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1#############################################################################
2# Pod/Usage.pm -- print usage messages for the running script.
3#
4# Based on Tom Christiansen's Pod::Text::pod2text() function
5# (with modifications).
6#
7# Copyright (C) 1994-1999 Tom Christiansen. All rights reserved.
8# This file is part of "PodParser". PodParser is free software;
9# you can redistribute it and/or modify it under the same terms
10# as Perl itself.
11#############################################################################
12
13package Pod::Usage;
14
15use vars qw($VERSION);
e9fdc7d2 16$VERSION = 1.081; ## Current version of this package
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17require 5.004; ## requires this Perl version or later
18
19=head1 NAME
20
21Pod::Usage, pod2usage() - print a usage message from embedded pod documentation
22
23=head1 SYNOPSIS
24
25 use Pod::Usage
26
27 my $message_text = "This text precedes the usage message.";
28 my $exit_status = 2; ## The exit status to use
29 my $verbose_level = 0; ## The verbose level to use
30 my $filehandle = \*STDERR; ## The filehandle to write to
31
32 pod2usage($message_text);
33
34 pod2usage($exit_status);
35
36 pod2usage( { -message => $message_text ,
37 -exitval => $exit_status ,
38 -verbose => $verbose_level,
39 -output => $filehandle } );
40
41 pod2usage( -msg => $message_text ,
42 -exitval => $exit_status ,
43 -verbose => $verbose_level,
44 -output => $filehandle );
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
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
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.
86
87=item C<-verbose>
88
89The desired level of "verboseness" to use when printing the usage
90message. If the corresponding value is 0, then only the "SYNOPSIS"
91section of the pod documentation is printed. If the corresponding value
92is 1, then the "SYNOPSIS" section, along with any section entitled
93"OPTIONS", "ARGUMENTS", or "OPTIONS AND ARGUMENTS" is printed. If the
94corresponding value is 2 or more then the entire manpage is printed.
95
96=item C<-output>
97
98A reference to a filehandle, or the pathname of a file to which the
99usage message should be written. The default is C<\*STDERR> unless the
100exit value is less than 2 (in which case the default is C<\*STDOUT>).
101
102=item C<-input>
103
104A reference to a filehandle, or the pathname of a file from which the
105invoking script's pod documentation should be read. It defaults to the
106file indicated by C<$0> (C<$PROGRAM_NAME> for users of F<English.pm>).
107
108=item C<-pathlist>
109
110A list of directory paths. If the input file does not exist, then it
111will be searched for in the given directory list (in the order the
112directories appear in the list). It defaults to the list of directories
113implied by C<$ENV{PATH}>. The list may be specified either by a reference
114to an array, or by a string of directory paths which use the same path
115separator as C<$ENV{PATH}> on your system (e.g., C<:> for Unix, C<;> for
116MSWin32 and DOS).
117
118=back
119
120=head1 DESCRIPTION
121
122B<pod2usage> will print a usage message for the invoking script (using
123its embedded pod documentation) and then exit the script with the
124desired exit status. The usage message printed may have any one of three
125levels of "verboseness": If the verbose level is 0, then only a synopsis
126is printed. If the verbose level is 1, then the synopsis is printed
127along with a description (if present) of the command line options and
128arguments. If the verbose level is 2, then the entire manual page is
129printed.
130
131Unless they are explicitly specified, the default values for the exit
132status, verbose level, and output stream to use are determined as
133follows:
134
135=over
136
137=item *
138
139If neither the exit status nor the verbose level is specified, then the
140default is to use an exit status of 2 with a verbose level of 0.
141
142=item *
143
144If an exit status I<is> specified but the verbose level is I<not>, then the
145verbose level will default to 1 if the exit status is less than 2 and
146will default to 0 otherwise.
147
148=item *
149
150If an exit status is I<not> specified but verbose level I<is> given, then
151the exit status will default to 2 if the verbose level is 0 and will
152default to 1 otherwise.
153
154=item *
155
156If the exit status used is less than 2, then output is printed on
157C<STDOUT>. Otherwise output is printed on C<STDERR>.
158
159=back
160
161Although the above may seem a bit confusing at first, it generally does
162"the right thing" in most situations. This determination of the default
163values to use is based upon the following typical Unix conventions:
164
165=over
166
167=item *
168
169An exit status of 0 implies "success". For example, B<diff(1)> exits
170with a status of 0 if the two files have the same contents.
171
172=item *
173
174An exit status of 1 implies possibly abnormal, but non-defective, program
175termination. For example, B<grep(1)> exits with a status of 1 if
176it did I<not> find a matching line for the given regular expression.
177
178=item *
179
180An exit status of 2 or more implies a fatal error. For example, B<ls(1)>
181exits with a status of 2 if you specify an illegal (unknown) option on
182the command line.
183
184=item *
185
186Usage messages issued as a result of bad command-line syntax should go
187to C<STDERR>. However, usage messages issued due to an explicit request
188to print usage (like specifying B<-help> on the command line) should go
189to C<STDOUT>, just in case the user wants to pipe the output to a pager
190(such as B<more(1)>).
191
192=item *
193
194If program usage has been explicitly requested by the user, it is often
195desireable to exit with a status of 1 (as opposed to 0) after issuing
196the user-requested usage message. It is also desireable to give a
197more verbose description of program usage in this case.
198
199=back
200
201B<pod2usage> doesn't force the above conventions upon you, but it will
202use them by default if you don't expressly tell it to do otherwise. The
203ability of B<pod2usage()> to accept a single number or a string makes it
204convenient to use as an innocent looking error message handling function:
205
206 use Pod::Usage;
207 use Getopt::Long;
208
209 ## Parse options
210 GetOptions("help", "man", "flag1") || pod2usage(2);
211 pod2usage(1) if ($opt_help);
212 pod2usage(-verbose => 2) if ($opt_man);
213
214 ## Check for too many filenames
215 pod2usage("$0: Too many files given.\n") if (@ARGV > 1);
216
217Some user's however may feel that the above "economy of expression" is
218not particularly readable nor consistent and may instead choose to do
219something more like the following:
220
221 use Pod::Usage;
222 use Getopt::Long;
223
224 ## Parse options
225 GetOptions("help", "man", "flag1") || pod2usage(-verbose => 0);
226 pod2usage(-verbose => 1) if ($opt_help);
227 pod2usage(-verbose => 2) if ($opt_man);
228
229 ## Check for too many filenames
230 pod2usage(-verbose => 2, -message => "$0: Too many files given.\n")
231 if (@ARGV > 1);
232
233As with all things in Perl, I<there's more than one way to do it>, and
234B<pod2usage()> adheres to this philosophy. If you are interested in
235seeing a number of different ways to invoke B<pod2usage> (although by no
236means exhaustive), please refer to L<"EXAMPLES">.
237
238=head1 EXAMPLES
239
240Each of the following invocations of C<pod2usage()> will print just the
241"SYNOPSIS" section to C<STDERR> and will exit with a status of 2:
242
243 pod2usage();
244
245 pod2usage(2);
246
247 pod2usage(-verbose => 0);
248
249 pod2usage(-exitval => 2);
250
251 pod2usage({-exitval => 2, -output => \*STDERR});
252
253 pod2usage({-verbose => 0, -output => \*STDERR});
254
255 pod2usage(-exitval => 2, -verbose => 0);
256
257 pod2usage(-exitval => 2, -verbose => 0, -output => \*STDERR);
258
259Each of the following invocations of C<pod2usage()> will print a message
260of "Syntax error." (followed by a newline) to C<STDERR>, immediately
261followed by just the "SYNOPSIS" section (also printed to C<STDERR>) and
262will exit with a status of 2:
263
264 pod2usage("Syntax error.");
265
266 pod2usage(-message => "Syntax error.", -verbose => 0);
267
268 pod2usage(-msg => "Syntax error.", -exitval => 2);
269
270 pod2usage({-msg => "Syntax error.", -exitval => 2, -output => \*STDERR});
271
272 pod2usage({-msg => "Syntax error.", -verbose => 0, -output => \*STDERR});
273
274 pod2usage(-msg => "Syntax error.", -exitval => 2, -verbose => 0);
275
276 pod2usage(-message => "Syntax error.",
277 -exitval => 2,
278 -verbose => 0,
279 -output => \*STDERR);
280
281Each of the following invocations of C<pod2usage()> will print the
282"SYNOPSIS" section and any "OPTIONS" and/or "ARGUMENTS" sections to
283C<STDOUT> and will exit with a status of 1:
284
285 pod2usage(1);
286
287 pod2usage(-verbose => 1);
288
289 pod2usage(-exitval => 1);
290
291 pod2usage({-exitval => 1, -output => \*STDOUT});
292
293 pod2usage({-verbose => 1, -output => \*STDOUT});
294
295 pod2usage(-exitval => 1, -verbose => 1);
296
297 pod2usage(-exitval => 1, -verbose => 1, -output => \*STDOUT});
298
299Each of the following invocations of C<pod2usage()> will print the
300entire manual page to C<STDOUT> and will exit with a status of 1:
301
302 pod2usage(-verbose => 2);
303
304 pod2usage({-verbose => 2, -output => \*STDOUT});
305
306 pod2usage(-exitval => 1, -verbose => 2);
307
308 pod2usage({-exitval => 1, -verbose => 2, -output => \*STDOUT});
309
310=head2 Recommended Use
311
312Most scripts should print some type of usage message to C<STDERR> when a
313command line syntax error is detected. They should also provide an
314option (usually C<-H> or C<-help>) to print a (possibly more verbose)
315usage message to C<STDOUT>. Some scripts may even wish to go so far as to
316provide a means of printing their complete documentation to C<STDOUT>
317(perhaps by allowing a C<-man> option). The following example uses
318B<Pod::Usage> in combination with B<Getopt::Long> to do all of these
319things:
320
321 use Getopt::Long;
322 use Pod::Usage;
323
324 ## Parse options and print usage if there is a syntax error,
325 ## or if usage was explicitly requested.
326 GetOptions("help", "man", "flag1") || pod2usage(2);
327 pod2usage(1) if ($opt_help);
328 pod2usage(-verbose => 2) if ($opt_man);
329
330 ## If no arguments were given, then allow STDIN to be used only
331 ## if it's not connected to a terminal (otherwise print usage)
332 pod2usage("$0: No files given.") if ((@ARGV == 0) && (-t STDIN));
333
334=head1 CAVEATS
335
336By default, B<pod2usage()> will use C<$0> as the path to the pod input
337file. Unfortunately, not all systems on which Perl runs will set C<$0>
338properly (although if C<$0> isn't found, B<pod2usage()> will search
339C<$ENV{PATH}> or else the list specified by the C<-pathlist> option).
340If this is the case for your system, you may need to explicitly specify
341the path to the pod docs for the invoking script using something
342similar to the following:
343
344 pod2usage(-exitval => 2, -input => "/path/to/your/pod/docs");
345
346=head1 AUTHOR
347
348Brad Appleton E<lt>bradapp@enteract.comE<gt>
349
350Based on code for B<Pod::Text::pod2text()> written by
351Tom Christiansen E<lt>tchrist@mox.perl.comE<gt>
352
353=head1 ACKNOWLEDGEMENTS
354
355Steven McDougall E<lt>swmcd@world.std.comE<gt> for his help and patience
356with re-writing this manpage.
357
358=cut
359
360#############################################################################
361
362use strict;
363#use diagnostics;
364use Carp;
365use Exporter;
366use Pod::PlainText;
367use File::Spec;
368
369use vars qw(@ISA @EXPORT);
370@ISA = qw(Pod::PlainText);
371@EXPORT = qw(&pod2usage);
372
373##---------------------------------------------------------------------------
374
375##---------------------------------
376## Function definitions begin here
377##---------------------------------
378
379sub pod2usage {
380 local($_) = shift || "";
381 my %opts;
382 ## Collect arguments
383 if (@_ > 0) {
384 ## Too many arguments - assume that this is a hash and
385 ## the user forgot to pass a reference to it.
386 %opts = ($_, @_);
387 }
388 elsif (ref $_) {
389 ## User passed a ref to a hash
390 %opts = %{$_} if (ref($_) eq 'HASH');
391 }
e9fdc7d2 392 elsif (/^[-+]?\d+$/) {
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393 ## User passed in the exit value to use
394 $opts{"-exitval"} = $_;
395 }
396 else {
397 ## User passed in a message to print before issuing usage.
398 $_ and $opts{"-message"} = $_;
399 }
400
401 ## Need this for backward compatibility since we formerly used
402 ## options that were all uppercase words rather than ones that
403 ## looked like Unix command-line options.
404 ## to be uppercase keywords)
405 %opts = map {
406 my $val = $opts{$_};
407 s/^(?=\w)/-/;
408 /^-msg/i and $_ = '-message';
409 /^-exit/i and $_ = '-exitval';
410 lc($_) => $val;
411 } (keys %opts);
412
413 ## Now determine default -exitval and -verbose values to use
414 if ((! defined $opts{"-exitval"}) && (! defined $opts{"-verbose"})) {
415 $opts{"-exitval"} = 2;
416 $opts{"-verbose"} = 0;
417 }
418 elsif (! defined $opts{"-exitval"}) {
419 $opts{"-exitval"} = ($opts{"-verbose"} > 0) ? 1 : 2;
420 }
421 elsif (! defined $opts{"-verbose"}) {
422 $opts{"-verbose"} = ($opts{"-exitval"} < 2);
423 }
424
425 ## Default the output file
426 $opts{"-output"} = ($opts{"-exitval"} < 2) ? \*STDOUT : \*STDERR
427 unless (defined $opts{"-output"});
428 ## Default the input file
429 $opts{"-input"} = $0 unless (defined $opts{"-input"});
430
431 ## Look up input file in path if it doesnt exist.
432 unless ((ref $opts{"-input"}) || (-e $opts{"-input"})) {
433 my ($dirname, $basename) = ('', $opts{"-input"});
434 my $pathsep = ($^O =~ /^(?:dos|os2|MSWin32)$/) ? ";"
435 : (($^O eq 'MacOS') ? ',' : ":");
436 my $pathspec = $opts{"-pathlist"} || $ENV{PATH} || $ENV{PERL5LIB};
437
438 my @paths = (ref $pathspec) ? @$pathspec : split($pathsep, $pathspec);
439 for $dirname (@paths) {
440 $_ = File::Spec->catfile($dirname, $basename) if length;
441 last if (-e $_) && ($opts{"-input"} = $_);
442 }
443 }
444
445 ## Now create a pod reader and constrain it to the desired sections.
446 my $parser = new Pod::Usage(USAGE_OPTIONS => \%opts);
447 if ($opts{"-verbose"} == 0) {
448 $parser->select("SYNOPSIS");
449 }
450 elsif ($opts{"-verbose"} == 1) {
451 my $opt_re = '(?i)' .
452 '(?:OPTIONS|ARGUMENTS)' .
453 '(?:\s*(?:AND|\/)\s*(?:OPTIONS|ARGUMENTS))?';
454 $parser->select( 'SYNOPSIS', $opt_re, "DESCRIPTION/$opt_re" );
455 }
456
457 ## Now translate the pod document and then exit with the desired status
458 $parser->parse_from_file($opts{"-input"}, $opts{"-output"});
459 exit($opts{"-exitval"});
460}
461
462##---------------------------------------------------------------------------
463
464##-------------------------------
465## Method definitions begin here
466##-------------------------------
467
468sub new {
469 my $this = shift;
470 my $class = ref($this) || $this;
471 my %params = @_;
472 my $self = {%params};
473 bless $self, $class;
474 $self->initialize();
475 return $self;
476}
477
478sub begin_pod {
479 my $self = shift;
480 $self->SUPER::begin_pod(); ## Have to call superclass
481 my $msg = $self->{USAGE_OPTIONS}->{-message} or return 1;
482 my $out_fh = $self->output_handle();
483 print $out_fh "$msg\n";
484}
485
486sub preprocess_paragraph {
487 my $self = shift;
488 local $_ = shift;
489 my $line = shift;
490 ## See if this is a heading and we arent printing the entire manpage.
e9fdc7d2 491 if (($self->{USAGE_OPTIONS}->{-verbose} < 2) && /^=head/) {
360aca43 492 ## Change the title of the SYNOPSIS section to USAGE
e9fdc7d2 493 s/^=head1\s+SYNOPSIS\s*$/=head1 USAGE/;
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494 ## Try to do some lowercasing instead of all-caps in headings
495 s{([A-Z])([A-Z]+)}{((length($2) > 2) ? $1 : lc($1)) . lc($2)}ge;
496 ## Use a colon to end all headings
e9fdc7d2 497 s/\s*$/:/ unless (/:\s*$/);
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498 $_ .= "\n";
499 }
500 return $self->SUPER::preprocess_paragraph($_);
501}
502