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4633a7c4 | 1 | package diagnostics; |
4633a7c4 LW |
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 | |
1fef88e7 | 30 | perl compiler and the perl interpeter, augmenting them with the more |
4633a7c4 | 31 | explicative and endearing descriptions found in L<perldiag>. Like the |
1fef88e7 | 32 | other pragmata, it affects the compilation phase of your program rather |
4633a7c4 LW |
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 there 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 | |
1fef88e7 JM |
51 | any other diagnostics. The $diagnostics::PRETTY variable can generate nicer |
52 | escape sequences for pagers. | |
4633a7c4 LW |
53 | |
54 | =head2 The I<splain> Program | |
55 | ||
56 | While apparently a whole nuther program, I<splain> is actually nothing | |
57 | more than a link to the (executable) F<diagnostics.pm> module, as well as | |
58 | a link to the F<diagnostics.pod> documentation. The B<-v> flag is like | |
59 | the C<use diagnostics -verbose> directive. | |
60 | The B<-p> flag is like the | |
61 | $diagnostics::PRETTY variable. Since you're post-processing with | |
62 | I<splain>, there's no sense in being able to enable() or disable() processing. | |
63 | ||
64 | Output from I<splain> is directed to B<STDOUT>, unlike the pragma. | |
65 | ||
66 | =head1 EXAMPLES | |
67 | ||
68 | The following file is certain to trigger a few errors at both | |
69 | runtime and compiletime: | |
70 | ||
71 | use diagnostics; | |
72 | print NOWHERE "nothing\n"; | |
73 | print STDERR "\n\tThis message should be unadorned.\n"; | |
74 | warn "\tThis is a user warning"; | |
75 | print "\nDIAGNOSTIC TESTER: Please enter a <CR> here: "; | |
76 | my $a, $b = scalar <STDIN>; | |
77 | print "\n"; | |
78 | print $x/$y; | |
79 | ||
80 | If you prefer to run your program first and look at its problem | |
81 | afterwards, do this: | |
82 | ||
83 | perl -w test.pl 2>test.out | |
84 | ./splain < test.out | |
85 | ||
86 | Note that this is not in general possible in shells of more dubious heritage, | |
1fef88e7 | 87 | as the theoretical |
4633a7c4 LW |
88 | |
89 | (perl -w test.pl >/dev/tty) >& test.out | |
90 | ./splain < test.out | |
91 | ||
92 | Because you just moved the existing B<stdout> to somewhere else. | |
93 | ||
94 | If you don't want to modify your source code, but still have on-the-fly | |
95 | warnings, do this: | |
96 | ||
97 | exec 3>&1; perl -w test.pl 2>&1 1>&3 3>&- | splain 1>&2 3>&- | |
98 | ||
99 | Nifty, eh? | |
100 | ||
101 | If you want to control warnings on the fly, do something like this. | |
102 | Make sure you do the C<use> first, or you won't be able to get | |
103 | at the enable() or disable() methods. | |
104 | ||
105 | use diagnostics; # checks entire compilation phase | |
106 | print "\ntime for 1st bogus diags: SQUAWKINGS\n"; | |
107 | print BOGUS1 'nada'; | |
108 | print "done with 1st bogus\n"; | |
109 | ||
110 | disable diagnostics; # only turns off runtime warnings | |
111 | print "\ntime for 2nd bogus: (squelched)\n"; | |
112 | print BOGUS2 'nada'; | |
113 | print "done with 2nd bogus\n"; | |
114 | ||
115 | enable diagnostics; # turns back on runtime warnings | |
116 | print "\ntime for 3rd bogus: SQUAWKINGS\n"; | |
117 | print BOGUS3 'nada'; | |
118 | print "done with 3rd bogus\n"; | |
119 | ||
120 | disable diagnostics; | |
121 | print "\ntime for 4th bogus: (squelched)\n"; | |
122 | print BOGUS4 'nada'; | |
123 | print "done with 4th bogus\n"; | |
124 | ||
125 | =head1 INTERNALS | |
126 | ||
127 | Diagnostic messages derive from the F<perldiag.pod> file when available at | |
128 | runtime. Otherwise, they may be embedded in the file itself when the | |
129 | splain package is built. See the F<Makefile> for details. | |
130 | ||
131 | If an extant $SIG{__WARN__} handler is discovered, it will continue | |
1fef88e7 | 132 | to be honored, but only after the diagnostics::splainthis() function |
4633a7c4 LW |
133 | (the module's $SIG{__WARN__} interceptor) has had its way with your |
134 | warnings. | |
135 | ||
136 | There is a $diagnostics::DEBUG variable you may set if you're desperately | |
137 | curious what sorts of things are being intercepted. | |
138 | ||
139 | BEGIN { $diagnostics::DEBUG = 1 } | |
140 | ||
141 | ||
142 | =head1 BUGS | |
143 | ||
144 | Not being able to say "no diagnostics" is annoying, but may not be | |
145 | insurmountable. | |
146 | ||
147 | The C<-pretty> directive is called too late to affect matters. | |
148 | You have to to this instead, and I<before> you load the module. | |
149 | ||
150 | BEGIN { $diagnostics::PRETTY = 1 } | |
151 | ||
152 | I could start up faster by delaying compilation until it should be | |
a6006777 | 153 | needed, but this gets a "panic: top_level" when using the pragma form |
154 | in Perl 5.001e. | |
4633a7c4 LW |
155 | |
156 | While it's true that this documentation is somewhat subserious, if you use | |
157 | a program named I<splain>, you should expect a bit of whimsy. | |
158 | ||
159 | =head1 AUTHOR | |
160 | ||
352854fa | 161 | Tom Christiansen <F<tchrist@mox.perl.com>>, 25 June 1995. |
4633a7c4 LW |
162 | |
163 | =cut | |
164 | ||
5f05dabc | 165 | require 5.001; |
5f05dabc | 166 | use Carp; |
167 | ||
168 | use Config; | |
91a06757 | 169 | ($privlib, $archlib) = @Config{qw(privlibexp archlibexp)}; |
5f05dabc | 170 | if ($^O eq 'VMS') { |
91a06757 CS |
171 | require VMS::Filespec; |
172 | $privlib = VMS::Filespec::unixify($privlib); | |
173 | $archlib = VMS::Filespec::unixify($archlib); | |
5f05dabc | 174 | } |
91a06757 CS |
175 | @trypod = ("$archlib/pod/perldiag.pod", |
176 | "$privlib/pod/perldiag-$].pod", | |
177 | "$privlib/pod/perldiag.pod"); | |
178 | ($PODFILE) = ((grep { -e } @trypod), $trypod[$#trypod])[0]; | |
5f05dabc | 179 | |
4633a7c4 LW |
180 | $DEBUG ||= 0; |
181 | my $WHOAMI = ref bless []; # nobody's business, prolly not even mine | |
182 | ||
6dab8668 | 183 | $| = 1; |
4633a7c4 LW |
184 | |
185 | local $_; | |
186 | ||
187 | CONFIG: { | |
188 | $opt_p = $opt_d = $opt_v = $opt_f = ''; | |
189 | %HTML_2_Troff = %HTML_2_Latin_1 = %HTML_2_ASCII_7 = (); | |
190 | %exact_duplicate = (); | |
191 | ||
192 | unless (caller) { | |
193 | $standalone++; | |
194 | require Getopt::Std; | |
91a06757 CS |
195 | Getopt::Std::getopts('pdvf:') |
196 | or die "Usage: $0 [-v] [-p] [-f splainpod]"; | |
4633a7c4 LW |
197 | $PODFILE = $opt_f if $opt_f; |
198 | $DEBUG = 2 if $opt_d; | |
199 | $VERBOSE = $opt_v; | |
200 | $PRETTY = $opt_p; | |
201 | } | |
202 | ||
203 | if (open(POD_DIAG, $PODFILE)) { | |
204 | warn "Happy happy podfile from real $PODFILE\n" if $DEBUG; | |
205 | last CONFIG; | |
206 | } | |
207 | ||
208 | if (caller) { | |
209 | INCPATH: { | |
210 | for $file ( (map { "$_/$WHOAMI.pm" } @INC), $0) { | |
211 | warn "Checking $file\n" if $DEBUG; | |
212 | if (open(POD_DIAG, $file)) { | |
213 | while (<POD_DIAG>) { | |
214 | next unless /^__END__\s*# wish diag dbase were more accessible/; | |
215 | print STDERR "podfile is $file\n" if $DEBUG; | |
216 | last INCPATH; | |
217 | } | |
218 | } | |
219 | } | |
220 | } | |
221 | } else { | |
222 | print STDERR "podfile is <DATA>\n" if $DEBUG; | |
223 | *POD_DIAG = *main::DATA; | |
224 | } | |
225 | } | |
226 | if (eof(POD_DIAG)) { | |
227 | die "couldn't find diagnostic data in $PODFILE @INC $0"; | |
228 | } | |
229 | ||
230 | ||
231 | %HTML_2_Troff = ( | |
232 | 'amp' => '&', # ampersand | |
233 | 'lt' => '<', # left chevron, less-than | |
234 | 'gt' => '>', # right chevron, greater-than | |
235 | 'quot' => '"', # double quote | |
236 | ||
237 | "Aacute" => "A\\*'", # capital A, acute accent | |
238 | # etc | |
239 | ||
240 | ); | |
241 | ||
242 | %HTML_2_Latin_1 = ( | |
243 | 'amp' => '&', # ampersand | |
244 | 'lt' => '<', # left chevron, less-than | |
245 | 'gt' => '>', # right chevron, greater-than | |
246 | 'quot' => '"', # double quote | |
247 | ||
248 | "Aacute" => "\xC1" # capital A, acute accent | |
249 | ||
250 | # etc | |
251 | ); | |
252 | ||
253 | %HTML_2_ASCII_7 = ( | |
254 | 'amp' => '&', # ampersand | |
255 | 'lt' => '<', # left chevron, less-than | |
256 | 'gt' => '>', # right chevron, greater-than | |
257 | 'quot' => '"', # double quote | |
258 | ||
259 | "Aacute" => "A" # capital A, acute accent | |
260 | # etc | |
261 | ); | |
262 | ||
263 | *HTML_Escapes = do { | |
264 | if ($standalone) { | |
265 | $PRETTY ? \%HTML_2_Latin_1 : \%HTML_2_ASCII_7; | |
266 | } else { | |
267 | \%HTML_2_Latin_1; | |
268 | } | |
269 | }; | |
270 | ||
271 | *THITHER = $standalone ? *STDOUT : *STDERR; | |
272 | ||
273 | $transmo = <<EOFUNC; | |
274 | sub transmo { | |
275 | local \$^W = 0; # recursive warnings we do NOT need! | |
276 | study; | |
277 | EOFUNC | |
278 | ||
279 | ### sub finish_compilation { # 5.001e panic: top_level for embedded version | |
280 | print STDERR "FINISHING COMPILATION for $_\n" if $DEBUG; | |
281 | ### local | |
282 | $RS = ''; | |
283 | local $_; | |
284 | while (<POD_DIAG>) { | |
285 | #s/(.*)\n//; | |
286 | #$header = $1; | |
287 | ||
288 | unescape(); | |
289 | if ($PRETTY) { | |
290 | sub noop { return $_[0] } # spensive for a noop | |
291 | sub bold { my $str =$_[0]; $str =~ s/(.)/$1\b$1/g; return $str; } | |
292 | sub italic { my $str = $_[0]; $str =~ s/(.)/_\b$1/g; return $str; } | |
293 | s/[BC]<(.*?)>/bold($1)/ges; | |
294 | s/[LIF]<(.*?)>/italic($1)/ges; | |
295 | } else { | |
296 | s/[BC]<(.*?)>/$1/gs; | |
297 | s/[LIF]<(.*?)>/$1/gs; | |
298 | } | |
299 | unless (/^=/) { | |
300 | if (defined $header) { | |
301 | if ( $header eq 'DESCRIPTION' && | |
302 | ( /Optional warnings are enabled/ | |
303 | || /Some of these messages are generic./ | |
304 | ) ) | |
305 | { | |
306 | next; | |
307 | } | |
308 | s/^/ /gm; | |
309 | $msg{$header} .= $_; | |
310 | } | |
311 | next; | |
312 | } | |
313 | unless ( s/=item (.*)\s*\Z//) { | |
314 | ||
315 | if ( s/=head1\sDESCRIPTION//) { | |
316 | $msg{$header = 'DESCRIPTION'} = ''; | |
317 | } | |
318 | next; | |
319 | } | |
4fdae800 | 320 | |
321 | # strip formatting directives in =item line | |
322 | ($header = $1) =~ s/[A-Z]<(.*?)>/$1/g; | |
4633a7c4 LW |
323 | |
324 | if ($header =~ /%[sd]/) { | |
325 | $rhs = $lhs = $header; | |
326 | #if ($lhs =~ s/(.*?)%d(?!%d)(.*)/\Q$1\E\\d+\Q$2\E\$/g) { | |
327 | if ($lhs =~ s/(.*?)%d(?!%d)(.*)/\Q$1\E\\d+\Q$2\E/g) { | |
328 | $lhs =~ s/\\%s/.*?/g; | |
329 | } else { | |
330 | # if i had lookbehind negations, i wouldn't have to do this \377 noise | |
331 | $lhs =~ s/(.*?)%s/\Q$1\E.*?\377/g; | |
332 | #$lhs =~ s/\377([^\377]*)$/\Q$1\E\$/; | |
333 | $lhs =~ s/\377([^\377]*)$/\Q$1\E/; | |
334 | $lhs =~ s/\377//g; | |
e7ea3e70 | 335 | $lhs =~ s/\.\*\?$/.*/; # Allow %s at the end to eat it all |
4633a7c4 | 336 | } |
e7ea3e70 | 337 | $transmo .= " s{^$lhs}\n {\Q$rhs\E}s\n\t&& return 1;\n"; |
4633a7c4 LW |
338 | } else { |
339 | $transmo .= " m{^\Q$header\E} && return 1;\n"; | |
340 | } | |
341 | ||
eff9c6e2 CS |
342 | print STDERR "$WHOAMI: Duplicate entry: \"$header\"\n" |
343 | if $msg{$header}; | |
4633a7c4 LW |
344 | |
345 | $msg{$header} = ''; | |
346 | } | |
347 | ||
348 | ||
349 | close POD_DIAG unless *main::DATA eq *POD_DIAG; | |
350 | ||
351 | die "No diagnostics?" unless %msg; | |
352 | ||
353 | $transmo .= " return 0;\n}\n"; | |
354 | print STDERR $transmo if $DEBUG; | |
355 | eval $transmo; | |
356 | die $@ if $@; | |
357 | $RS = "\n"; | |
358 | ### } | |
359 | ||
360 | if ($standalone) { | |
361 | if (!@ARGV and -t STDIN) { print STDERR "$0: Reading from STDIN\n" } | |
40da2db3 | 362 | while (defined ($error = <>)) { |
4633a7c4 LW |
363 | splainthis($error) || print THITHER $error; |
364 | } | |
365 | exit; | |
366 | } else { | |
367 | $old_w = 0; $oldwarn = ''; $olddie = ''; | |
368 | } | |
369 | ||
370 | sub import { | |
371 | shift; | |
372 | $old_w = $^W; | |
373 | $^W = 1; # yup, clobbered the global variable; tough, if you | |
374 | # want diags, you want diags. | |
375 | return if $SIG{__WARN__} eq \&warn_trap; | |
376 | ||
377 | for (@_) { | |
378 | ||
379 | /^-d(ebug)?$/ && do { | |
380 | $DEBUG++; | |
381 | next; | |
382 | }; | |
383 | ||
384 | /^-v(erbose)?$/ && do { | |
385 | $VERBOSE++; | |
386 | next; | |
387 | }; | |
388 | ||
389 | /^-p(retty)?$/ && do { | |
390 | print STDERR "$0: I'm afraid it's too late for prettiness.\n"; | |
391 | $PRETTY++; | |
392 | next; | |
393 | }; | |
394 | ||
395 | warn "Unknown flag: $_"; | |
396 | } | |
397 | ||
398 | $oldwarn = $SIG{__WARN__}; | |
399 | $olddie = $SIG{__DIE__}; | |
400 | $SIG{__WARN__} = \&warn_trap; | |
401 | $SIG{__DIE__} = \&death_trap; | |
402 | } | |
403 | ||
404 | sub enable { &import } | |
405 | ||
406 | sub disable { | |
407 | shift; | |
408 | $^W = $old_w; | |
409 | return unless $SIG{__WARN__} eq \&warn_trap; | |
410 | $SIG{__WARN__} = $oldwarn; | |
411 | $SIG{__DIE__} = $olddie; | |
412 | } | |
413 | ||
414 | sub warn_trap { | |
415 | my $warning = $_[0]; | |
416 | if (caller eq $WHOAMI or !splainthis($warning)) { | |
417 | print STDERR $warning; | |
418 | } | |
37120919 | 419 | &$oldwarn if defined $oldwarn and $oldwarn and $oldwarn ne \&warn_trap; |
4633a7c4 LW |
420 | }; |
421 | ||
422 | sub death_trap { | |
423 | my $exception = $_[0]; | |
55497cff | 424 | |
425 | # See if we are coming from anywhere within an eval. If so we don't | |
426 | # want to explain the exception because it's going to get caught. | |
427 | my $in_eval = 0; | |
428 | my $i = 0; | |
429 | while (1) { | |
430 | my $caller = (caller($i++))[3] or last; | |
431 | if ($caller eq '(eval)') { | |
432 | $in_eval = 1; | |
433 | last; | |
434 | } | |
435 | } | |
436 | ||
437 | splainthis($exception) unless $in_eval; | |
4633a7c4 | 438 | if (caller eq $WHOAMI) { print STDERR "INTERNAL EXCEPTION: $exception"; } |
37120919 | 439 | &$olddie if defined $olddie and $olddie and $olddie ne \&death_trap; |
55497cff | 440 | |
441 | # We don't want to unset these if we're coming from an eval because | |
442 | # then we've turned off diagnostics. (Actually what does this next | |
443 | # line do? -PSeibel) | |
444 | $SIG{__DIE__} = $SIG{__WARN__} = '' unless $in_eval; | |
6f48387a | 445 | local($Carp::CarpLevel) = 1; |
446 | confess "Uncaught exception from user code:\n\t$exception"; | |
4633a7c4 LW |
447 | # up we go; where we stop, nobody knows, but i think we die now |
448 | # but i'm deeply afraid of the &$olddie guy reraising and us getting | |
449 | # into an indirect recursion loop | |
450 | }; | |
451 | ||
452 | sub splainthis { | |
453 | local $_ = shift; | |
454 | ### &finish_compilation unless %msg; | |
455 | s/\.?\n+$//; | |
456 | my $orig = $_; | |
457 | # return unless defined; | |
458 | if ($exact_duplicate{$_}++) { | |
459 | return 1; | |
460 | } | |
461 | s/, <.*?> (?:line|chunk).*$//; | |
462 | $real = s/(.*?) at .*? (?:line|chunk) \d+.*/$1/; | |
463 | s/^\((.*)\)$/$1/; | |
464 | return 0 unless &transmo; | |
465 | $orig = shorten($orig); | |
466 | if ($old_diag{$_}) { | |
467 | autodescribe(); | |
468 | print THITHER "$orig (#$old_diag{$_})\n"; | |
469 | $wantspace = 1; | |
470 | } else { | |
471 | autodescribe(); | |
472 | $old_diag{$_} = ++$count; | |
473 | print THITHER "\n" if $wantspace; | |
474 | $wantspace = 0; | |
475 | print THITHER "$orig (#$old_diag{$_})\n"; | |
476 | if ($msg{$_}) { | |
477 | print THITHER $msg{$_}; | |
478 | } else { | |
479 | if (0 and $standalone) { | |
480 | print THITHER " **** Error #$old_diag{$_} ", | |
481 | ($real ? "is" : "appears to be"), | |
482 | " an unknown diagnostic message.\n\n"; | |
483 | } | |
484 | return 0; | |
485 | } | |
486 | } | |
487 | return 1; | |
488 | } | |
489 | ||
490 | sub autodescribe { | |
491 | if ($VERBOSE and not $count) { | |
492 | print THITHER &{$PRETTY ? \&bold : \&noop}("DESCRIPTION OF DIAGNOSTICS"), | |
493 | "\n$msg{DESCRIPTION}\n"; | |
494 | } | |
495 | } | |
496 | ||
497 | sub unescape { | |
498 | s { | |
499 | E< | |
500 | ( [A-Za-z]+ ) | |
501 | > | |
502 | } { | |
503 | do { | |
504 | exists $HTML_Escapes{$1} | |
505 | ? do { $HTML_Escapes{$1} } | |
506 | : do { | |
f02a87df | 507 | warn "Unknown escape: E<$1> in $_"; |
4633a7c4 LW |
508 | "E<$1>"; |
509 | } | |
510 | } | |
511 | }egx; | |
512 | } | |
513 | ||
514 | sub shorten { | |
515 | my $line = $_[0]; | |
774d564b | 516 | if (length($line) > 79 and index($line, "\n") == -1) { |
4633a7c4 LW |
517 | my $space_place = rindex($line, ' ', 79); |
518 | if ($space_place != -1) { | |
519 | substr($line, $space_place, 1) = "\n\t"; | |
520 | } | |
521 | } | |
522 | return $line; | |
523 | } | |
524 | ||
525 | ||
526 | # have to do this: RS isn't set until run time, but we're executing at compile time | |
527 | $RS = "\n"; | |
528 | ||
529 | 1 unless $standalone; # or it'll complain about itself | |
530 | __END__ # wish diag dbase were more accessible |