1#############################################################################
2# Pod/Usage.pm -- print usage messages for the running script.
3#
4# Copyright (C) 1996-2000 by Bradford Appleton. All rights reserved.
5# This file is part of "PodParser". PodParser is free software;
6# you can redistribute it and/or modify it under the same terms
7# as Perl itself.
8#############################################################################
9
10package Pod::Usage;
11
12use vars qw($VERSION);
13$VERSION = 1.33;  ## Current version of this package
14require  5.005;    ## requires this Perl version or later
15
16=head1 NAME
17
18Pod::Usage, pod2usage() - print a usage message from embedded pod documentation
19
20=head1 SYNOPSIS
21
22  use Pod::Usage
23
24  my $message_text  = "This text precedes the usage message.";
25  my $exit_status   = 2;          ## The exit status to use
26  my $verbose_level = 0;          ## The verbose level to use
27  my $filehandle    = \*STDERR;   ## The filehandle to write to
28
29  pod2usage($message_text);
30
31  pod2usage($exit_status);
32
33  pod2usage( { -message => $message_text ,
34               -exitval => $exit_status  ,
35               -verbose => $verbose_level,
36               -output  => $filehandle } );
37
38  pod2usage(   -msg     => $message_text ,
39               -exitval => $exit_status  ,
40               -verbose => $verbose_level,
41               -output  => $filehandle   );
42
43  pod2usage(   -verbose => 2,
44               -noperldoc => 1  )
45
46=head1 ARGUMENTS
47
48B<pod2usage> should be given either a single argument, or a list of
49arguments corresponding to an associative array (a "hash"). When a single
50argument is given, it should correspond to exactly one of the following:
51
52=over 4
53
54=item *
55
56A string containing the text of a message to print I<before> printing
57the usage message
58
59=item *
60
61A numeric value corresponding to the desired exit status
62
63=item *
64
65A reference to a hash
66
67=back
68
69If more than one argument is given then the entire argument list is
70assumed to be a hash.  If a hash is supplied (either as a reference or
71as a list) it should contain one or more elements with the following
72keys:
73
74=over 4
75
76=item C<-message>
77
78=item C<-msg>
79
80The text of a message to print immediately prior to printing the
81program's usage message.
82
83=item C<-exitval>
84
85The desired exit status to pass to the B<exit()> function.
86This should be an integer, or else the string "NOEXIT" to
87indicate that control should simply be returned without
88terminating the invoking process.
89
90=item C<-verbose>
91
92The desired level of "verboseness" to use when printing the usage
93message. If the corresponding value is 0, then only the "SYNOPSIS"
94section of the pod documentation is printed. If the corresponding value
95is 1, then the "SYNOPSIS" section, along with any section entitled
96"OPTIONS", "ARGUMENTS", or "OPTIONS AND ARGUMENTS" is printed.  If the
97corresponding value is 2 or more then the entire manpage is printed.
98
99The special verbosity level 99 requires to also specify the -section
100parameter; then these sections are extracted (see L<Pod::Select>)
101and printed.
102
103=item C<-section>
104
105A string representing a selection list for sections to be printed
106when -verbose is set to 99, e.g. C<"NAME|SYNOPSIS|DESCRIPTION|VERSION">.
107
108=item C<-output>
109
110A reference to a filehandle, or the pathname of a file to which the
111usage message should be written. The default is C<\*STDERR> unless the
112exit value is less than 2 (in which case the default is C<\*STDOUT>).
113
114=item C<-input>
115
116A reference to a filehandle, or the pathname of a file from which the
117invoking script's pod documentation should be read.  It defaults to the
118file indicated by C<$0> (C<$PROGRAM_NAME> for users of F<English.pm>).
119
120=item C<-pathlist>
121
122A list of directory paths. If the input file does not exist, then it
123will be searched for in the given directory list (in the order the
124directories appear in the list). It defaults to the list of directories
125implied by C<$ENV{PATH}>. The list may be specified either by a reference
126to an array, or by a string of directory paths which use the same path
127separator as C<$ENV{PATH}> on your system (e.g., C<:> for Unix, C<;> for
128MSWin32 and DOS).
129
130=item C<-noperldoc>
131
132By default, Pod::Usage will call L<perldoc> when -verbose >= 2 is
133specified. This does not work well e.g. if the script was packed
134with L<PAR>. The -noperldoc option suppresses the external call to
135L<perldoc> and uses the simple text formatter (L<Pod::Text>) to
136output the POD.
137
138=back
139
140=head1 DESCRIPTION
141
142B<pod2usage> will print a usage message for the invoking script (using
143its embedded pod documentation) and then exit the script with the
144desired exit status. The usage message printed may have any one of three
145levels of "verboseness": If the verbose level is 0, then only a synopsis
146is printed. If the verbose level is 1, then the synopsis is printed
147along with a description (if present) of the command line options and
148arguments. If the verbose level is 2, then the entire manual page is
149printed.
150
151Unless they are explicitly specified, the default values for the exit
152status, verbose level, and output stream to use are determined as
153follows:
154
155=over 4
156
157=item *
158
159If neither the exit status nor the verbose level is specified, then the
160default is to use an exit status of 2 with a verbose level of 0.
161
162=item *
163
164If an exit status I<is> specified but the verbose level is I<not>, then the
165verbose level will default to 1 if the exit status is less than 2 and
166will default to 0 otherwise.
167
168=item *
169
170If an exit status is I<not> specified but verbose level I<is> given, then
171the exit status will default to 2 if the verbose level is 0 and will
172default to 1 otherwise.
173
174=item *
175
176If the exit status used is less than 2, then output is printed on
177C<STDOUT>.  Otherwise output is printed on C<STDERR>.
178
179=back
180
181Although the above may seem a bit confusing at first, it generally does
182"the right thing" in most situations.  This determination of the default
183values to use is based upon the following typical Unix conventions:
184
185=over 4
186
187=item *
188
189An exit status of 0 implies "success". For example, B<diff(1)> exits
190with a status of 0 if the two files have the same contents.
191
192=item *
193
194An exit status of 1 implies possibly abnormal, but non-defective, program
195termination.  For example, B<grep(1)> exits with a status of 1 if
196it did I<not> find a matching line for the given regular expression.
197
198=item *
199
200An exit status of 2 or more implies a fatal error. For example, B<ls(1)>
201exits with a status of 2 if you specify an illegal (unknown) option on
202the command line.
203
204=item *
205
206Usage messages issued as a result of bad command-line syntax should go
207to C<STDERR>.  However, usage messages issued due to an explicit request
208to print usage (like specifying B<-help> on the command line) should go
209to C<STDOUT>, just in case the user wants to pipe the output to a pager
210(such as B<more(1)>).
211
212=item *
213
214If program usage has been explicitly requested by the user, it is often
215desireable to exit with a status of 1 (as opposed to 0) after issuing
216the user-requested usage message.  It is also desireable to give a
217more verbose description of program usage in this case.
218
219=back
220
221B<pod2usage> doesn't force the above conventions upon you, but it will
222use them by default if you don't expressly tell it to do otherwise.  The
223ability of B<pod2usage()> to accept a single number or a string makes it
224convenient to use as an innocent looking error message handling function:
225
226    use Pod::Usage;
227    use Getopt::Long;
228
229    ## Parse options
230    GetOptions("help", "man", "flag1")  ||  pod2usage(2);
231    pod2usage(1)  if ($opt_help);
232    pod2usage(-verbose => 2)  if ($opt_man);
233
234    ## Check for too many filenames
235    pod2usage("$0: Too many files given.\n")  if (@ARGV > 1);
236
237Some user's however may feel that the above "economy of expression" is
238not particularly readable nor consistent and may instead choose to do
239something more like the following:
240
241    use Pod::Usage;
242    use Getopt::Long;
243
244    ## Parse options
245    GetOptions("help", "man", "flag1")  ||  pod2usage(-verbose => 0);
246    pod2usage(-verbose => 1)  if ($opt_help);
247    pod2usage(-verbose => 2)  if ($opt_man);
248
249    ## Check for too many filenames
250    pod2usage(-verbose => 2, -message => "$0: Too many files given.\n")
251        if (@ARGV > 1);
252
253As with all things in Perl, I<there's more than one way to do it>, and
254B<pod2usage()> adheres to this philosophy.  If you are interested in
255seeing a number of different ways to invoke B<pod2usage> (although by no
256means exhaustive), please refer to L<"EXAMPLES">.
257
258=head1 EXAMPLES
259
260Each of the following invocations of C<pod2usage()> will print just the
261"SYNOPSIS" section to C<STDERR> and will exit with a status of 2:
262
263    pod2usage();
264
265    pod2usage(2);
266
267    pod2usage(-verbose => 0);
268
269    pod2usage(-exitval => 2);
270
271    pod2usage({-exitval => 2, -output => \*STDERR});
272
273    pod2usage({-verbose => 0, -output  => \*STDERR});
274
275    pod2usage(-exitval => 2, -verbose => 0);
276
277    pod2usage(-exitval => 2, -verbose => 0, -output => \*STDERR);
278
279Each of the following invocations of C<pod2usage()> will print a message
280of "Syntax error." (followed by a newline) to C<STDERR>, immediately
281followed by just the "SYNOPSIS" section (also printed to C<STDERR>) and
282will exit with a status of 2:
283
284    pod2usage("Syntax error.");
285
286    pod2usage(-message => "Syntax error.", -verbose => 0);
287
288    pod2usage(-msg  => "Syntax error.", -exitval => 2);
289
290    pod2usage({-msg => "Syntax error.", -exitval => 2, -output => \*STDERR});
291
292    pod2usage({-msg => "Syntax error.", -verbose => 0, -output => \*STDERR});
293
294    pod2usage(-msg  => "Syntax error.", -exitval => 2, -verbose => 0);
295
296    pod2usage(-message => "Syntax error.",
297              -exitval => 2,
298              -verbose => 0,
299              -output  => \*STDERR);
300
301Each of the following invocations of C<pod2usage()> will print the
302"SYNOPSIS" section and any "OPTIONS" and/or "ARGUMENTS" sections to
303C<STDOUT> and will exit with a status of 1:
304
305    pod2usage(1);
306
307    pod2usage(-verbose => 1);
308
309    pod2usage(-exitval => 1);
310
311    pod2usage({-exitval => 1, -output => \*STDOUT});
312
313    pod2usage({-verbose => 1, -output => \*STDOUT});
314
315    pod2usage(-exitval => 1, -verbose => 1);
316
317    pod2usage(-exitval => 1, -verbose => 1, -output => \*STDOUT});
318
319Each of the following invocations of C<pod2usage()> will print the
320entire manual page to C<STDOUT> and will exit with a status of 1:
321
322    pod2usage(-verbose  => 2);
323
324    pod2usage({-verbose => 2, -output => \*STDOUT});
325
326    pod2usage(-exitval  => 1, -verbose => 2);
327
328    pod2usage({-exitval => 1, -verbose => 2, -output => \*STDOUT});
329
330=head2 Recommended Use
331
332Most scripts should print some type of usage message to C<STDERR> when a
333command line syntax error is detected. They should also provide an
334option (usually C<-H> or C<-help>) to print a (possibly more verbose)
335usage message to C<STDOUT>. Some scripts may even wish to go so far as to
336provide a means of printing their complete documentation to C<STDOUT>
337(perhaps by allowing a C<-man> option). The following complete example
338uses B<Pod::Usage> in combination with B<Getopt::Long> to do all of these
339things:
340
341    use Getopt::Long;
342    use Pod::Usage;
343
344    my $man = 0;
345    my $help = 0;
346    ## Parse options and print usage if there is a syntax error,
347    ## or if usage was explicitly requested.
348    GetOptions('help|?' => \$help, man => \$man) or pod2usage(2);
349    pod2usage(1) if $help;
350    pod2usage(-verbose => 2) if $man;
351
352    ## If no arguments were given, then allow STDIN to be used only
353    ## if it's not connected to a terminal (otherwise print usage)
354    pod2usage("$0: No files given.")  if ((@ARGV == 0) && (-t STDIN));
355    __END__
356
357    =head1 NAME
358
359    sample - Using GetOpt::Long and Pod::Usage
360
361    =head1 SYNOPSIS
362
363    sample [options] [file ...]
364
365     Options:
366       -help            brief help message
367       -man             full documentation
368
369    =head1 OPTIONS
370
371    =over 8
372
373    =item B<-help>
374
375    Print a brief help message and exits.
376
377    =item B<-man>
378
379    Prints the manual page and exits.
380
381    =back
382
383    =head1 DESCRIPTION
384
385    B<This program> will read the given input file(s) and do something
386    useful with the contents thereof.
387
388    =cut
389
390=head1 CAVEATS
391
392By default, B<pod2usage()> will use C<$0> as the path to the pod input
393file.  Unfortunately, not all systems on which Perl runs will set C<$0>
394properly (although if C<$0> isn't found, B<pod2usage()> will search
395C<$ENV{PATH}> or else the list specified by the C<-pathlist> option).
396If this is the case for your system, you may need to explicitly specify
397the path to the pod docs for the invoking script using something
398similar to the following:
399
400    pod2usage(-exitval => 2, -input => "/path/to/your/pod/docs");
401
402In the pathological case that a script is called via a relative path
403I<and> the script itself changes the current working directory
404(see L<perlfunc/chdir>) I<before> calling pod2usage, Pod::Usage will
405fail even on robust platforms. Don't do that.
406
407=head1 AUTHOR
408
409Please report bugs using L<http://rt.cpan.org>.
410
411Brad Appleton E<lt>bradapp@enteract.comE<gt>
412
413Based on code for B<Pod::Text::pod2text()> written by
414Tom Christiansen E<lt>tchrist@mox.perl.comE<gt>
415
416=head1 ACKNOWLEDGEMENTS
417
418Steven McDougall E<lt>swmcd@world.std.comE<gt> for his help and patience
419with re-writing this manpage.
420
421=cut
422
423#############################################################################
424
425use strict;
426#use diagnostics;
427use Carp;
428use Config;
429use Exporter;
430use File::Spec;
431
432use vars qw(@ISA @EXPORT);
433@EXPORT = qw(&pod2usage);
434BEGIN {
435    if ( $] >= 5.005_58 ) {
436       require Pod::Text;
437       @ISA = qw( Pod::Text );
438    }
439    else {
440       require Pod::PlainText;
441       @ISA = qw( Pod::PlainText );
442    }
443}
444
445
446##---------------------------------------------------------------------------
447
448##---------------------------------
449## Function definitions begin here
450##---------------------------------
451
452sub pod2usage {
453    local($_) = shift;
454    my %opts;
455    ## Collect arguments
456    if (@_ > 0) {
457        ## Too many arguments - assume that this is a hash and
458        ## the user forgot to pass a reference to it.
459        %opts = ($_, @_);
460    }
461    elsif (!defined $_) {
462      $_ = "";
463    }
464    elsif (ref $_) {
465        ## User passed a ref to a hash
466        %opts = %{$_}  if (ref($_) eq 'HASH');
467    }
468    elsif (/^[-+]?\d+$/) {
469        ## User passed in the exit value to use
470        $opts{"-exitval"} =  $_;
471    }
472    else {
473        ## User passed in a message to print before issuing usage.
474        $_  and  $opts{"-message"} = $_;
475    }
476
477    ## Need this for backward compatibility since we formerly used
478    ## options that were all uppercase words rather than ones that
479    ## looked like Unix command-line options.
480    ## to be uppercase keywords)
481    %opts = map {
482        my $val = $opts{$_};
483        s/^(?=\w)/-/;
484        /^-msg/i   and  $_ = '-message';
485        /^-exit/i  and  $_ = '-exitval';
486        lc($_) => $val;
487    } (keys %opts);
488
489    ## Now determine default -exitval and -verbose values to use
490    if ((! defined $opts{"-exitval"}) && (! defined $opts{"-verbose"})) {
491        $opts{"-exitval"} = 2;
492        $opts{"-verbose"} = 0;
493    }
494    elsif (! defined $opts{"-exitval"}) {
495        $opts{"-exitval"} = ($opts{"-verbose"} > 0) ? 1 : 2;
496    }
497    elsif (! defined $opts{"-verbose"}) {
498        $opts{"-verbose"} = (lc($opts{"-exitval"}) eq "noexit" ||
499                             $opts{"-exitval"} < 2);
500    }
501
502    ## Default the output file
503    $opts{"-output"} = (lc($opts{"-exitval"}) eq "noexit" ||
504                        $opts{"-exitval"} < 2) ? \*STDOUT : \*STDERR
505            unless (defined $opts{"-output"});
506    ## Default the input file
507    $opts{"-input"} = $0  unless (defined $opts{"-input"});
508
509    ## Look up input file in path if it doesnt exist.
510    unless ((ref $opts{"-input"}) || (-e $opts{"-input"})) {
511        my ($dirname, $basename) = ('', $opts{"-input"});
512        my $pathsep = ($^O =~ /^(?:dos|os2|MSWin32)$/) ? ";"
513                            : (($^O eq 'MacOS' || $^O eq 'VMS') ? ',' :  ":");
514        my $pathspec = $opts{"-pathlist"} || $ENV{PATH} || $ENV{PERL5LIB};
515
516        my @paths = (ref $pathspec) ? @$pathspec : split($pathsep, $pathspec);
517        for $dirname (@paths) {
518            $_ = File::Spec->catfile($dirname, $basename)  if length;
519            last if (-e $_) && ($opts{"-input"} = $_);
520        }
521    }
522
523    ## Now create a pod reader and constrain it to the desired sections.
524    my $parser = new Pod::Usage(USAGE_OPTIONS => \%opts);
525    if ($opts{"-verbose"} == 0) {
526        $parser->select('SYNOPSIS\s*');
527    }
528    elsif ($opts{"-verbose"} == 1) {
529        my $opt_re = '(?i)' .
530                     '(?:OPTIONS|ARGUMENTS)' .
531                     '(?:\s*(?:AND|\/)\s*(?:OPTIONS|ARGUMENTS))?';
532        $parser->select( 'SYNOPSIS', $opt_re, "DESCRIPTION/$opt_re" );
533    }
534    elsif ($opts{"-verbose"} == 99) {
535        $parser->select( $opts{"-sections"} );
536        $opts{"-verbose"} = 1;
537    }
538
539    ## Now translate the pod document and then exit with the desired status
540    if ( !$opts{"-noperldoc"}
541             and  $opts{"-verbose"} >= 2
542             and  !ref($opts{"-input"})
543             and  $opts{"-output"} == \*STDOUT )
544    {
545       ## spit out the entire PODs. Might as well invoke perldoc
546       my $progpath = File::Spec->catfile($Config{scriptdir}, "perldoc");
547       system($progpath, $opts{"-input"});
548    }
549    else {
550       $parser->parse_from_file($opts{"-input"}, $opts{"-output"});
551    }
552
553    exit($opts{"-exitval"})  unless (lc($opts{"-exitval"}) eq 'noexit');
554}
555
556##---------------------------------------------------------------------------
557
558##-------------------------------
559## Method definitions begin here
560##-------------------------------
561
562sub new {
563    my $this = shift;
564    my $class = ref($this) || $this;
565    my %params = @_;
566    my $self = {%params};
567    bless $self, $class;
568    if ($self->can('initialize')) {
569        $self->initialize();
570    } else {
571        $self = $self->SUPER::new();
572        %$self = (%$self, %params);
573    }
574    return $self;
575}
576
577sub select {
578    my ($self, @res) = @_;
579    if ($ISA[0]->can('select')) {
580        $self->SUPER::select(@_);
581    } else {
582        $self->{USAGE_SELECT} = \@res;
583    }
584}
585
586# Override Pod::Text->seq_i to return just "arg", not "*arg*".
587sub seq_i { return $_[1] }
588
589# This overrides the Pod::Text method to do something very akin to what
590# Pod::Select did as well as the work done below by preprocess_paragraph.
591# Note that the below is very, very specific to Pod::Text.
592sub _handle_element_end {
593    my ($self, $element) = @_;
594    if ($element eq 'head1') {
595        $$self{USAGE_HEAD1} = $$self{PENDING}[-1][1];
596        $$self{PENDING}[-1][1] =~ s/^\s*SYNOPSIS\s*$/USAGE/;
597    } elsif ($element eq 'head2') {
598        $$self{USAGE_HEAD2} = $$self{PENDING}[-1][1];
599    }
600    if ($element eq 'head1' || $element eq 'head2') {
601        $$self{USAGE_SKIPPING} = 1;
602        my $heading = $$self{USAGE_HEAD1};
603        $heading .= '/' . $$self{USAGE_HEAD2} if defined $$self{USAGE_HEAD2};
604        for (@{ $$self{USAGE_SELECT} }) {
605            if ($heading =~ /^$_\s*$/) {
606                $$self{USAGE_SKIPPING} = 0;
607                last;
608            }
609        }
610
611        # Try to do some lowercasing instead of all-caps in headings, and use
612        # a colon to end all headings.
613        local $_ = $$self{PENDING}[-1][1];
614        s{([A-Z])([A-Z]+)}{((length($2) > 2) ? $1 : lc($1)) . lc($2)}ge;
615        s/\s*$/:/  unless (/:\s*$/);
616        $_ .= "\n";
617        $$self{PENDING}[-1][1] = $_;
618    }
619    if ($$self{USAGE_SKIPPING}) {
620        pop @{ $$self{PENDING} };
621    } else {
622        $self->SUPER::_handle_element_end($element);
623    }
624}
625
626sub start_document {
627    my $self = shift;
628    $self->SUPER::start_document();
629    my $msg = $self->{USAGE_OPTIONS}->{-message}  or  return 1;
630    my $out_fh = $self->output_fh();
631    print $out_fh "$msg\n";
632}
633
634sub begin_pod {
635    my $self = shift;
636    $self->SUPER::begin_pod();  ## Have to call superclass
637    my $msg = $self->{USAGE_OPTIONS}->{-message}  or  return 1;
638    my $out_fh = $self->output_handle();
639    print $out_fh "$msg\n";
640}
641
642sub preprocess_paragraph {
643    my $self = shift;
644    local $_ = shift;
645    my $line = shift;
646    ## See if this is a heading and we arent printing the entire manpage.
647    if (($self->{USAGE_OPTIONS}->{-verbose} < 2) && /^=head/) {
648        ## Change the title of the SYNOPSIS section to USAGE
649        s/^=head1\s+SYNOPSIS\s*$/=head1 USAGE/;
650        ## Try to do some lowercasing instead of all-caps in headings
651        s{([A-Z])([A-Z]+)}{((length($2) > 2) ? $1 : lc($1)) . lc($2)}ge;
652        ## Use a colon to end all headings
653        s/\s*$/:/  unless (/:\s*$/);
654        $_ .= "\n";
655    }
656    return  $self->SUPER::preprocess_paragraph($_);
657}
658
6591; # keep require happy
660