xref: /openbsd-src/gnu/usr.bin/perl/cpan/podlators/lib/Pod/Text.pm (revision d13be5d47e4149db2549a9828e244d59dbc43f15)
1# Pod::Text -- Convert POD data to formatted ASCII text.
2#
3# Copyright 1999, 2000, 2001, 2002, 2004, 2006, 2008, 2009
4#     Russ Allbery <rra@stanford.edu>
5#
6# This program is free software; you may redistribute it and/or modify it
7# under the same terms as Perl itself.
8#
9# This module converts POD to formatted text.  It replaces the old Pod::Text
10# module that came with versions of Perl prior to 5.6.0 and attempts to match
11# its output except for some specific circumstances where other decisions
12# seemed to produce better output.  It uses Pod::Parser and is designed to be
13# very easy to subclass.
14#
15# Perl core hackers, please note that this module is also separately
16# maintained outside of the Perl core as part of the podlators.  Please send
17# me any patches at the address above in addition to sending them to the
18# standard Perl mailing lists.
19
20##############################################################################
21# Modules and declarations
22##############################################################################
23
24package Pod::Text;
25
26require 5.004;
27
28use strict;
29use vars qw(@ISA @EXPORT %ESCAPES $VERSION);
30
31use Carp qw(carp croak);
32use Exporter ();
33use Pod::Simple ();
34
35@ISA = qw(Pod::Simple Exporter);
36
37# We have to export pod2text for backward compatibility.
38@EXPORT = qw(pod2text);
39
40$VERSION = '3.14';
41
42##############################################################################
43# Initialization
44##############################################################################
45
46# This function handles code blocks.  It's registered as a callback to
47# Pod::Simple and therefore doesn't work as a regular method call, but all it
48# does is call output_code with the line.
49sub handle_code {
50    my ($line, $number, $parser) = @_;
51    $parser->output_code ($line . "\n");
52}
53
54# Initialize the object and set various Pod::Simple options that we need.
55# Here, we also process any additional options passed to the constructor or
56# set up defaults if none were given.  Note that all internal object keys are
57# in all-caps, reserving all lower-case object keys for Pod::Simple and user
58# arguments.
59sub new {
60    my $class = shift;
61    my $self = $class->SUPER::new;
62
63    # Tell Pod::Simple to handle S<> by automatically inserting &nbsp;.
64    $self->nbsp_for_S (1);
65
66    # Tell Pod::Simple to keep whitespace whenever possible.
67    if ($self->can ('preserve_whitespace')) {
68        $self->preserve_whitespace (1);
69    } else {
70        $self->fullstop_space_harden (1);
71    }
72
73    # The =for and =begin targets that we accept.
74    $self->accept_targets (qw/text TEXT/);
75
76    # Ensure that contiguous blocks of code are merged together.  Otherwise,
77    # some of the guesswork heuristics don't work right.
78    $self->merge_text (1);
79
80    # Pod::Simple doesn't do anything useful with our arguments, but we want
81    # to put them in our object as hash keys and values.  This could cause
82    # problems if we ever clash with Pod::Simple's own internal class
83    # variables.
84    my %opts = @_;
85    my @opts = map { ("opt_$_", $opts{$_}) } keys %opts;
86    %$self = (%$self, @opts);
87
88    # Send errors to stderr if requested.
89    if ($$self{opt_stderr}) {
90        $self->no_errata_section (1);
91        $self->complain_stderr (1);
92        delete $$self{opt_stderr};
93    }
94
95    # Initialize various things from our parameters.
96    $$self{opt_alt}      = 0  unless defined $$self{opt_alt};
97    $$self{opt_indent}   = 4  unless defined $$self{opt_indent};
98    $$self{opt_margin}   = 0  unless defined $$self{opt_margin};
99    $$self{opt_loose}    = 0  unless defined $$self{opt_loose};
100    $$self{opt_sentence} = 0  unless defined $$self{opt_sentence};
101    $$self{opt_width}    = 76 unless defined $$self{opt_width};
102
103    # Figure out what quotes we'll be using for C<> text.
104    $$self{opt_quotes} ||= '"';
105    if ($$self{opt_quotes} eq 'none') {
106        $$self{LQUOTE} = $$self{RQUOTE} = '';
107    } elsif (length ($$self{opt_quotes}) == 1) {
108        $$self{LQUOTE} = $$self{RQUOTE} = $$self{opt_quotes};
109    } elsif ($$self{opt_quotes} =~ /^(.)(.)$/
110             || $$self{opt_quotes} =~ /^(..)(..)$/) {
111        $$self{LQUOTE} = $1;
112        $$self{RQUOTE} = $2;
113    } else {
114        croak qq(Invalid quote specification "$$self{opt_quotes}");
115    }
116
117    # If requested, do something with the non-POD text.
118    $self->code_handler (\&handle_code) if $$self{opt_code};
119
120    # Return the created object.
121    return $self;
122}
123
124##############################################################################
125# Core parsing
126##############################################################################
127
128# This is the glue that connects the code below with Pod::Simple itself.  The
129# goal is to convert the event stream coming from the POD parser into method
130# calls to handlers once the complete content of a tag has been seen.  Each
131# paragraph or POD command will have textual content associated with it, and
132# as soon as all of a paragraph or POD command has been seen, that content
133# will be passed in to the corresponding method for handling that type of
134# object.  The exceptions are handlers for lists, which have opening tag
135# handlers and closing tag handlers that will be called right away.
136#
137# The internal hash key PENDING is used to store the contents of a tag until
138# all of it has been seen.  It holds a stack of open tags, each one
139# represented by a tuple of the attributes hash for the tag and the contents
140# of the tag.
141
142# Add a block of text to the contents of the current node, formatting it
143# according to the current formatting instructions as we do.
144sub _handle_text {
145    my ($self, $text) = @_;
146    my $tag = $$self{PENDING}[-1];
147    $$tag[1] .= $text;
148}
149
150# Given an element name, get the corresponding method name.
151sub method_for_element {
152    my ($self, $element) = @_;
153    $element =~ tr/-/_/;
154    $element =~ tr/A-Z/a-z/;
155    $element =~ tr/_a-z0-9//cd;
156    return $element;
157}
158
159# Handle the start of a new element.  If cmd_element is defined, assume that
160# we need to collect the entire tree for this element before passing it to the
161# element method, and create a new tree into which we'll collect blocks of
162# text and nested elements.  Otherwise, if start_element is defined, call it.
163sub _handle_element_start {
164    my ($self, $element, $attrs) = @_;
165    my $method = $self->method_for_element ($element);
166
167    # If we have a command handler, we need to accumulate the contents of the
168    # tag before calling it.
169    if ($self->can ("cmd_$method")) {
170        push (@{ $$self{PENDING} }, [ $attrs, '' ]);
171    } elsif ($self->can ("start_$method")) {
172        my $method = 'start_' . $method;
173        $self->$method ($attrs, '');
174    }
175}
176
177# Handle the end of an element.  If we had a cmd_ method for this element,
178# this is where we pass along the text that we've accumulated.  Otherwise, if
179# we have an end_ method for the element, call that.
180sub _handle_element_end {
181    my ($self, $element) = @_;
182    my $method = $self->method_for_element ($element);
183
184    # If we have a command handler, pull off the pending text and pass it to
185    # the handler along with the saved attribute hash.
186    if ($self->can ("cmd_$method")) {
187        my $tag = pop @{ $$self{PENDING} };
188        my $method = 'cmd_' . $method;
189        my $text = $self->$method (@$tag);
190        if (defined $text) {
191            if (@{ $$self{PENDING} } > 1) {
192                $$self{PENDING}[-1][1] .= $text;
193            } else {
194                $self->output ($text);
195            }
196        }
197    } elsif ($self->can ("end_$method")) {
198        my $method = 'end_' . $method;
199        $self->$method ();
200    }
201}
202
203##############################################################################
204# Output formatting
205##############################################################################
206
207# Wrap a line, indenting by the current left margin.  We can't use Text::Wrap
208# because it plays games with tabs.  We can't use formline, even though we'd
209# really like to, because it screws up non-printing characters.  So we have to
210# do the wrapping ourselves.
211sub wrap {
212    my $self = shift;
213    local $_ = shift;
214    my $output = '';
215    my $spaces = ' ' x $$self{MARGIN};
216    my $width = $$self{opt_width} - $$self{MARGIN};
217    while (length > $width) {
218        if (s/^([^\n]{0,$width})\s+// || s/^([^\n]{$width})//) {
219            $output .= $spaces . $1 . "\n";
220        } else {
221            last;
222        }
223    }
224    $output .= $spaces . $_;
225    $output =~ s/\s+$/\n\n/;
226    return $output;
227}
228
229# Reformat a paragraph of text for the current margin.  Takes the text to
230# reformat and returns the formatted text.
231sub reformat {
232    my $self = shift;
233    local $_ = shift;
234
235    # If we're trying to preserve two spaces after sentences, do some munging
236    # to support that.  Otherwise, smash all repeated whitespace.
237    if ($$self{opt_sentence}) {
238        s/ +$//mg;
239        s/\.\n/. \n/g;
240        s/\n/ /g;
241        s/   +/  /g;
242    } else {
243        s/\s+/ /g;
244    }
245    return $self->wrap ($_);
246}
247
248# Output text to the output device.  Replace non-breaking spaces with spaces
249# and soft hyphens with nothing, and then try to fix the output encoding if
250# necessary to match the input encoding unless UTF-8 output is forced.  This
251# preserves the traditional pass-through behavior of Pod::Text.
252sub output {
253    my ($self, $text) = @_;
254    $text =~ tr/\240\255/ /d;
255    unless ($$self{opt_utf8} || $$self{CHECKED_ENCODING}) {
256        my $encoding = $$self{encoding} || '';
257        if ($encoding) {
258            eval { binmode ($$self{output_fh}, ":encoding($encoding)") };
259        }
260        $$self{CHECKED_ENCODING} = 1;
261    }
262    print { $$self{output_fh} } $text;
263}
264
265# Output a block of code (something that isn't part of the POD text).  Called
266# by preprocess_paragraph only if we were given the code option.  Exists here
267# only so that it can be overridden by subclasses.
268sub output_code { $_[0]->output ($_[1]) }
269
270##############################################################################
271# Document initialization
272##############################################################################
273
274# Set up various things that have to be initialized on a per-document basis.
275sub start_document {
276    my $self = shift;
277    my $margin = $$self{opt_indent} + $$self{opt_margin};
278
279    # Initialize a few per-document variables.
280    $$self{INDENTS} = [];       # Stack of indentations.
281    $$self{MARGIN}  = $margin;  # Default left margin.
282    $$self{PENDING} = [[]];     # Pending output.
283
284    # We have to redo encoding handling for each document.
285    delete $$self{CHECKED_ENCODING};
286
287    # If we were given the utf8 option, set an output encoding on our file
288    # handle.  Wrap in an eval in case we're using a version of Perl too old
289    # to understand this.
290    #
291    # This is evil because it changes the global state of a file handle that
292    # we may not own.  However, we can't just blindly encode all output, since
293    # there may be a pre-applied output encoding (such as from PERL_UNICODE)
294    # and then we would double-encode.  This seems to be the least bad
295    # approach.
296    if ($$self{opt_utf8}) {
297        eval { binmode ($$self{output_fh}, ':encoding(UTF-8)') };
298    }
299
300    return '';
301}
302
303##############################################################################
304# Text blocks
305##############################################################################
306
307# Intended for subclasses to override, this method returns text with any
308# non-printing formatting codes stripped out so that length() correctly
309# returns the length of the text.  For basic Pod::Text, it does nothing.
310sub strip_format {
311    my ($self, $string) = @_;
312    return $string;
313}
314
315# This method is called whenever an =item command is complete (in other words,
316# we've seen its associated paragraph or know for certain that it doesn't have
317# one).  It gets the paragraph associated with the item as an argument.  If
318# that argument is empty, just output the item tag; if it contains a newline,
319# output the item tag followed by the newline.  Otherwise, see if there's
320# enough room for us to output the item tag in the margin of the text or if we
321# have to put it on a separate line.
322sub item {
323    my ($self, $text) = @_;
324    my $tag = $$self{ITEM};
325    unless (defined $tag) {
326        carp "Item called without tag";
327        return;
328    }
329    undef $$self{ITEM};
330
331    # Calculate the indentation and margin.  $fits is set to true if the tag
332    # will fit into the margin of the paragraph given our indentation level.
333    my $indent = $$self{INDENTS}[-1];
334    $indent = $$self{opt_indent} unless defined $indent;
335    my $margin = ' ' x $$self{opt_margin};
336    my $tag_length = length ($self->strip_format ($tag));
337    my $fits = ($$self{MARGIN} - $indent >= $tag_length + 1);
338
339    # If the tag doesn't fit, or if we have no associated text, print out the
340    # tag separately.  Otherwise, put the tag in the margin of the paragraph.
341    if (!$text || $text =~ /^\s+$/ || !$fits) {
342        my $realindent = $$self{MARGIN};
343        $$self{MARGIN} = $indent;
344        my $output = $self->reformat ($tag);
345        $output =~ s/^$margin /$margin:/ if ($$self{opt_alt} && $indent > 0);
346        $output =~ s/\n*$/\n/;
347
348        # If the text is just whitespace, we have an empty item paragraph;
349        # this can result from =over/=item/=back without any intermixed
350        # paragraphs.  Insert some whitespace to keep the =item from merging
351        # into the next paragraph.
352        $output .= "\n" if $text && $text =~ /^\s*$/;
353
354        $self->output ($output);
355        $$self{MARGIN} = $realindent;
356        $self->output ($self->reformat ($text)) if ($text && $text =~ /\S/);
357    } else {
358        my $space = ' ' x $indent;
359        $space =~ s/^$margin /$margin:/ if $$self{opt_alt};
360        $text = $self->reformat ($text);
361        $text =~ s/^$margin /$margin:/ if ($$self{opt_alt} && $indent > 0);
362        my $tagspace = ' ' x $tag_length;
363        $text =~ s/^($space)$tagspace/$1$tag/ or warn "Bizarre space in item";
364        $self->output ($text);
365    }
366}
367
368# Handle a basic block of text.  The only tricky thing here is that if there
369# is a pending item tag, we need to format this as an item paragraph.
370sub cmd_para {
371    my ($self, $attrs, $text) = @_;
372    $text =~ s/\s+$/\n/;
373    if (defined $$self{ITEM}) {
374        $self->item ($text . "\n");
375    } else {
376        $self->output ($self->reformat ($text . "\n"));
377    }
378    return '';
379}
380
381# Handle a verbatim paragraph.  Just print it out, but indent it according to
382# our margin.
383sub cmd_verbatim {
384    my ($self, $attrs, $text) = @_;
385    $self->item if defined $$self{ITEM};
386    return if $text =~ /^\s*$/;
387    $text =~ s/^(\n*)([ \t]*\S+)/$1 . (' ' x $$self{MARGIN}) . $2/gme;
388    $text =~ s/\s*$/\n\n/;
389    $self->output ($text);
390    return '';
391}
392
393# Handle literal text (produced by =for and similar constructs).  Just output
394# it with the minimum of changes.
395sub cmd_data {
396    my ($self, $attrs, $text) = @_;
397    $text =~ s/^\n+//;
398    $text =~ s/\n{0,2}$/\n/;
399    $self->output ($text);
400    return '';
401}
402
403##############################################################################
404# Headings
405##############################################################################
406
407# The common code for handling all headers.  Takes the header text, the
408# indentation, and the surrounding marker for the alt formatting method.
409sub heading {
410    my ($self, $text, $indent, $marker) = @_;
411    $self->item ("\n\n") if defined $$self{ITEM};
412    $text =~ s/\s+$//;
413    if ($$self{opt_alt}) {
414        my $closemark = reverse (split (//, $marker));
415        my $margin = ' ' x $$self{opt_margin};
416        $self->output ("\n" . "$margin$marker $text $closemark" . "\n\n");
417    } else {
418        $text .= "\n" if $$self{opt_loose};
419        my $margin = ' ' x ($$self{opt_margin} + $indent);
420        $self->output ($margin . $text . "\n");
421    }
422    return '';
423}
424
425# First level heading.
426sub cmd_head1 {
427    my ($self, $attrs, $text) = @_;
428    $self->heading ($text, 0, '====');
429}
430
431# Second level heading.
432sub cmd_head2 {
433    my ($self, $attrs, $text) = @_;
434    $self->heading ($text, $$self{opt_indent} / 2, '==  ');
435}
436
437# Third level heading.
438sub cmd_head3 {
439    my ($self, $attrs, $text) = @_;
440    $self->heading ($text, $$self{opt_indent} * 2 / 3 + 0.5, '=   ');
441}
442
443# Fourth level heading.
444sub cmd_head4 {
445    my ($self, $attrs, $text) = @_;
446    $self->heading ($text, $$self{opt_indent} * 3 / 4 + 0.5, '-   ');
447}
448
449##############################################################################
450# List handling
451##############################################################################
452
453# Handle the beginning of an =over block.  Takes the type of the block as the
454# first argument, and then the attr hash.  This is called by the handlers for
455# the four different types of lists (bullet, number, text, and block).
456sub over_common_start {
457    my ($self, $attrs) = @_;
458    $self->item ("\n\n") if defined $$self{ITEM};
459
460    # Find the indentation level.
461    my $indent = $$attrs{indent};
462    unless (defined ($indent) && $indent =~ /^\s*[-+]?\d{1,4}\s*$/) {
463        $indent = $$self{opt_indent};
464    }
465
466    # Add this to our stack of indents and increase our current margin.
467    push (@{ $$self{INDENTS} }, $$self{MARGIN});
468    $$self{MARGIN} += ($indent + 0);
469    return '';
470}
471
472# End an =over block.  Takes no options other than the class pointer.  Output
473# any pending items and then pop one level of indentation.
474sub over_common_end {
475    my ($self) = @_;
476    $self->item ("\n\n") if defined $$self{ITEM};
477    $$self{MARGIN} = pop @{ $$self{INDENTS} };
478    return '';
479}
480
481# Dispatch the start and end calls as appropriate.
482sub start_over_bullet { $_[0]->over_common_start ($_[1]) }
483sub start_over_number { $_[0]->over_common_start ($_[1]) }
484sub start_over_text   { $_[0]->over_common_start ($_[1]) }
485sub start_over_block  { $_[0]->over_common_start ($_[1]) }
486sub end_over_bullet { $_[0]->over_common_end }
487sub end_over_number { $_[0]->over_common_end }
488sub end_over_text   { $_[0]->over_common_end }
489sub end_over_block  { $_[0]->over_common_end }
490
491# The common handler for all item commands.  Takes the type of the item, the
492# attributes, and then the text of the item.
493sub item_common {
494    my ($self, $type, $attrs, $text) = @_;
495    $self->item if defined $$self{ITEM};
496
497    # Clean up the text.  We want to end up with two variables, one ($text)
498    # which contains any body text after taking out the item portion, and
499    # another ($item) which contains the actual item text.  Note the use of
500    # the internal Pod::Simple attribute here; that's a potential land mine.
501    $text =~ s/\s+$//;
502    my ($item, $index);
503    if ($type eq 'bullet') {
504        $item = '*';
505    } elsif ($type eq 'number') {
506        $item = $$attrs{'~orig_content'};
507    } else {
508        $item = $text;
509        $item =~ s/\s*\n\s*/ /g;
510        $text = '';
511    }
512    $$self{ITEM} = $item;
513
514    # If body text for this item was included, go ahead and output that now.
515    if ($text) {
516        $text =~ s/\s*$/\n/;
517        $self->item ($text);
518    }
519    return '';
520}
521
522# Dispatch the item commands to the appropriate place.
523sub cmd_item_bullet { my $self = shift; $self->item_common ('bullet', @_) }
524sub cmd_item_number { my $self = shift; $self->item_common ('number', @_) }
525sub cmd_item_text   { my $self = shift; $self->item_common ('text',   @_) }
526sub cmd_item_block  { my $self = shift; $self->item_common ('block',  @_) }
527
528##############################################################################
529# Formatting codes
530##############################################################################
531
532# The simple ones.
533sub cmd_b { return $_[0]{alt} ? "``$_[2]''" : $_[2] }
534sub cmd_f { return $_[0]{alt} ? "\"$_[2]\"" : $_[2] }
535sub cmd_i { return '*' . $_[2] . '*' }
536sub cmd_x { return '' }
537
538# Apply a whole bunch of messy heuristics to not quote things that don't
539# benefit from being quoted.  These originally come from Barrie Slaymaker and
540# largely duplicate code in Pod::Man.
541sub cmd_c {
542    my ($self, $attrs, $text) = @_;
543
544    # A regex that matches the portion of a variable reference that's the
545    # array or hash index, separated out just because we want to use it in
546    # several places in the following regex.
547    my $index = '(?: \[.*\] | \{.*\} )?';
548
549    # Check for things that we don't want to quote, and if we find any of
550    # them, return the string with just a font change and no quoting.
551    $text =~ m{
552      ^\s*
553      (?:
554         ( [\'\`\"] ) .* \1                             # already quoted
555       | \` .* \'                                       # `quoted'
556       | \$+ [\#^]? \S $index                           # special ($^Foo, $")
557       | [\$\@%&*]+ \#? [:\'\w]+ $index                 # plain var or func
558       | [\$\@%&*]* [:\'\w]+ (?: -> )? \(\s*[^\s,]\s*\) # 0/1-arg func call
559       | [+-]? ( \d[\d.]* | \.\d+ ) (?: [eE][+-]?\d+ )? # a number
560       | 0x [a-fA-F\d]+                                 # a hex constant
561      )
562      \s*\z
563     }xo && return $text;
564
565    # If we didn't return, go ahead and quote the text.
566    return $$self{opt_alt}
567        ? "``$text''"
568        : "$$self{LQUOTE}$text$$self{RQUOTE}";
569}
570
571# Links reduce to the text that we're given, wrapped in angle brackets if it's
572# a URL.
573sub cmd_l {
574    my ($self, $attrs, $text) = @_;
575    if ($$attrs{type} eq 'url') {
576        if (not defined($$attrs{to}) or $$attrs{to} eq $text) {
577            return "<$text>";
578        } else {
579            return "$text <$$attrs{to}>";
580        }
581    } else {
582        return $text;
583    }
584}
585
586##############################################################################
587# Backwards compatibility
588##############################################################################
589
590# The old Pod::Text module did everything in a pod2text() function.  This
591# tries to provide the same interface for legacy applications.
592sub pod2text {
593    my @args;
594
595    # This is really ugly; I hate doing option parsing in the middle of a
596    # module.  But the old Pod::Text module supported passing flags to its
597    # entry function, so handle -a and -<number>.
598    while ($_[0] =~ /^-/) {
599        my $flag = shift;
600        if    ($flag eq '-a')       { push (@args, alt => 1)    }
601        elsif ($flag =~ /^-(\d+)$/) { push (@args, width => $1) }
602        else {
603            unshift (@_, $flag);
604            last;
605        }
606    }
607
608    # Now that we know what arguments we're using, create the parser.
609    my $parser = Pod::Text->new (@args);
610
611    # If two arguments were given, the second argument is going to be a file
612    # handle.  That means we want to call parse_from_filehandle(), which means
613    # we need to turn the first argument into a file handle.  Magic open will
614    # handle the <&STDIN case automagically.
615    if (defined $_[1]) {
616        my @fhs = @_;
617        local *IN;
618        unless (open (IN, $fhs[0])) {
619            croak ("Can't open $fhs[0] for reading: $!\n");
620            return;
621        }
622        $fhs[0] = \*IN;
623        $parser->output_fh ($fhs[1]);
624        my $retval = $parser->parse_file ($fhs[0]);
625        my $fh = $parser->output_fh ();
626        close $fh;
627        return $retval;
628    } else {
629        $parser->output_fh (\*STDOUT);
630        return $parser->parse_file (@_);
631    }
632}
633
634# Reset the underlying Pod::Simple object between calls to parse_from_file so
635# that the same object can be reused to convert multiple pages.
636sub parse_from_file {
637    my $self = shift;
638    $self->reinit;
639
640    # Fake the old cutting option to Pod::Parser.  This fiddings with internal
641    # Pod::Simple state and is quite ugly; we need a better approach.
642    if (ref ($_[0]) eq 'HASH') {
643        my $opts = shift @_;
644        if (defined ($$opts{-cutting}) && !$$opts{-cutting}) {
645            $$self{in_pod} = 1;
646            $$self{last_was_blank} = 1;
647        }
648    }
649
650    # Do the work.
651    my $retval = $self->Pod::Simple::parse_from_file (@_);
652
653    # Flush output, since Pod::Simple doesn't do this.  Ideally we should also
654    # close the file descriptor if we had to open one, but we can't easily
655    # figure this out.
656    my $fh = $self->output_fh ();
657    my $oldfh = select $fh;
658    my $oldflush = $|;
659    $| = 1;
660    print $fh '';
661    $| = $oldflush;
662    select $oldfh;
663    return $retval;
664}
665
666# Pod::Simple failed to provide this backward compatibility function, so
667# implement it ourselves.  File handles are one of the inputs that
668# parse_from_file supports.
669sub parse_from_filehandle {
670    my $self = shift;
671    $self->parse_from_file (@_);
672}
673
674sub begin_pod {
675    my $self = shift;
676    $$self{EXCLUDE} = 0;
677    $$self{VERBATIM} = 0;
678}
679
680##############################################################################
681# Module return value and documentation
682##############################################################################
683
6841;
685__END__
686
687=head1 NAME
688
689Pod::Text - Convert POD data to formatted ASCII text
690
691=for stopwords
692alt stderr Allbery Sean Burke's Christiansen UTF-8 pre-Unicode utf8
693
694=head1 SYNOPSIS
695
696    use Pod::Text;
697    my $parser = Pod::Text->new (sentence => 0, width => 78);
698
699    # Read POD from STDIN and write to STDOUT.
700    $parser->parse_from_filehandle;
701
702    # Read POD from file.pod and write to file.txt.
703    $parser->parse_from_file ('file.pod', 'file.txt');
704
705=head1 DESCRIPTION
706
707Pod::Text is a module that can convert documentation in the POD format (the
708preferred language for documenting Perl) into formatted ASCII.  It uses no
709special formatting controls or codes whatsoever, and its output is therefore
710suitable for nearly any device.
711
712As a derived class from Pod::Simple, Pod::Text supports the same methods and
713interfaces.  See L<Pod::Simple> for all the details; briefly, one creates a
714new parser with C<< Pod::Text->new() >> and then normally calls parse_file().
715
716new() can take options, in the form of key/value pairs, that control the
717behavior of the parser.  The currently recognized options are:
718
719=over 4
720
721=item alt
722
723If set to a true value, selects an alternate output format that, among other
724things, uses a different heading style and marks C<=item> entries with a
725colon in the left margin.  Defaults to false.
726
727=item code
728
729If set to a true value, the non-POD parts of the input file will be included
730in the output.  Useful for viewing code documented with POD blocks with the
731POD rendered and the code left intact.
732
733=item indent
734
735The number of spaces to indent regular text, and the default indentation for
736C<=over> blocks.  Defaults to 4.
737
738=item loose
739
740If set to a true value, a blank line is printed after a C<=head1> heading.
741If set to false (the default), no blank line is printed after C<=head1>,
742although one is still printed after C<=head2>.  This is the default because
743it's the expected formatting for manual pages; if you're formatting
744arbitrary text documents, setting this to true may result in more pleasing
745output.
746
747=item margin
748
749The width of the left margin in spaces.  Defaults to 0.  This is the margin
750for all text, including headings, not the amount by which regular text is
751indented; for the latter, see the I<indent> option.  To set the right
752margin, see the I<width> option.
753
754=item quotes
755
756Sets the quote marks used to surround CE<lt>> text.  If the value is a
757single character, it is used as both the left and right quote; if it is two
758characters, the first character is used as the left quote and the second as
759the right quoted; and if it is four characters, the first two are used as
760the left quote and the second two as the right quote.
761
762This may also be set to the special value C<none>, in which case no quote
763marks are added around CE<lt>> text.
764
765=item sentence
766
767If set to a true value, Pod::Text will assume that each sentence ends in two
768spaces, and will try to preserve that spacing.  If set to false, all
769consecutive whitespace in non-verbatim paragraphs is compressed into a
770single space.  Defaults to true.
771
772=item stderr
773
774Send error messages about invalid POD to standard error instead of
775appending a POD ERRORS section to the generated output.
776
777=item utf8
778
779By default, Pod::Text uses the same output encoding as the input encoding
780of the POD source (provided that Perl was built with PerlIO; otherwise, it
781doesn't encode its output).  If this option is given, the output encoding
782is forced to UTF-8.
783
784Be aware that, when using this option, the input encoding of your POD
785source must be properly declared unless it is US-ASCII or Latin-1.  POD
786input without an C<=encoding> command will be assumed to be in Latin-1,
787and if it's actually in UTF-8, the output will be double-encoded.  See
788L<perlpod(1)> for more information on the C<=encoding> command.
789
790=item width
791
792The column at which to wrap text on the right-hand side.  Defaults to 76.
793
794=back
795
796The standard Pod::Simple method parse_file() takes one argument, the file or
797file handle to read from, and writes output to standard output unless that
798has been changed with the output_fh() method.  See L<Pod::Simple> for the
799specific details and for other alternative interfaces.
800
801=head1 DIAGNOSTICS
802
803=over 4
804
805=item Bizarre space in item
806
807=item Item called without tag
808
809(W) Something has gone wrong in internal C<=item> processing.  These
810messages indicate a bug in Pod::Text; you should never see them.
811
812=item Can't open %s for reading: %s
813
814(F) Pod::Text was invoked via the compatibility mode pod2text() interface
815and the input file it was given could not be opened.
816
817=item Invalid quote specification "%s"
818
819(F) The quote specification given (the quotes option to the constructor) was
820invalid.  A quote specification must be one, two, or four characters long.
821
822=back
823
824=head1 BUGS
825
826Encoding handling assumes that PerlIO is available and does not work
827properly if it isn't.  The C<utf8> option is therefore not supported
828unless Perl is built with PerlIO support.
829
830=head1 CAVEATS
831
832If Pod::Text is given the C<utf8> option, the encoding of its output file
833handle will be forced to UTF-8 if possible, overriding any existing
834encoding.  This will be done even if the file handle is not created by
835Pod::Text and was passed in from outside.  This maintains consistency
836regardless of PERL_UNICODE and other settings.
837
838If the C<utf8> option is not given, the encoding of its output file handle
839will be forced to the detected encoding of the input POD, which preserves
840whatever the input text is.  This ensures backward compatibility with
841earlier, pre-Unicode versions of this module, without large numbers of
842Perl warnings.
843
844This is not ideal, but it seems to be the best compromise.  If it doesn't
845work for you, please let me know the details of how it broke.
846
847=head1 NOTES
848
849This is a replacement for an earlier Pod::Text module written by Tom
850Christiansen.  It has a revamped interface, since it now uses Pod::Simple,
851but an interface roughly compatible with the old Pod::Text::pod2text()
852function is still available.  Please change to the new calling convention,
853though.
854
855The original Pod::Text contained code to do formatting via termcap
856sequences, although it wasn't turned on by default and it was problematic to
857get it to work at all.  This rewrite doesn't even try to do that, but a
858subclass of it does.  Look for L<Pod::Text::Termcap>.
859
860=head1 SEE ALSO
861
862L<Pod::Simple>, L<Pod::Text::Termcap>, L<perlpod(1)>, L<pod2text(1)>
863
864The current version of this module is always available from its web site at
865L<http://www.eyrie.org/~eagle/software/podlators/>.  It is also part of the
866Perl core distribution as of 5.6.0.
867
868=head1 AUTHOR
869
870Russ Allbery <rra@stanford.edu>, based I<very> heavily on the original
871Pod::Text by Tom Christiansen <tchrist@mox.perl.com> and its conversion to
872Pod::Parser by Brad Appleton <bradapp@enteract.com>.  Sean Burke's initial
873conversion of Pod::Man to use Pod::Simple provided much-needed guidance on
874how to use Pod::Simple.
875
876=head1 COPYRIGHT AND LICENSE
877
878Copyright 1999, 2000, 2001, 2002, 2004, 2006, 2008, 2009 Russ Allbery
879<rra@stanford.edu>.
880
881This program is free software; you may redistribute it and/or modify it
882under the same terms as Perl itself.
883
884=cut
885