1 # Pod::Text -- Convert POD data to formatted ASCII text.
2 # $Id: Text.pm,v 3.8 2006-09-16 20:55:41 eagle Exp $
4 # Copyright 1999, 2000, 2001, 2002, 2004, 2006
5 # by Russ Allbery <rra@stanford.edu>
7 # This program is free software; you may redistribute it and/or modify it
8 # under the same terms as Perl itself.
10 # This module converts POD to formatted text. It replaces the old Pod::Text
11 # module that came with versions of Perl prior to 5.6.0 and attempts to match
12 # its output except for some specific circumstances where other decisions
13 # seemed to produce better output. It uses Pod::Parser and is designed to be
14 # very easy to subclass.
16 # Perl core hackers, please note that this module is also separately
17 # maintained outside of the Perl core as part of the podlators. Please send
18 # me any patches at the address above in addition to sending them to the
19 # standard Perl mailing lists.
21 ##############################################################################
22 # Modules and declarations
23 ##############################################################################
30 use vars qw(@ISA @EXPORT %ESCAPES $VERSION);
32 use Carp qw(carp croak);
36 @ISA = qw(Pod::Simple Exporter);
38 # We have to export pod2text for backward compatibility.
39 @EXPORT = qw(pod2text);
41 # Don't use the CVS revision as the version, since this module is also in Perl
42 # core and too many things could munge CVS magic revision strings. This
43 # number should ideally be the same as the CVS revision in podlators, however.
46 ##############################################################################
48 ##############################################################################
50 # This function handles code blocks. It's registered as a callback to
51 # Pod::Simple and therefore doesn't work as a regular method call, but all it
52 # does is call output_code with the line.
54 my ($line, $number, $parser) = @_;
55 $parser->output_code ($line . "\n");
58 # Initialize the object and set various Pod::Simple options that we need.
59 # Here, we also process any additional options passed to the constructor or
60 # set up defaults if none were given. Note that all internal object keys are
61 # in all-caps, reserving all lower-case object keys for Pod::Simple and user
65 my $self = $class->SUPER::new;
67 # Tell Pod::Simple to handle S<> by automatically inserting .
68 $self->nbsp_for_S (1);
70 # Tell Pod::Simple to keep whitespace whenever possible.
71 if ($self->can ('preserve_whitespace')) {
72 $self->preserve_whitespace (1);
74 $self->fullstop_space_harden (1);
77 # The =for and =begin targets that we accept.
78 $self->accept_targets (qw/text TEXT/);
80 # Ensure that contiguous blocks of code are merged together. Otherwise,
81 # some of the guesswork heuristics don't work right.
82 $self->merge_text (1);
84 # Pod::Simple doesn't do anything useful with our arguments, but we want
85 # to put them in our object as hash keys and values. This could cause
86 # problems if we ever clash with Pod::Simple's own internal class
89 my @opts = map { ("opt_$_", $opts{$_}) } keys %opts;
90 %$self = (%$self, @opts);
92 # Initialize various things from our parameters.
93 $$self{opt_alt} = 0 unless defined $$self{opt_alt};
94 $$self{opt_indent} = 4 unless defined $$self{opt_indent};
95 $$self{opt_margin} = 0 unless defined $$self{opt_margin};
96 $$self{opt_loose} = 0 unless defined $$self{opt_loose};
97 $$self{opt_sentence} = 0 unless defined $$self{opt_sentence};
98 $$self{opt_width} = 76 unless defined $$self{opt_width};
100 # Figure out what quotes we'll be using for C<> text.
101 $$self{opt_quotes} ||= '"';
102 if ($$self{opt_quotes} eq 'none') {
103 $$self{LQUOTE} = $$self{RQUOTE} = '';
104 } elsif (length ($$self{opt_quotes}) == 1) {
105 $$self{LQUOTE} = $$self{RQUOTE} = $$self{opt_quotes};
106 } elsif ($$self{opt_quotes} =~ /^(.)(.)$/
107 || $$self{opt_quotes} =~ /^(..)(..)$/) {
111 croak qq(Invalid quote specification "$$self{opt_quotes}");
114 # If requested, do something with the non-POD text.
115 $self->code_handler (\&handle_code) if $$self{opt_code};
117 # Return the created object.
121 ##############################################################################
123 ##############################################################################
125 # This is the glue that connects the code below with Pod::Simple itself. The
126 # goal is to convert the event stream coming from the POD parser into method
127 # calls to handlers once the complete content of a tag has been seen. Each
128 # paragraph or POD command will have textual content associated with it, and
129 # as soon as all of a paragraph or POD command has been seen, that content
130 # will be passed in to the corresponding method for handling that type of
131 # object. The exceptions are handlers for lists, which have opening tag
132 # handlers and closing tag handlers that will be called right away.
134 # The internal hash key PENDING is used to store the contents of a tag until
135 # all of it has been seen. It holds a stack of open tags, each one
136 # represented by a tuple of the attributes hash for the tag and the contents
139 # Add a block of text to the contents of the current node, formatting it
140 # according to the current formatting instructions as we do.
142 my ($self, $text) = @_;
143 my $tag = $$self{PENDING}[-1];
147 # Given an element name, get the corresponding method name.
148 sub method_for_element {
149 my ($self, $element) = @_;
151 $element =~ tr/A-Z/a-z/;
152 $element =~ tr/_a-z0-9//cd;
156 # Handle the start of a new element. If cmd_element is defined, assume that
157 # we need to collect the entire tree for this element before passing it to the
158 # element method, and create a new tree into which we'll collect blocks of
159 # text and nested elements. Otherwise, if start_element is defined, call it.
160 sub _handle_element_start {
161 my ($self, $element, $attrs) = @_;
162 my $method = $self->method_for_element ($element);
164 # If we have a command handler, we need to accumulate the contents of the
165 # tag before calling it.
166 if ($self->can ("cmd_$method")) {
167 push (@{ $$self{PENDING} }, [ $attrs, '' ]);
168 } elsif ($self->can ("start_$method")) {
169 my $method = 'start_' . $method;
170 $self->$method ($attrs, '');
174 # Handle the end of an element. If we had a cmd_ method for this element,
175 # this is where we pass along the text that we've accumulated. Otherwise, if
176 # we have an end_ method for the element, call that.
177 sub _handle_element_end {
178 my ($self, $element) = @_;
179 my $method = $self->method_for_element ($element);
181 # If we have a command handler, pull off the pending text and pass it to
182 # the handler along with the saved attribute hash.
183 if ($self->can ("cmd_$method")) {
184 my $tag = pop @{ $$self{PENDING} };
185 my $method = 'cmd_' . $method;
186 my $text = $self->$method (@$tag);
188 if (@{ $$self{PENDING} } > 1) {
189 $$self{PENDING}[-1][1] .= $text;
191 $self->output ($text);
194 } elsif ($self->can ("end_$method")) {
195 my $method = 'end_' . $method;
200 ##############################################################################
202 ##############################################################################
204 # Wrap a line, indenting by the current left margin. We can't use Text::Wrap
205 # because it plays games with tabs. We can't use formline, even though we'd
206 # really like to, because it screws up non-printing characters. So we have to
207 # do the wrapping ourselves.
212 my $spaces = ' ' x $$self{MARGIN};
213 my $width = $$self{opt_width} - $$self{MARGIN};
214 while (length > $width) {
215 if (s/^([^\n]{0,$width})\s+// || s/^([^\n]{$width})//) {
216 $output .= $spaces . $1 . "\n";
221 $output .= $spaces . $_;
222 $output =~ s/\s+$/\n\n/;
226 # Reformat a paragraph of text for the current margin. Takes the text to
227 # reformat and returns the formatted text.
232 # If we're trying to preserve two spaces after sentences, do some munging
233 # to support that. Otherwise, smash all repeated whitespace.
234 if ($$self{opt_sentence}) {
242 return $self->wrap ($_);
245 # Output text to the output device.
247 my ($self, $text) = @_;
248 $text =~ tr/\240\255/ /d;
249 print { $$self{output_fh} } $text;
252 # Output a block of code (something that isn't part of the POD text). Called
253 # by preprocess_paragraph only if we were given the code option. Exists here
254 # only so that it can be overridden by subclasses.
255 sub output_code { $_[0]->output ($_[1]) }
257 ##############################################################################
258 # Document initialization
259 ##############################################################################
261 # Set up various things that have to be initialized on a per-document basis.
264 my $margin = $$self{opt_indent} + $$self{opt_margin};
266 # Initialize a few per-document variables.
267 $$self{INDENTS} = []; # Stack of indentations.
268 $$self{MARGIN} = $margin; # Default left margin.
269 $$self{PENDING} = [[]]; # Pending output.
274 ##############################################################################
276 ##############################################################################
278 # This method is called whenever an =item command is complete (in other words,
279 # we've seen its associated paragraph or know for certain that it doesn't have
280 # one). It gets the paragraph associated with the item as an argument. If
281 # that argument is empty, just output the item tag; if it contains a newline,
282 # output the item tag followed by the newline. Otherwise, see if there's
283 # enough room for us to output the item tag in the margin of the text or if we
284 # have to put it on a separate line.
286 my ($self, $text) = @_;
287 my $tag = $$self{ITEM};
288 unless (defined $tag) {
289 carp "Item called without tag";
294 # Calculate the indentation and margin. $fits is set to true if the tag
295 # will fit into the margin of the paragraph given our indentation level.
296 my $indent = $$self{INDENTS}[-1];
297 $indent = $$self{opt_indent} unless defined $indent;
298 my $margin = ' ' x $$self{opt_margin};
299 my $fits = ($$self{MARGIN} - $indent >= length ($tag) + 1);
301 # If the tag doesn't fit, or if we have no associated text, print out the
302 # tag separately. Otherwise, put the tag in the margin of the paragraph.
303 if (!$text || $text =~ /^\s+$/ || !$fits) {
304 my $realindent = $$self{MARGIN};
305 $$self{MARGIN} = $indent;
306 my $output = $self->reformat ($tag);
307 $output =~ s/^$margin /$margin:/ if ($$self{opt_alt} && $indent > 0);
308 $output =~ s/\n*$/\n/;
310 # If the text is just whitespace, we have an empty item paragraph;
311 # this can result from =over/=item/=back without any intermixed
312 # paragraphs. Insert some whitespace to keep the =item from merging
313 # into the next paragraph.
314 $output .= "\n" if $text && $text =~ /^\s*$/;
316 $self->output ($output);
317 $$self{MARGIN} = $realindent;
318 $self->output ($self->reformat ($text)) if ($text && $text =~ /\S/);
320 my $space = ' ' x $indent;
321 $space =~ s/^$margin /$margin:/ if $$self{opt_alt};
322 $text = $self->reformat ($text);
323 $text =~ s/^$margin /$margin:/ if ($$self{opt_alt} && $indent > 0);
324 my $tagspace = ' ' x length $tag;
325 $text =~ s/^($space)$tagspace/$1$tag/ or warn "Bizarre space in item";
326 $self->output ($text);
330 # Handle a basic block of text. The only tricky thing here is that if there
331 # is a pending item tag, we need to format this as an item paragraph.
333 my ($self, $attrs, $text) = @_;
335 if (defined $$self{ITEM}) {
336 $self->item ($text . "\n");
338 $self->output ($self->reformat ($text . "\n"));
343 # Handle a verbatim paragraph. Just print it out, but indent it according to
346 my ($self, $attrs, $text) = @_;
347 $self->item if defined $$self{ITEM};
348 return if $text =~ /^\s*$/;
349 $text =~ s/^(\n*)(\s*\S+)/$1 . (' ' x $$self{MARGIN}) . $2/gme;
350 $text =~ s/\s*$/\n\n/;
351 $self->output ($text);
355 # Handle literal text (produced by =for and similar constructs). Just output
356 # it with the minimum of changes.
358 my ($self, $attrs, $text) = @_;
360 $text =~ s/\n{0,2}$/\n/;
361 $self->output ($text);
365 ##############################################################################
367 ##############################################################################
369 # The common code for handling all headers. Takes the header text, the
370 # indentation, and the surrounding marker for the alt formatting method.
372 my ($self, $text, $indent, $marker) = @_;
373 $self->item ("\n\n") if defined $$self{ITEM};
375 if ($$self{opt_alt}) {
376 my $closemark = reverse (split (//, $marker));
377 my $margin = ' ' x $$self{opt_margin};
378 $self->output ("\n" . "$margin$marker $text $closemark" . "\n\n");
380 $text .= "\n" if $$self{opt_loose};
381 my $margin = ' ' x ($$self{opt_margin} + $indent);
382 $self->output ($margin . $text . "\n");
387 # First level heading.
389 my ($self, $attrs, $text) = @_;
390 $self->heading ($text, 0, '====');
393 # Second level heading.
395 my ($self, $attrs, $text) = @_;
396 $self->heading ($text, $$self{opt_indent} / 2, '== ');
399 # Third level heading.
401 my ($self, $attrs, $text) = @_;
402 $self->heading ($text, $$self{opt_indent} * 2 / 3 + 0.5, '= ');
405 # Fourth level heading.
407 my ($self, $attrs, $text) = @_;
408 $self->heading ($text, $$self{opt_indent} * 3 / 4 + 0.5, '- ');
411 ##############################################################################
413 ##############################################################################
415 # Handle the beginning of an =over block. Takes the type of the block as the
416 # first argument, and then the attr hash. This is called by the handlers for
417 # the four different types of lists (bullet, number, text, and block).
418 sub over_common_start {
419 my ($self, $attrs) = @_;
420 $self->item ("\n\n") if defined $$self{ITEM};
422 # Find the indentation level.
423 my $indent = $$attrs{indent};
424 unless (defined ($indent) && $indent =~ /^\s*[-+]?\d{1,4}\s*$/) {
425 $indent = $$self{opt_indent};
428 # Add this to our stack of indents and increase our current margin.
429 push (@{ $$self{INDENTS} }, $$self{MARGIN});
430 $$self{MARGIN} += ($indent + 0);
434 # End an =over block. Takes no options other than the class pointer. Output
435 # any pending items and then pop one level of indentation.
436 sub over_common_end {
438 $self->item ("\n\n") if defined $$self{ITEM};
439 $$self{MARGIN} = pop @{ $$self{INDENTS} };
443 # Dispatch the start and end calls as appropriate.
444 sub start_over_bullet { $_[0]->over_common_start ($_[1]) }
445 sub start_over_number { $_[0]->over_common_start ($_[1]) }
446 sub start_over_text { $_[0]->over_common_start ($_[1]) }
447 sub start_over_block { $_[0]->over_common_start ($_[1]) }
448 sub end_over_bullet { $_[0]->over_common_end }
449 sub end_over_number { $_[0]->over_common_end }
450 sub end_over_text { $_[0]->over_common_end }
451 sub end_over_block { $_[0]->over_common_end }
453 # The common handler for all item commands. Takes the type of the item, the
454 # attributes, and then the text of the item.
456 my ($self, $type, $attrs, $text) = @_;
457 $self->item if defined $$self{ITEM};
459 # Clean up the text. We want to end up with two variables, one ($text)
460 # which contains any body text after taking out the item portion, and
461 # another ($item) which contains the actual item text. Note the use of
462 # the internal Pod::Simple attribute here; that's a potential land mine.
465 if ($type eq 'bullet') {
467 } elsif ($type eq 'number') {
468 $item = $$attrs{'~orig_content'};
471 $item =~ s/\s*\n\s*/ /g;
474 $$self{ITEM} = $item;
476 # If body text for this item was included, go ahead and output that now.
484 # Dispatch the item commands to the appropriate place.
485 sub cmd_item_bullet { my $self = shift; $self->item_common ('bullet', @_) }
486 sub cmd_item_number { my $self = shift; $self->item_common ('number', @_) }
487 sub cmd_item_text { my $self = shift; $self->item_common ('text', @_) }
488 sub cmd_item_block { my $self = shift; $self->item_common ('block', @_) }
490 ##############################################################################
492 ##############################################################################
495 sub cmd_b { return $_[0]{alt} ? "``$_[2]''" : $_[2] }
496 sub cmd_f { return $_[0]{alt} ? "\"$_[2]\"" : $_[2] }
497 sub cmd_i { return '*' . $_[2] . '*' }
498 sub cmd_x { return '' }
500 # Apply a whole bunch of messy heuristics to not quote things that don't
501 # benefit from being quoted. These originally come from Barrie Slaymaker and
502 # largely duplicate code in Pod::Man.
504 my ($self, $attrs, $text) = @_;
506 # A regex that matches the portion of a variable reference that's the
507 # array or hash index, separated out just because we want to use it in
508 # several places in the following regex.
509 my $index = '(?: \[.*\] | \{.*\} )?';
511 # Check for things that we don't want to quote, and if we find any of
512 # them, return the string with just a font change and no quoting.
516 ( [\'\`\"] ) .* \1 # already quoted
517 | \` .* \' # `quoted'
518 | \$+ [\#^]? \S $index # special ($^Foo, $")
519 | [\$\@%&*]+ \#? [:\'\w]+ $index # plain var or func
520 | [\$\@%&*]* [:\'\w]+ (?: -> )? \(\s*[^\s,]\s*\) # 0/1-arg func call
521 | [+-]? ( \d[\d.]* | \.\d+ ) (?: [eE][+-]?\d+ )? # a number
522 | 0x [a-fA-F\d]+ # a hex constant
527 # If we didn't return, go ahead and quote the text.
528 return $$self{opt_alt}
530 : "$$self{LQUOTE}$text$$self{RQUOTE}";
533 # Links reduce to the text that we're given, wrapped in angle brackets if it's
536 my ($self, $attrs, $text) = @_;
537 return $$attrs{type} eq 'url' ? "<$text>" : $text;
540 ##############################################################################
541 # Backwards compatibility
542 ##############################################################################
544 # The old Pod::Text module did everything in a pod2text() function. This
545 # tries to provide the same interface for legacy applications.
549 # This is really ugly; I hate doing option parsing in the middle of a
550 # module. But the old Pod::Text module supported passing flags to its
551 # entry function, so handle -a and -<number>.
552 while ($_[0] =~ /^-/) {
554 if ($flag eq '-a') { push (@args, alt => 1) }
555 elsif ($flag =~ /^-(\d+)$/) { push (@args, width => $1) }
562 # Now that we know what arguments we're using, create the parser.
563 my $parser = Pod::Text->new (@args);
565 # If two arguments were given, the second argument is going to be a file
566 # handle. That means we want to call parse_from_filehandle(), which means
567 # we need to turn the first argument into a file handle. Magic open will
568 # handle the <&STDIN case automagically.
572 unless (open (IN, $fhs[0])) {
573 croak ("Can't open $fhs[0] for reading: $!\n");
577 $parser->output_fh ($fhs[1]);
578 my $retval = $parser->parse_file ($fhs[0]);
579 my $fh = $parser->output_fh ();
583 return $parser->parse_file (@_);
587 # Reset the underlying Pod::Simple object between calls to parse_from_file so
588 # that the same object can be reused to convert multiple pages.
589 sub parse_from_file {
593 # Fake the old cutting option to Pod::Parser. This fiddings with internal
594 # Pod::Simple state and is quite ugly; we need a better approach.
595 if (ref ($_[0]) eq 'HASH') {
597 if (defined ($$opts{-cutting}) && !$$opts{-cutting}) {
599 $$self{last_was_blank} = 1;
604 my $retval = $self->Pod::Simple::parse_from_file (@_);
606 # Flush output, since Pod::Simple doesn't do this. Ideally we should also
607 # close the file descriptor if we had to open one, but we can't easily
609 my $fh = $self->output_fh ();
610 my $oldfh = select $fh;
619 # Pod::Simple failed to provide this backward compatibility function, so
620 # implement it ourselves. File handles are one of the inputs that
621 # parse_from_file supports.
622 sub parse_from_filehandle {
624 $self->parse_from_file (@_);
627 ##############################################################################
628 # Module return value and documentation
629 ##############################################################################
636 Pod::Text - Convert POD data to formatted ASCII text
641 my $parser = Pod::Text->new (sentence => 0, width => 78);
643 # Read POD from STDIN and write to STDOUT.
644 $parser->parse_from_filehandle;
646 # Read POD from file.pod and write to file.txt.
647 $parser->parse_from_file ('file.pod', 'file.txt');
651 Pod::Text is a module that can convert documentation in the POD format (the
652 preferred language for documenting Perl) into formatted ASCII. It uses no
653 special formatting controls or codes whatsoever, and its output is therefore
654 suitable for nearly any device.
656 As a derived class from Pod::Simple, Pod::Text supports the same methods and
657 interfaces. See L<Pod::Simple> for all the details; briefly, one creates a
658 new parser with C<< Pod::Text->new() >> and then normally calls parse_file().
660 new() can take options, in the form of key/value pairs, that control the
661 behavior of the parser. The currently recognized options are:
667 If set to a true value, selects an alternate output format that, among other
668 things, uses a different heading style and marks C<=item> entries with a
669 colon in the left margin. Defaults to false.
673 If set to a true value, the non-POD parts of the input file will be included
674 in the output. Useful for viewing code documented with POD blocks with the
675 POD rendered and the code left intact.
679 The number of spaces to indent regular text, and the default indentation for
680 C<=over> blocks. Defaults to 4.
684 If set to a true value, a blank line is printed after a C<=head1> heading.
685 If set to false (the default), no blank line is printed after C<=head1>,
686 although one is still printed after C<=head2>. This is the default because
687 it's the expected formatting for manual pages; if you're formatting
688 arbitrary text documents, setting this to true may result in more pleasing
693 The width of the left margin in spaces. Defaults to 0. This is the margin
694 for all text, including headings, not the amount by which regular text is
695 indented; for the latter, see the I<indent> option. To set the right
696 margin, see the I<width> option.
700 Sets the quote marks used to surround CE<lt>> text. If the value is a
701 single character, it is used as both the left and right quote; if it is two
702 characters, the first character is used as the left quote and the second as
703 the right quoted; and if it is four characters, the first two are used as
704 the left quote and the second two as the right quote.
706 This may also be set to the special value C<none>, in which case no quote
707 marks are added around CE<lt>> text.
711 If set to a true value, Pod::Text will assume that each sentence ends in two
712 spaces, and will try to preserve that spacing. If set to false, all
713 consecutive whitespace in non-verbatim paragraphs is compressed into a
714 single space. Defaults to true.
718 The column at which to wrap text on the right-hand side. Defaults to 76.
722 The standard Pod::Simple method parse_file() takes one argument, the file or
723 file handle to read from, and writes output to standard output unless that
724 has been changed with the output_fh() method. See L<Pod::Simple> for the
725 specific details and for other alternative interfaces.
731 =item Bizarre space in item
733 =item Item called without tag
735 (W) Something has gone wrong in internal C<=item> processing. These
736 messages indicate a bug in Pod::Text; you should never see them.
738 =item Can't open %s for reading: %s
740 (F) Pod::Text was invoked via the compatibility mode pod2text() interface
741 and the input file it was given could not be opened.
743 =item Invalid quote specification "%s"
745 (F) The quote specification given (the quotes option to the constructor) was
746 invalid. A quote specification must be one, two, or four characters long.
752 This is a replacement for an earlier Pod::Text module written by Tom
753 Christiansen. It has a revamped interface, since it now uses Pod::Simple,
754 but an interface roughly compatible with the old Pod::Text::pod2text()
755 function is still available. Please change to the new calling convention,
758 The original Pod::Text contained code to do formatting via termcap
759 sequences, although it wasn't turned on by default and it was problematic to
760 get it to work at all. This rewrite doesn't even try to do that, but a
761 subclass of it does. Look for L<Pod::Text::Termcap>.
765 L<Pod::Simple>, L<Pod::Text::Termcap>, L<pod2text(1)>
767 The current version of this module is always available from its web site at
768 L<http://www.eyrie.org/~eagle/software/podlators/>. It is also part of the
769 Perl core distribution as of 5.6.0.
773 Russ Allbery <rra@stanford.edu>, based I<very> heavily on the original
774 Pod::Text by Tom Christiansen <tchrist@mox.perl.com> and its conversion to
775 Pod::Parser by Brad Appleton <bradapp@enteract.com>. Sean Burke's initial
776 conversion of Pod::Man to use Pod::Simple provided much-needed guidance on
777 how to use Pod::Simple.
779 =head1 COPYRIGHT AND LICENSE
781 Copyright 1999, 2000, 2001, 2002, 2004, 2006 Russ Allbery <rra@stanford.edu>.
783 This program is free software; you may redistribute it and/or modify it
784 under the same terms as Perl itself.