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86530b38 AT |
1 | package diagnostics; |
2 | ||
3 | =head1 NAME | |
4 | ||
5 | diagnostics - Perl compiler pragma to force verbose warning diagnostics | |
6 | ||
7 | splain - standalone program to do the same thing | |
8 | ||
9 | =head1 SYNOPSIS | |
10 | ||
11 | As a pragma: | |
12 | ||
13 | use diagnostics; | |
14 | use diagnostics -verbose; | |
15 | ||
16 | enable diagnostics; | |
17 | disable diagnostics; | |
18 | ||
19 | Aa a program: | |
20 | ||
21 | perl program 2>diag.out | |
22 | splain [-v] [-p] diag.out | |
23 | ||
24 | ||
25 | =head1 DESCRIPTION | |
26 | ||
27 | =head2 The C<diagnostics> Pragma | |
28 | ||
29 | This module extends the terse diagnostics normally emitted by both the | |
30 | perl compiler and the perl interpreter, augmenting them with the more | |
31 | explicative and endearing descriptions found in L<perldiag>. Like the | |
32 | other pragmata, it affects the compilation phase of your program rather | |
33 | than merely the execution phase. | |
34 | ||
35 | To use in your program as a pragma, merely invoke | |
36 | ||
37 | use diagnostics; | |
38 | ||
39 | at the start (or near the start) of your program. (Note | |
40 | that this I<does> enable perl's B<-w> flag.) Your whole | |
41 | compilation will then be subject(ed :-) to the enhanced diagnostics. | |
42 | These still go out B<STDERR>. | |
43 | ||
44 | Due to the interaction between runtime and compiletime issues, | |
45 | and because it's probably not a very good idea anyway, | |
46 | you may not use C<no diagnostics> to turn them off at compiletime. | |
47 | However, you may control their behaviour at runtime using the | |
48 | disable() and enable() methods to turn them off and on respectively. | |
49 | ||
50 | The B<-verbose> flag first prints out the L<perldiag> introduction before | |
51 | any other diagnostics. The $diagnostics::PRETTY variable can generate nicer | |
52 | escape sequences for pagers. | |
53 | ||
54 | Warnings dispatched from perl itself (or more accurately, those that match | |
55 | descriptions found in L<perldiag>) are only displayed once (no duplicate | |
56 | descriptions). User code generated warnings ala warn() are unaffected, | |
57 | allowing duplicate user messages to be displayed. | |
58 | ||
59 | =head2 The I<splain> Program | |
60 | ||
61 | While apparently a whole nuther program, I<splain> is actually nothing | |
62 | more than a link to the (executable) F<diagnostics.pm> module, as well as | |
63 | a link to the F<diagnostics.pod> documentation. The B<-v> flag is like | |
64 | the C<use diagnostics -verbose> directive. | |
65 | The B<-p> flag is like the | |
66 | $diagnostics::PRETTY variable. Since you're post-processing with | |
67 | I<splain>, there's no sense in being able to enable() or disable() processing. | |
68 | ||
69 | Output from I<splain> is directed to B<STDOUT>, unlike the pragma. | |
70 | ||
71 | =head1 EXAMPLES | |
72 | ||
73 | The following file is certain to trigger a few errors at both | |
74 | runtime and compiletime: | |
75 | ||
76 | use diagnostics; | |
77 | print NOWHERE "nothing\n"; | |
78 | print STDERR "\n\tThis message should be unadorned.\n"; | |
79 | warn "\tThis is a user warning"; | |
80 | print "\nDIAGNOSTIC TESTER: Please enter a <CR> here: "; | |
81 | my $a, $b = scalar <STDIN>; | |
82 | print "\n"; | |
83 | print $x/$y; | |
84 | ||
85 | If you prefer to run your program first and look at its problem | |
86 | afterwards, do this: | |
87 | ||
88 | perl -w test.pl 2>test.out | |
89 | ./splain < test.out | |
90 | ||
91 | Note that this is not in general possible in shells of more dubious heritage, | |
92 | as the theoretical | |
93 | ||
94 | (perl -w test.pl >/dev/tty) >& test.out | |
95 | ./splain < test.out | |
96 | ||
97 | Because you just moved the existing B<stdout> to somewhere else. | |
98 | ||
99 | If you don't want to modify your source code, but still have on-the-fly | |
100 | warnings, do this: | |
101 | ||
102 | exec 3>&1; perl -w test.pl 2>&1 1>&3 3>&- | splain 1>&2 3>&- | |
103 | ||
104 | Nifty, eh? | |
105 | ||
106 | If you want to control warnings on the fly, do something like this. | |
107 | Make sure you do the C<use> first, or you won't be able to get | |
108 | at the enable() or disable() methods. | |
109 | ||
110 | use diagnostics; # checks entire compilation phase | |
111 | print "\ntime for 1st bogus diags: SQUAWKINGS\n"; | |
112 | print BOGUS1 'nada'; | |
113 | print "done with 1st bogus\n"; | |
114 | ||
115 | disable diagnostics; # only turns off runtime warnings | |
116 | print "\ntime for 2nd bogus: (squelched)\n"; | |
117 | print BOGUS2 'nada'; | |
118 | print "done with 2nd bogus\n"; | |
119 | ||
120 | enable diagnostics; # turns back on runtime warnings | |
121 | print "\ntime for 3rd bogus: SQUAWKINGS\n"; | |
122 | print BOGUS3 'nada'; | |
123 | print "done with 3rd bogus\n"; | |
124 | ||
125 | disable diagnostics; | |
126 | print "\ntime for 4th bogus: (squelched)\n"; | |
127 | print BOGUS4 'nada'; | |
128 | print "done with 4th bogus\n"; | |
129 | ||
130 | =head1 INTERNALS | |
131 | ||
132 | Diagnostic messages derive from the F<perldiag.pod> file when available at | |
133 | runtime. Otherwise, they may be embedded in the file itself when the | |
134 | splain package is built. See the F<Makefile> for details. | |
135 | ||
136 | If an extant $SIG{__WARN__} handler is discovered, it will continue | |
137 | to be honored, but only after the diagnostics::splainthis() function | |
138 | (the module's $SIG{__WARN__} interceptor) has had its way with your | |
139 | warnings. | |
140 | ||
141 | There is a $diagnostics::DEBUG variable you may set if you're desperately | |
142 | curious what sorts of things are being intercepted. | |
143 | ||
144 | BEGIN { $diagnostics::DEBUG = 1 } | |
145 | ||
146 | ||
147 | =head1 BUGS | |
148 | ||
149 | Not being able to say "no diagnostics" is annoying, but may not be | |
150 | insurmountable. | |
151 | ||
152 | The C<-pretty> directive is called too late to affect matters. | |
153 | You have to do this instead, and I<before> you load the module. | |
154 | ||
155 | BEGIN { $diagnostics::PRETTY = 1 } | |
156 | ||
157 | I could start up faster by delaying compilation until it should be | |
158 | needed, but this gets a "panic: top_level" when using the pragma form | |
159 | in Perl 5.001e. | |
160 | ||
161 | While it's true that this documentation is somewhat subserious, if you use | |
162 | a program named I<splain>, you should expect a bit of whimsy. | |
163 | ||
164 | =head1 AUTHOR | |
165 | ||
166 | Tom Christiansen <F<tchrist@mox.perl.com>>, 25 June 1995. | |
167 | ||
168 | =cut | |
169 | ||
170 | use strict; | |
171 | use 5.006; | |
172 | use Carp; | |
173 | ||
174 | our $VERSION = 1.1; | |
175 | our $DEBUG; | |
176 | our $VERBOSE; | |
177 | our $PRETTY; | |
178 | ||
179 | use Config; | |
180 | my($privlib, $archlib) = @Config{qw(privlibexp archlibexp)}; | |
181 | if ($^O eq 'VMS') { | |
182 | require VMS::Filespec; | |
183 | $privlib = VMS::Filespec::unixify($privlib); | |
184 | $archlib = VMS::Filespec::unixify($archlib); | |
185 | } | |
186 | my @trypod = ( | |
187 | "$archlib/pod/perldiag.pod", | |
188 | "$privlib/pod/perldiag-$Config{version}.pod", | |
189 | "$privlib/pod/perldiag.pod", | |
190 | "$archlib/pods/perldiag.pod", | |
191 | "$privlib/pods/perldiag-$Config{version}.pod", | |
192 | "$privlib/pods/perldiag.pod", | |
193 | ); | |
194 | # handy for development testing of new warnings etc | |
195 | unshift @trypod, "./pod/perldiag.pod" if -e "pod/perldiag.pod"; | |
196 | (my $PODFILE) = ((grep { -e } @trypod), $trypod[$#trypod])[0]; | |
197 | ||
198 | if ($^O eq 'MacOS') { | |
199 | # just updir one from each lib dir, we'll find it ... | |
200 | ($PODFILE) = grep { -e } map { "$_:pod:perldiag.pod" } @INC; | |
201 | } | |
202 | ||
203 | ||
204 | $DEBUG ||= 0; | |
205 | my $WHOAMI = ref bless []; # nobody's business, prolly not even mine | |
206 | ||
207 | local $| = 1; | |
208 | local $_; | |
209 | ||
210 | my $standalone; | |
211 | my(%HTML_2_Troff, %HTML_2_Latin_1, %HTML_2_ASCII_7); | |
212 | ||
213 | CONFIG: { | |
214 | our $opt_p = our $opt_d = our $opt_v = our $opt_f = ''; | |
215 | ||
216 | unless (caller) { | |
217 | $standalone++; | |
218 | require Getopt::Std; | |
219 | Getopt::Std::getopts('pdvf:') | |
220 | or die "Usage: $0 [-v] [-p] [-f splainpod]"; | |
221 | $PODFILE = $opt_f if $opt_f; | |
222 | $DEBUG = 2 if $opt_d; | |
223 | $VERBOSE = $opt_v; | |
224 | $PRETTY = $opt_p; | |
225 | } | |
226 | ||
227 | if (open(POD_DIAG, $PODFILE)) { | |
228 | warn "Happy happy podfile from real $PODFILE\n" if $DEBUG; | |
229 | last CONFIG; | |
230 | } | |
231 | ||
232 | if (caller) { | |
233 | INCPATH: { | |
234 | for my $file ( (map { "$_/$WHOAMI.pm" } @INC), $0) { | |
235 | warn "Checking $file\n" if $DEBUG; | |
236 | if (open(POD_DIAG, $file)) { | |
237 | while (<POD_DIAG>) { | |
238 | next unless | |
239 | /^__END__\s*# wish diag dbase were more accessible/; | |
240 | print STDERR "podfile is $file\n" if $DEBUG; | |
241 | last INCPATH; | |
242 | } | |
243 | } | |
244 | } | |
245 | } | |
246 | } else { | |
247 | print STDERR "podfile is <DATA>\n" if $DEBUG; | |
248 | *POD_DIAG = *main::DATA; | |
249 | } | |
250 | } | |
251 | if (eof(POD_DIAG)) { | |
252 | die "couldn't find diagnostic data in $PODFILE @INC $0"; | |
253 | } | |
254 | ||
255 | ||
256 | %HTML_2_Troff = ( | |
257 | 'amp' => '&', # ampersand | |
258 | 'lt' => '<', # left chevron, less-than | |
259 | 'gt' => '>', # right chevron, greater-than | |
260 | 'quot' => '"', # double quote | |
261 | ||
262 | "Aacute" => "A\\*'", # capital A, acute accent | |
263 | # etc | |
264 | ||
265 | ); | |
266 | ||
267 | %HTML_2_Latin_1 = ( | |
268 | 'amp' => '&', # ampersand | |
269 | 'lt' => '<', # left chevron, less-than | |
270 | 'gt' => '>', # right chevron, greater-than | |
271 | 'quot' => '"', # double quote | |
272 | ||
273 | "Aacute" => "\xC1" # capital A, acute accent | |
274 | ||
275 | # etc | |
276 | ); | |
277 | ||
278 | %HTML_2_ASCII_7 = ( | |
279 | 'amp' => '&', # ampersand | |
280 | 'lt' => '<', # left chevron, less-than | |
281 | 'gt' => '>', # right chevron, greater-than | |
282 | 'quot' => '"', # double quote | |
283 | ||
284 | "Aacute" => "A" # capital A, acute accent | |
285 | # etc | |
286 | ); | |
287 | ||
288 | our %HTML_Escapes; | |
289 | *HTML_Escapes = do { | |
290 | if ($standalone) { | |
291 | $PRETTY ? \%HTML_2_Latin_1 : \%HTML_2_ASCII_7; | |
292 | } else { | |
293 | \%HTML_2_Latin_1; | |
294 | } | |
295 | }; | |
296 | ||
297 | *THITHER = $standalone ? *STDOUT : *STDERR; | |
298 | ||
299 | my $transmo = <<EOFUNC; | |
300 | sub transmo { | |
301 | #local \$^W = 0; # recursive warnings we do NOT need! | |
302 | study; | |
303 | EOFUNC | |
304 | ||
305 | my %msg; | |
306 | { | |
307 | print STDERR "FINISHING COMPILATION for $_\n" if $DEBUG; | |
308 | local $/ = ''; | |
309 | local $_; | |
310 | my $header; | |
311 | my $for_item; | |
312 | while (<POD_DIAG>) { | |
313 | ||
314 | unescape(); | |
315 | if ($PRETTY) { | |
316 | sub noop { return $_[0] } # spensive for a noop | |
317 | sub bold { my $str =$_[0]; $str =~ s/(.)/$1\b$1/g; return $str; } | |
318 | sub italic { my $str = $_[0]; $str =~ s/(.)/_\b$1/g; return $str; } | |
319 | s/[BC]<(.*?)>/bold($1)/ges; | |
320 | s/[LIF]<(.*?)>/italic($1)/ges; | |
321 | } else { | |
322 | s/[BC]<(.*?)>/$1/gs; | |
323 | s/[LIF]<(.*?)>/$1/gs; | |
324 | } | |
325 | unless (/^=/) { | |
326 | if (defined $header) { | |
327 | if ( $header eq 'DESCRIPTION' && | |
328 | ( /Optional warnings are enabled/ | |
329 | || /Some of these messages are generic./ | |
330 | ) ) | |
331 | { | |
332 | next; | |
333 | } | |
334 | s/^/ /gm; | |
335 | $msg{$header} .= $_; | |
336 | undef $for_item; | |
337 | } | |
338 | next; | |
339 | } | |
340 | unless ( s/=item (.*?)\s*\z//) { | |
341 | ||
342 | if ( s/=head1\sDESCRIPTION//) { | |
343 | $msg{$header = 'DESCRIPTION'} = ''; | |
344 | undef $for_item; | |
345 | } | |
346 | elsif( s/^=for\s+diagnostics\s*\n(.*?)\s*\z// ) { | |
347 | $for_item = $1; | |
348 | } | |
349 | next; | |
350 | } | |
351 | ||
352 | if( $for_item ) { $header = $for_item; undef $for_item } | |
353 | else { | |
354 | $header = $1; | |
355 | while( $header =~ /[;,]\z/ ) { | |
356 | <POD_DIAG> =~ /^\s*(.*?)\s*\z/; | |
357 | $header .= ' '.$1; | |
358 | } | |
359 | } | |
360 | ||
361 | # strip formatting directives in =item line | |
362 | $header =~ s/[A-Z]<(.*?)>/$1/g; | |
363 | ||
364 | if ($header =~ /%[csd]/) { | |
365 | my $rhs = my $lhs = $header; | |
366 | if ($lhs =~ s/(.*?)%d(?!%d)(.*)/\Q$1\E-?\\d+\Q$2\E/g) { | |
367 | $lhs =~ s/\\%s/.*?/g; | |
368 | } else { | |
369 | # if i had lookbehind negations, | |
370 | # i wouldn't have to do this \377 noise | |
371 | $lhs =~ s/(.*?)%s/\Q$1\E.*?\377/g; | |
372 | $lhs =~ s/\377([^\377]*)$/\Q$1\E/; | |
373 | $lhs =~ s/\377//g; | |
374 | $lhs =~ s/\.\*\?$/.*/; # Allow %s at the end to eat it all | |
375 | } | |
376 | $lhs =~ s/\\%c/./g; | |
377 | $transmo .= " s{^$lhs}\n {\Q$rhs\E}s\n\t&& return 1;\n"; | |
378 | } else { | |
379 | $transmo .= " m{^\Q$header\E} && return 1;\n"; | |
380 | } | |
381 | ||
382 | print STDERR "$WHOAMI: Duplicate entry: \"$header\"\n" | |
383 | if $msg{$header}; | |
384 | ||
385 | $msg{$header} = ''; | |
386 | } | |
387 | ||
388 | ||
389 | close POD_DIAG unless *main::DATA eq *POD_DIAG; | |
390 | ||
391 | die "No diagnostics?" unless %msg; | |
392 | ||
393 | $transmo .= " return 0;\n}\n"; | |
394 | print STDERR $transmo if $DEBUG; | |
395 | eval $transmo; | |
396 | die $@ if $@; | |
397 | } | |
398 | ||
399 | if ($standalone) { | |
400 | if (!@ARGV and -t STDIN) { print STDERR "$0: Reading from STDIN\n" } | |
401 | while (defined (my $error = <>)) { | |
402 | splainthis($error) || print THITHER $error; | |
403 | } | |
404 | exit; | |
405 | } | |
406 | ||
407 | my $olddie; | |
408 | my $oldwarn; | |
409 | ||
410 | sub import { | |
411 | shift; | |
412 | $^W = 1; # yup, clobbered the global variable; | |
413 | # tough, if you want diags, you want diags. | |
414 | return if defined $SIG{__WARN__} && ($SIG{__WARN__} eq \&warn_trap); | |
415 | ||
416 | for (@_) { | |
417 | ||
418 | /^-d(ebug)?$/ && do { | |
419 | $DEBUG++; | |
420 | next; | |
421 | }; | |
422 | ||
423 | /^-v(erbose)?$/ && do { | |
424 | $VERBOSE++; | |
425 | next; | |
426 | }; | |
427 | ||
428 | /^-p(retty)?$/ && do { | |
429 | print STDERR "$0: I'm afraid it's too late for prettiness.\n"; | |
430 | $PRETTY++; | |
431 | next; | |
432 | }; | |
433 | ||
434 | warn "Unknown flag: $_"; | |
435 | } | |
436 | ||
437 | $oldwarn = $SIG{__WARN__}; | |
438 | $olddie = $SIG{__DIE__}; | |
439 | $SIG{__WARN__} = \&warn_trap; | |
440 | $SIG{__DIE__} = \&death_trap; | |
441 | } | |
442 | ||
443 | sub enable { &import } | |
444 | ||
445 | sub disable { | |
446 | shift; | |
447 | return unless $SIG{__WARN__} eq \&warn_trap; | |
448 | $SIG{__WARN__} = $oldwarn || ''; | |
449 | $SIG{__DIE__} = $olddie || ''; | |
450 | } | |
451 | ||
452 | sub warn_trap { | |
453 | my $warning = $_[0]; | |
454 | if (caller eq $WHOAMI or !splainthis($warning)) { | |
455 | print STDERR $warning; | |
456 | } | |
457 | &$oldwarn if defined $oldwarn and $oldwarn and $oldwarn ne \&warn_trap; | |
458 | }; | |
459 | ||
460 | sub death_trap { | |
461 | my $exception = $_[0]; | |
462 | ||
463 | # See if we are coming from anywhere within an eval. If so we don't | |
464 | # want to explain the exception because it's going to get caught. | |
465 | my $in_eval = 0; | |
466 | my $i = 0; | |
467 | while (1) { | |
468 | my $caller = (caller($i++))[3] or last; | |
469 | if ($caller eq '(eval)') { | |
470 | $in_eval = 1; | |
471 | last; | |
472 | } | |
473 | } | |
474 | ||
475 | splainthis($exception) unless $in_eval; | |
476 | if (caller eq $WHOAMI) { print STDERR "INTERNAL EXCEPTION: $exception"; } | |
477 | &$olddie if defined $olddie and $olddie and $olddie ne \&death_trap; | |
478 | ||
479 | return if $in_eval; | |
480 | ||
481 | # We don't want to unset these if we're coming from an eval because | |
482 | # then we've turned off diagnostics. | |
483 | ||
484 | # Switch off our die/warn handlers so we don't wind up in our own | |
485 | # traps. | |
486 | $SIG{__DIE__} = $SIG{__WARN__} = ''; | |
487 | ||
488 | # Have carp skip over death_trap() when showing the stack trace. | |
489 | local($Carp::CarpLevel) = 1; | |
490 | ||
491 | confess "Uncaught exception from user code:\n\t$exception"; | |
492 | # up we go; where we stop, nobody knows, but i think we die now | |
493 | # but i'm deeply afraid of the &$olddie guy reraising and us getting | |
494 | # into an indirect recursion loop | |
495 | }; | |
496 | ||
497 | my %exact_duplicate; | |
498 | my %old_diag; | |
499 | my $count; | |
500 | my $wantspace; | |
501 | sub splainthis { | |
502 | local $_ = shift; | |
503 | local $\; | |
504 | ### &finish_compilation unless %msg; | |
505 | s/\.?\n+$//; | |
506 | my $orig = $_; | |
507 | # return unless defined; | |
508 | s/, <.*?> (?:line|chunk).*$//; | |
509 | my $real = s/(.*?) at .*? (?:line|chunk) \d+.*/$1/; | |
510 | s/^\((.*)\)$/$1/; | |
511 | if ($exact_duplicate{$orig}++) { | |
512 | return &transmo; | |
513 | } | |
514 | else { | |
515 | return 0 unless &transmo; | |
516 | } | |
517 | $orig = shorten($orig); | |
518 | if ($old_diag{$_}) { | |
519 | autodescribe(); | |
520 | print THITHER "$orig (#$old_diag{$_})\n"; | |
521 | $wantspace = 1; | |
522 | } else { | |
523 | autodescribe(); | |
524 | $old_diag{$_} = ++$count; | |
525 | print THITHER "\n" if $wantspace; | |
526 | $wantspace = 0; | |
527 | print THITHER "$orig (#$old_diag{$_})\n"; | |
528 | if ($msg{$_}) { | |
529 | print THITHER $msg{$_}; | |
530 | } else { | |
531 | if (0 and $standalone) { | |
532 | print THITHER " **** Error #$old_diag{$_} ", | |
533 | ($real ? "is" : "appears to be"), | |
534 | " an unknown diagnostic message.\n\n"; | |
535 | } | |
536 | return 0; | |
537 | } | |
538 | } | |
539 | return 1; | |
540 | } | |
541 | ||
542 | sub autodescribe { | |
543 | if ($VERBOSE and not $count) { | |
544 | print THITHER &{$PRETTY ? \&bold : \&noop}("DESCRIPTION OF DIAGNOSTICS"), | |
545 | "\n$msg{DESCRIPTION}\n"; | |
546 | } | |
547 | } | |
548 | ||
549 | sub unescape { | |
550 | s { | |
551 | E< | |
552 | ( [A-Za-z]+ ) | |
553 | > | |
554 | } { | |
555 | do { | |
556 | exists $HTML_Escapes{$1} | |
557 | ? do { $HTML_Escapes{$1} } | |
558 | : do { | |
559 | warn "Unknown escape: E<$1> in $_"; | |
560 | "E<$1>"; | |
561 | } | |
562 | } | |
563 | }egx; | |
564 | } | |
565 | ||
566 | sub shorten { | |
567 | my $line = $_[0]; | |
568 | if (length($line) > 79 and index($line, "\n") == -1) { | |
569 | my $space_place = rindex($line, ' ', 79); | |
570 | if ($space_place != -1) { | |
571 | substr($line, $space_place, 1) = "\n\t"; | |
572 | } | |
573 | } | |
574 | return $line; | |
575 | } | |
576 | ||
577 | ||
578 | 1 unless $standalone; # or it'll complain about itself | |
579 | __END__ # wish diag dbase were more accessible |