %opts); - - ## Process the options - (exists $opts{'-output'}) and $output = $opts{'-output'}; - - ## Select the desired sections - $pod_parser->select(@{ $opts{'-sections'} }) - if ( (defined $opts{'-sections'}) - && ((ref $opts{'-sections'}) eq 'ARRAY') ); - - #! ## Select the desired paragraph ranges - #! $pod_parser->select(@{ $opts{'-ranges'} }) - #! if ( (defined $opts{'-ranges'}) - #! && ((ref $opts{'-ranges'}) eq 'ARRAY') ); - } - else { - $pod_parser->parse_from_file($_, $output); - ++$num_inputs; - } - } - $pod_parser->parse_from_file('-') unless ($num_inputs > 0); -} - -############################################################################# - -=head1 PRIVATE METHODS AND DATA - -B<Pod::Select> makes uses a number of internal methods and data fields -which clients should not need to see or use. For the sake of avoiding -name collisions with client data and methods, these methods and fields -are briefly discussed here. Determined hackers may obtain further -information about them by reading the B<Pod::Select> source code. - -Private data fields are stored in the hash-object whose reference is -returned by the B<new()> constructor for this class. The names of all -private methods and data-fields used by B<Pod::Select> begin with a -prefix of "_" and match the regular expression C</^_\w+$/>. - -=cut - -##--------------------------------------------------------------------------- - -=begin _PRIVATE_ - -=head1 B<_compile_section_spec()> - - $listref = $parser->_compile_section_spec($section_spec); - -This function (note it is a function and I<not> a method) takes a -section specification (as described in L<"SECTION SPECIFICATIONS">) -given in C<$section_sepc>, and compiles it into a list of regular -expressions. If C<$section_spec> has no syntax errors, then a reference -to the list (array) of corresponding regular expressions is returned; -otherwise C<undef> is returned and an error message is printed (using -B<carp>) for each invalid regex. - -=end _PRIVATE_ - -=cut - -sub _compile_section_spec { - my ($section_spec) = @_; - my (@regexs, $negated); - - ## Compile the spec into a list of regexs - local $_ = $section_spec; - s{\\\\}{\001}g; ## handle escaped backward slashes - s{\\/}{\002}g; ## handle escaped forward slashes - - ## Parse the regexs for the heading titles - @regexs = split(/\//, $_, $MAX_HEADING_LEVEL); - - ## Set default regex for ommitted levels - for (my $i = 0; $i < $MAX_HEADING_LEVEL; ++$i) { - $regexs[$i] = '.*' unless ((defined $regexs[$i]) - && (length $regexs[$i])); - } - ## Modify the regexs as needed and validate their syntax - my $bad_regexs = 0; - for (@regexs) { - $_ .= '.+' if ($_ eq '!'); - s{\001}{\\\\}g; ## restore escaped backward slashes - s{\002}{\\/}g; ## restore escaped forward slashes - $negated = s/^\!//; ## check for negation - eval "m{$_}"; ## check regex syntax - if ($@) { - ++$bad_regexs; - carp qq{Bad regular expression /$_/ in "$section_spec": $@\n}; - } - else { - ## Add the forward and rear anchors (and put the negator back) - $_ = '^' . $_ unless (/^\^/); - $_ = $_ . '$' unless (/\$$/); - $_ = '!' . $_ if ($negated); - } - } - return (! $bad_regexs) ? [ @regexs ] : undef; -} - -##--------------------------------------------------------------------------- - -=begin _PRIVATE_ - -=head2 $self->{_SECTION_HEADINGS} - -A reference to an array of the current section heading titles for each -heading level (note that the first heading level title is at index 0). - -=end _PRIVATE_ - -=cut - -##--------------------------------------------------------------------------- - -=begin _PRIVATE_ - -=head2 $self->{_SELECTED_SECTIONS} - -A reference to an array of references to arrays. Each subarray is a list -of anchored regular expressions (preceded by a "!" if the expression is to -be negated). The index of the expression in the subarray should correspond -to the index of the heading title in C<$self-E<gt>{_SECTION_HEADINGS}> -that it is to be matched against. - -=end _PRIVATE_ - -=cut - -############################################################################# - -=head1 SEE ALSO - -L<Pod::Parser> - -=head1 AUTHOR - -Please report bugs using L<http://rt.cpan.org>. - -Brad Appleton E<lt>bradapp@enteract.comE<gt> - -Based on code for B<pod2text> written by -Tom Christiansen E<lt>tchrist@mox.perl.comE<gt> - -B<Pod::Select> is part of the L<Pod::Parser> distribution. - -=cut - -1; -# vim: ts=4 sw=4 et +#############################################################################
+# Pod/Select.pm -- function to select portions of POD docs
+#
+# Copyright (C) 1996-2000 by Bradford Appleton. All rights reserved.
+# This file is part of "PodParser". PodParser is free software;
+# you can redistribute it and/or modify it under the same terms
+# as Perl itself.
+#############################################################################
+
+package Pod::Select;
+use strict;
+
+use vars qw($VERSION @ISA @EXPORT $MAX_HEADING_LEVEL %myData @section_headings @selected_sections);
+$VERSION = '1.60'; ## Current version of this package
+require 5.005; ## requires this Perl version or later
+
+#############################################################################
+
+=head1 NAME
+
+Pod::Select, podselect() - extract selected sections of POD from input
+
+=head1 SYNOPSIS
+
+ use Pod::Select;
+
+ ## Select all the POD sections for each file in @filelist
+ ## and print the result on standard output.
+ podselect(@filelist);
+
+ ## Same as above, but write to tmp.out
+ podselect({-output => "tmp.out"}, @filelist):
+
+ ## Select from the given filelist, only those POD sections that are
+ ## within a 1st level section named any of: NAME, SYNOPSIS, OPTIONS.
+ podselect({-sections => ["NAME|SYNOPSIS", "OPTIONS"]}, @filelist):
+
+ ## Select the "DESCRIPTION" section of the PODs from STDIN and write
+ ## the result to STDERR.
+ podselect({-output => ">&STDERR", -sections => ["DESCRIPTION"]}, \*STDIN);
+
+or
+
+ use Pod::Select;
+
+ ## Create a parser object for selecting POD sections from the input
+ $parser = new Pod::Select();
+
+ ## Select all the POD sections for each file in @filelist
+ ## and print the result to tmp.out.
+ $parser->parse_from_file("<&STDIN", "tmp.out");
+
+ ## Select from the given filelist, only those POD sections that are
+ ## within a 1st level section named any of: NAME, SYNOPSIS, OPTIONS.
+ $parser->select("NAME|SYNOPSIS", "OPTIONS");
+ for (@filelist) { $parser->parse_from_file($_); }
+
+ ## Select the "DESCRIPTION" and "SEE ALSO" sections of the PODs from
+ ## STDIN and write the result to STDERR.
+ $parser->select("DESCRIPTION");
+ $parser->add_selection("SEE ALSO");
+ $parser->parse_from_filehandle(\*STDIN, \*STDERR);
+
+=head1 REQUIRES
+
+perl5.005, Pod::Parser, Exporter, Carp
+
+=head1 EXPORTS
+
+podselect()
+
+=head1 DESCRIPTION
+
+B<podselect()> is a function which will extract specified sections of
+pod documentation from an input stream. This ability is provided by the
+B<Pod::Select> module which is a subclass of B<Pod::Parser>.
+B<Pod::Select> provides a method named B<select()> to specify the set of
+POD sections to select for processing/printing. B<podselect()> merely
+creates a B<Pod::Select> object and then invokes the B<podselect()>
+followed by B<parse_from_file()>.
+
+=head1 SECTION SPECIFICATIONS
+
+B<podselect()> and B<Pod::Select::select()> may be given one or more
+"section specifications" to restrict the text processed to only the
+desired set of sections and their corresponding subsections. A section
+specification is a string containing one or more Perl-style regular
+expressions separated by forward slashes ("/"). If you need to use a
+forward slash literally within a section title you can escape it with a
+backslash ("\/").
+
+The formal syntax of a section specification is:
+
+=over 4
+
+=item *
+
+I<head1-title-regex>/I<head2-title-regex>/...
+
+=back
+
+Any omitted or empty regular expressions will default to ".*".
+Please note that each regular expression given is implicitly
+anchored by adding "^" and "$" to the beginning and end. Also, if a
+given regular expression starts with a "!" character, then the
+expression is I<negated> (so C<!foo> would match anything I<except>
+C<foo>).
+
+Some example section specifications follow.
+
+=over 4
+
+=item *
+
+Match the C<NAME> and C<SYNOPSIS> sections and all of their subsections:
+
+C<NAME|SYNOPSIS>
+
+=item *
+
+Match only the C<Question> and C<Answer> subsections of the C<DESCRIPTION>
+section:
+
+C<DESCRIPTION/Question|Answer>
+
+=item *
+
+Match the C<Comments> subsection of I<all> sections:
+
+C</Comments>
+
+=item *
+
+Match all subsections of C<DESCRIPTION> I<except> for C<Comments>:
+
+C<DESCRIPTION/!Comments>
+
+=item *
+
+Match the C<DESCRIPTION> section but do I<not> match any of its subsections:
+
+C<DESCRIPTION/!.+>
+
+=item *
+
+Match all top level sections but none of their subsections:
+
+C</!.+>
+
+=back
+
+=begin _NOT_IMPLEMENTED_
+
+=head1 RANGE SPECIFICATIONS
+
+B<podselect()> and B<Pod::Select::select()> may be given one or more
+"range specifications" to restrict the text processed to only the
+desired ranges of paragraphs in the desired set of sections. A range
+specification is a string containing a single Perl-style regular
+expression (a regex), or else two Perl-style regular expressions
+(regexs) separated by a ".." (Perl's "range" operator is "..").
+The regexs in a range specification are delimited by forward slashes
+("/"). If you need to use a forward slash literally within a regex you
+can escape it with a backslash ("\/").
+
+The formal syntax of a range specification is:
+
+=over 4
+
+=item *
+
+/I<start-range-regex>/[../I<end-range-regex>/]
+
+=back
+
+Where each the item inside square brackets (the ".." followed by the
+end-range-regex) is optional. Each "range-regex" is of the form:
+
+ =cmd-expr text-expr
+
+Where I<cmd-expr> is intended to match the name of one or more POD
+commands, and I<text-expr> is intended to match the paragraph text for
+the command. If a range-regex is supposed to match a POD command, then
+the first character of the regex (the one after the initial '/')
+absolutely I<must> be a single '=' character; it may not be anything
+else (not even a regex meta-character) if it is supposed to match
+against the name of a POD command.
+
+If no I<=cmd-expr> is given then the text-expr will be matched against
+plain textblocks unless it is preceded by a space, in which case it is
+matched against verbatim text-blocks. If no I<text-expr> is given then
+only the command-portion of the paragraph is matched against.
+
+Note that these two expressions are each implicitly anchored. This
+means that when matching against the command-name, there will be an
+implicit '^' and '$' around the given I<=cmd-expr>; and when matching
+against the paragraph text there will be an implicit '\A' and '\Z'
+around the given I<text-expr>.
+
+Unlike with section-specs, the '!' character does I<not> have any special
+meaning (negation or otherwise) at the beginning of a range-spec!
+
+Some example range specifications follow.
+
+=over 4
+
+=item
+Match all C<=for html> paragraphs:
+
+C</=for html/>
+
+=item
+Match all paragraphs between C<=begin html> and C<=end html>
+(note that this will I<not> work correctly if such sections
+are nested):
+
+C</=begin html/../=end html/>
+
+=item
+Match all paragraphs between the given C<=item> name until the end of the
+current section:
+
+C</=item mine/../=head\d/>
+
+=item
+Match all paragraphs between the given C<=item> until the next item, or
+until the end of the itemized list (note that this will I<not> work as
+desired if the item contains an itemized list nested within it):
+
+C</=item mine/../=(item|back)/>
+
+=back
+
+=end _NOT_IMPLEMENTED_
+
+=cut
+
+#############################################################################
+
+#use diagnostics;
+use Carp;
+use Pod::Parser 1.04;
+
+@ISA = qw(Pod::Parser);
+@EXPORT = qw(&podselect);
+
+## Maximum number of heading levels supported for '=headN' directives
+*MAX_HEADING_LEVEL = \3;
+
+#############################################################################
+
+=head1 OBJECT METHODS
+
+The following methods are provided in this module. Each one takes a
+reference to the object itself as an implicit first parameter.
+
+=cut
+
+##---------------------------------------------------------------------------
+
+## =begin _PRIVATE_
+##
+## =head1 B<_init_headings()>
+##
+## Initialize the current set of active section headings.
+##
+## =cut
+##
+## =end _PRIVATE_
+
+sub _init_headings {
+ my $self = shift;
+ local *myData = $self;
+
+ ## Initialize current section heading titles if necessary
+ unless (defined $myData{_SECTION_HEADINGS}) {
+ local *section_headings = $myData{_SECTION_HEADINGS} = [];
+ for (my $i = 0; $i < $MAX_HEADING_LEVEL; ++$i) {
+ $section_headings[$i] = '';
+ }
+ }
+}
+
+##---------------------------------------------------------------------------
+
+=head1 B<curr_headings()>
+
+ ($head1, $head2, $head3, ...) = $parser->curr_headings();
+ $head1 = $parser->curr_headings(1);
+
+This method returns a list of the currently active section headings and
+subheadings in the document being parsed. The list of headings returned
+corresponds to the most recently parsed paragraph of the input.
+
+If an argument is given, it must correspond to the desired section
+heading number, in which case only the specified section heading is
+returned. If there is no current section heading at the specified
+level, then C<undef> is returned.
+
+=cut
+
+sub curr_headings {
+ my $self = shift;
+ $self->_init_headings() unless (defined $self->{_SECTION_HEADINGS});
+ my @headings = @{ $self->{_SECTION_HEADINGS} };
+ return (@_ > 0 and $_[0] =~ /^\d+$/) ? $headings[$_[0] - 1] : @headings;
+}
+
+##---------------------------------------------------------------------------
+
+=head1 B<select()>
+
+ $parser->select($section_spec1,$section_spec2,...);
+
+This method is used to select the particular sections and subsections of
+POD documentation that are to be printed and/or processed. The existing
+set of selected sections is I<replaced> with the given set of sections.
+See B<add_selection()> for adding to the current set of selected
+sections.
+
+Each of the C<$section_spec> arguments should be a section specification
+as described in L<"SECTION SPECIFICATIONS">. The section specifications
+are parsed by this method and the resulting regular expressions are
+stored in the invoking object.
+
+If no C<$section_spec> arguments are given, then the existing set of
+selected sections is cleared out (which means C<all> sections will be
+processed).
+
+This method should I<not> normally be overridden by subclasses.
+
+=cut
+
+sub select {
+ my ($self, @sections) = @_;
+ local *myData = $self;
+ local $_;
+
+### NEED TO DISCERN A SECTION-SPEC FROM A RANGE-SPEC (look for m{^/.+/$}?)
+
+ ##---------------------------------------------------------------------
+ ## The following is a blatant hack for backward compatibility, and for
+ ## implementing add_selection(). If the *first* *argument* is the
+ ## string "+", then the remaining section specifications are *added*
+ ## to the current set of selections; otherwise the given section
+ ## specifications will *replace* the current set of selections.
+ ##
+ ## This should probably be fixed someday, but for the present time,
+ ## it seems incredibly unlikely that "+" would ever correspond to
+ ## a legitimate section heading
+ ##---------------------------------------------------------------------
+ my $add = ($sections[0] eq '+') ? shift(@sections) : '';
+
+ ## Reset the set of sections to use
+ unless (@sections) {
+ delete $myData{_SELECTED_SECTIONS} unless ($add);
+ return;
+ }
+ $myData{_SELECTED_SECTIONS} = []
+ unless ($add && exists $myData{_SELECTED_SECTIONS});
+ local *selected_sections = $myData{_SELECTED_SECTIONS};
+
+ ## Compile each spec
+ for my $spec (@sections) {
+ if ( defined($_ = _compile_section_spec($spec)) ) {
+ ## Store them in our sections array
+ push(@selected_sections, $_);
+ }
+ else {
+ carp qq{Ignoring section spec "$spec"!\n};
+ }
+ }
+}
+
+##---------------------------------------------------------------------------
+
+=head1 B<add_selection()>
+
+ $parser->add_selection($section_spec1,$section_spec2,...);
+
+This method is used to add to the currently selected sections and
+subsections of POD documentation that are to be printed and/or
+processed. See <select()> for replacing the currently selected sections.
+
+Each of the C<$section_spec> arguments should be a section specification
+as described in L<"SECTION SPECIFICATIONS">. The section specifications
+are parsed by this method and the resulting regular expressions are
+stored in the invoking object.
+
+This method should I<not> normally be overridden by subclasses.
+
+=cut
+
+sub add_selection {
+ my $self = shift;
+ return $self->select('+', @_);
+}
+
+##---------------------------------------------------------------------------
+
+=head1 B<clear_selections()>
+
+ $parser->clear_selections();
+
+This method takes no arguments, it has the exact same effect as invoking
+<select()> with no arguments.
+
+=cut
+
+sub clear_selections {
+ my $self = shift;
+ return $self->select();
+}
+
+##---------------------------------------------------------------------------
+
+=head1 B<match_section()>
+
+ $boolean = $parser->match_section($heading1,$heading2,...);
+
+Returns a value of true if the given section and subsection heading
+titles match any of the currently selected section specifications in
+effect from prior calls to B<select()> and B<add_selection()> (or if
+there are no explicitly selected/deselected sections).
+
+The arguments C<$heading1>, C<$heading2>, etc. are the heading titles of
+the corresponding sections, subsections, etc. to try and match. If
+C<$headingN> is omitted then it defaults to the current corresponding
+section heading title in the input.
+
+This method should I<not> normally be overridden by subclasses.
+
+=cut
+
+sub match_section {
+ my $self = shift;
+ my (@headings) = @_;
+ local *myData = $self;
+
+ ## Return true if no restrictions were explicitly specified
+ my $selections = (exists $myData{_SELECTED_SECTIONS})
+ ? $myData{_SELECTED_SECTIONS} : undef;
+ return 1 unless ((defined $selections) && @{$selections});
+
+ ## Default any unspecified sections to the current one
+ my @current_headings = $self->curr_headings();
+ for (my $i = 0; $i < $MAX_HEADING_LEVEL; ++$i) {
+ (defined $headings[$i]) or $headings[$i] = $current_headings[$i];
+ }
+
+ ## Look for a match against the specified section expressions
+ for my $section_spec ( @{$selections} ) {
+ ##------------------------------------------------------
+ ## Each portion of this spec must match in order for
+ ## the spec to be matched. So we will start with a
+ ## match-value of 'true' and logically 'and' it with
+ ## the results of matching a given element of the spec.
+ ##------------------------------------------------------
+ my $match = 1;
+ for (my $i = 0; $i < $MAX_HEADING_LEVEL; ++$i) {
+ my $regex = $section_spec->[$i];
+ my $negated = ($regex =~ s/^\!//);
+ $match &= ($negated ? ($headings[$i] !~ /${regex}/)
+ : ($headings[$i] =~ /${regex}/));
+ last unless ($match);
+ }
+ return 1 if ($match);
+ }
+ return 0; ## no match
+}
+
+##---------------------------------------------------------------------------
+
+=head1 B<is_selected()>
+
+ $boolean = $parser->is_selected($paragraph);
+
+This method is used to determine if the block of text given in
+C<$paragraph> falls within the currently selected set of POD sections
+and subsections to be printed or processed. This method is also
+responsible for keeping track of the current input section and
+subsections. It is assumed that C<$paragraph> is the most recently read
+(but not yet processed) input paragraph.
+
+The value returned will be true if the C<$paragraph> and the rest of the
+text in the same section as C<$paragraph> should be selected (included)
+for processing; otherwise a false value is returned.
+
+=cut
+
+sub is_selected {
+ my ($self, $paragraph) = @_;
+ local $_;
+ local *myData = $self;
+
+ $self->_init_headings() unless (defined $myData{_SECTION_HEADINGS});
+
+ ## Keep track of current sections levels and headings
+ $_ = $paragraph;
+ if (/^=((?:sub)*)(?:head(?:ing)?|sec(?:tion)?)(\d*)\s+(.*?)\s*$/)
+ {
+ ## This is a section heading command
+ my ($level, $heading) = ($2, $3);
+ $level = 1 + (length($1) / 3) if ((! length $level) || (length $1));
+ ## Reset the current section heading at this level
+ $myData{_SECTION_HEADINGS}->[$level - 1] = $heading;
+ ## Reset subsection headings of this one to empty
+ for (my $i = $level; $i < $MAX_HEADING_LEVEL; ++$i) {
+ $myData{_SECTION_HEADINGS}->[$i] = '';
+ }
+ }
+
+ return $self->match_section();
+}
+
+#############################################################################
+
+=head1 EXPORTED FUNCTIONS
+
+The following functions are exported by this module. Please note that
+these are functions (not methods) and therefore C<do not> take an
+implicit first argument.
+
+=cut
+
+##---------------------------------------------------------------------------
+
+=head1 B<podselect()>
+
+ podselect(\%options,@filelist);
+
+B<podselect> will print the raw (untranslated) POD paragraphs of all
+POD sections in the given input files specified by C<@filelist>
+according to the given options.
+
+If any argument to B<podselect> is a reference to a hash
+(associative array) then the values with the following keys are
+processed as follows:
+
+=over 4
+
+=item B<-output>
+
+A string corresponding to the desired output file (or ">&STDOUT"
+or ">&STDERR"). The default is to use standard output.
+
+=item B<-sections>
+
+A reference to an array of sections specifications (as described in
+L<"SECTION SPECIFICATIONS">) which indicate the desired set of POD
+sections and subsections to be selected from input. If no section
+specifications are given, then all sections of the PODs are used.
+
+=begin _NOT_IMPLEMENTED_
+
+=item B<-ranges>
+
+A reference to an array of range specifications (as described in
+L<"RANGE SPECIFICATIONS">) which indicate the desired range of POD
+paragraphs to be selected from the desired input sections. If no range
+specifications are given, then all paragraphs of the desired sections
+are used.
+
+=end _NOT_IMPLEMENTED_
+
+=back
+
+All other arguments should correspond to the names of input files
+containing POD sections. A file name of "-" or "<&STDIN" will
+be interpreted to mean standard input (which is the default if no
+filenames are given).
+
+=cut
+
+sub podselect {
+ my(@argv) = @_;
+ my %defaults = ();
+ my $pod_parser = new Pod::Select(%defaults);
+ my $num_inputs = 0;
+ my $output = '>&STDOUT';
+ my %opts;
+ local $_;
+ for (@argv) {
+ if (ref($_)) {
+ next unless (ref($_) eq 'HASH');
+ %opts = (%defaults, %{$_});
+
+ ##-------------------------------------------------------------
+ ## Need this for backward compatibility since we formerly used
+ ## options that were all uppercase words rather than ones that
+ ## looked like Unix command-line options.
+ ## to be uppercase keywords)
+ ##-------------------------------------------------------------
+ %opts = map {
+ my ($key, $val) = (lc $_, $opts{$_});
+ $key =~ s/^(?=\w)/-/;
+ $key =~ /^-se[cl]/ and $key = '-sections';
+ #! $key eq '-range' and $key .= 's';
+ ($key => $val);
+ } (keys %opts);
+
+ ## Process the options
+ (exists $opts{'-output'}) and $output = $opts{'-output'};
+
+ ## Select the desired sections
+ $pod_parser->select(@{ $opts{'-sections'} })
+ if ( (defined $opts{'-sections'})
+ && ((ref $opts{'-sections'}) eq 'ARRAY') );
+
+ #! ## Select the desired paragraph ranges
+ #! $pod_parser->select(@{ $opts{'-ranges'} })
+ #! if ( (defined $opts{'-ranges'})
+ #! && ((ref $opts{'-ranges'}) eq 'ARRAY') );
+ }
+ else {
+ $pod_parser->parse_from_file($_, $output);
+ ++$num_inputs;
+ }
+ }
+ $pod_parser->parse_from_file('-') unless ($num_inputs > 0);
+}
+
+#############################################################################
+
+=head1 PRIVATE METHODS AND DATA
+
+B<Pod::Select> makes uses a number of internal methods and data fields
+which clients should not need to see or use. For the sake of avoiding
+name collisions with client data and methods, these methods and fields
+are briefly discussed here. Determined hackers may obtain further
+information about them by reading the B<Pod::Select> source code.
+
+Private data fields are stored in the hash-object whose reference is
+returned by the B<new()> constructor for this class. The names of all
+private methods and data-fields used by B<Pod::Select> begin with a
+prefix of "_" and match the regular expression C</^_\w+$/>.
+
+=cut
+
+##---------------------------------------------------------------------------
+
+=begin _PRIVATE_
+
+=head1 B<_compile_section_spec()>
+
+ $listref = $parser->_compile_section_spec($section_spec);
+
+This function (note it is a function and I<not> a method) takes a
+section specification (as described in L<"SECTION SPECIFICATIONS">)
+given in C<$section_sepc>, and compiles it into a list of regular
+expressions. If C<$section_spec> has no syntax errors, then a reference
+to the list (array) of corresponding regular expressions is returned;
+otherwise C<undef> is returned and an error message is printed (using
+B<carp>) for each invalid regex.
+
+=end _PRIVATE_
+
+=cut
+
+sub _compile_section_spec {
+ my ($section_spec) = @_;
+ my (@regexs, $negated);
+
+ ## Compile the spec into a list of regexs
+ local $_ = $section_spec;
+ s{\\\\}{\001}g; ## handle escaped backward slashes
+ s{\\/}{\002}g; ## handle escaped forward slashes
+
+ ## Parse the regexs for the heading titles
+ @regexs = split(/\//, $_, $MAX_HEADING_LEVEL);
+
+ ## Set default regex for ommitted levels
+ for (my $i = 0; $i < $MAX_HEADING_LEVEL; ++$i) {
+ $regexs[$i] = '.*' unless ((defined $regexs[$i])
+ && (length $regexs[$i]));
+ }
+ ## Modify the regexs as needed and validate their syntax
+ my $bad_regexs = 0;
+ for (@regexs) {
+ $_ .= '.+' if ($_ eq '!');
+ s{\001}{\\\\}g; ## restore escaped backward slashes
+ s{\002}{\\/}g; ## restore escaped forward slashes
+ $negated = s/^\!//; ## check for negation
+ eval "m{$_}"; ## check regex syntax
+ if ($@) {
+ ++$bad_regexs;
+ carp qq{Bad regular expression /$_/ in "$section_spec": $@\n};
+ }
+ else {
+ ## Add the forward and rear anchors (and put the negator back)
+ $_ = '^' . $_ unless (/^\^/);
+ $_ = $_ . '$' unless (/\$$/);
+ $_ = '!' . $_ if ($negated);
+ }
+ }
+ return (! $bad_regexs) ? [ @regexs ] : undef;
+}
+
+##---------------------------------------------------------------------------
+
+=begin _PRIVATE_
+
+=head2 $self->{_SECTION_HEADINGS}
+
+A reference to an array of the current section heading titles for each
+heading level (note that the first heading level title is at index 0).
+
+=end _PRIVATE_
+
+=cut
+
+##---------------------------------------------------------------------------
+
+=begin _PRIVATE_
+
+=head2 $self->{_SELECTED_SECTIONS}
+
+A reference to an array of references to arrays. Each subarray is a list
+of anchored regular expressions (preceded by a "!" if the expression is to
+be negated). The index of the expression in the subarray should correspond
+to the index of the heading title in C<$self-E<gt>{_SECTION_HEADINGS}>
+that it is to be matched against.
+
+=end _PRIVATE_
+
+=cut
+
+#############################################################################
+
+=head1 SEE ALSO
+
+L<Pod::Parser>
+
+=head1 AUTHOR
+
+Please report bugs using L<http://rt.cpan.org>.
+
+Brad Appleton E<lt>bradapp@enteract.comE<gt>
+
+Based on code for B<pod2text> written by
+Tom Christiansen E<lt>tchrist@mox.perl.comE<gt>
+
+B<Pod::Select> is part of the L<Pod::Parser> distribution.
+
+=cut
+
+1;
+# vim: ts=4 sw=4 et
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