Commit | Line | Data |
---|---|---|
4633a7c4 | 1 | package diagnostics; |
4633a7c4 LW |
2 | |
3 | =head1 NAME | |
4 | ||
5 | diagnostics - Perl compiler pragma to force verbose warning diagnostics | |
6 | ||
ae2c041d | 7 | splain - standalone program to do the same thing |
4633a7c4 LW |
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 | |
f610777f | 30 | perl compiler and the perl interpreter, 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 | ||
ae2c041d | 44 | Due to the interaction between runtime and compiletime issues, |
4633a7c4 | 45 | and because it's probably not a very good idea anyway, |
ae2c041d | 46 | you may not use C<no diagnostics> to turn them off at compiletime. |
4633a7c4 LW |
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 | 53 | |
097b73fc BB |
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 | ||
4633a7c4 LW |
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 | |
ae2c041d | 74 | runtime and compiletime: |
4633a7c4 LW |
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, | |
1fef88e7 | 92 | as the theoretical |
4633a7c4 LW |
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 | |
1fef88e7 | 137 | to be honored, but only after the diagnostics::splainthis() function |
4633a7c4 LW |
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. | |
864e1151 | 153 | You have to do this instead, and I<before> you load the module. |
4633a7c4 LW |
154 | |
155 | BEGIN { $diagnostics::PRETTY = 1 } | |
156 | ||
157 | I could start up faster by delaying compilation until it should be | |
a6006777 | 158 | needed, but this gets a "panic: top_level" when using the pragma form |
159 | in Perl 5.001e. | |
4633a7c4 LW |
160 | |
161 | While it's true that this documentation is somewhat subserious, if you use | |
162 | a program named I<splain>, you should expect a bit of whimsy. | |
163 | ||
164 | =head1 AUTHOR | |
165 | ||
352854fa | 166 | Tom Christiansen <F<tchrist@mox.perl.com>>, 25 June 1995. |
4633a7c4 LW |
167 | |
168 | =cut | |
169 | ||
5f05dabc | 170 | require 5.001; |
5f05dabc | 171 | use Carp; |
172 | ||
173 | use Config; | |
91a06757 | 174 | ($privlib, $archlib) = @Config{qw(privlibexp archlibexp)}; |
5f05dabc | 175 | if ($^O eq 'VMS') { |
91a06757 CS |
176 | require VMS::Filespec; |
177 | $privlib = VMS::Filespec::unixify($privlib); | |
178 | $archlib = VMS::Filespec::unixify($archlib); | |
5f05dabc | 179 | } |
7ec2cea4 GS |
180 | @trypod = ( |
181 | "$archlib/pod/perldiag.pod", | |
91a06757 | 182 | "$privlib/pod/perldiag-$].pod", |
5459498c | 183 | "$privlib/pod/perldiag.pod", |
7ec2cea4 GS |
184 | "$archlib/pods/perldiag.pod", |
185 | "$privlib/pods/perldiag-$].pod", | |
5459498c | 186 | "$privlib/pods/perldiag.pod", |
7ec2cea4 | 187 | ); |
fb73857a | 188 | # handy for development testing of new warnings etc |
189 | unshift @trypod, "./pod/perldiag.pod" if -e "pod/perldiag.pod"; | |
91a06757 | 190 | ($PODFILE) = ((grep { -e } @trypod), $trypod[$#trypod])[0]; |
5f05dabc | 191 | |
4633a7c4 LW |
192 | $DEBUG ||= 0; |
193 | my $WHOAMI = ref bless []; # nobody's business, prolly not even mine | |
194 | ||
6dab8668 | 195 | $| = 1; |
4633a7c4 LW |
196 | |
197 | local $_; | |
198 | ||
199 | CONFIG: { | |
200 | $opt_p = $opt_d = $opt_v = $opt_f = ''; | |
201 | %HTML_2_Troff = %HTML_2_Latin_1 = %HTML_2_ASCII_7 = (); | |
202 | %exact_duplicate = (); | |
203 | ||
204 | unless (caller) { | |
205 | $standalone++; | |
206 | require Getopt::Std; | |
91a06757 CS |
207 | Getopt::Std::getopts('pdvf:') |
208 | or die "Usage: $0 [-v] [-p] [-f splainpod]"; | |
4633a7c4 LW |
209 | $PODFILE = $opt_f if $opt_f; |
210 | $DEBUG = 2 if $opt_d; | |
211 | $VERBOSE = $opt_v; | |
212 | $PRETTY = $opt_p; | |
213 | } | |
214 | ||
215 | if (open(POD_DIAG, $PODFILE)) { | |
216 | warn "Happy happy podfile from real $PODFILE\n" if $DEBUG; | |
217 | last CONFIG; | |
218 | } | |
219 | ||
220 | if (caller) { | |
221 | INCPATH: { | |
222 | for $file ( (map { "$_/$WHOAMI.pm" } @INC), $0) { | |
223 | warn "Checking $file\n" if $DEBUG; | |
224 | if (open(POD_DIAG, $file)) { | |
225 | while (<POD_DIAG>) { | |
226 | next unless /^__END__\s*# wish diag dbase were more accessible/; | |
227 | print STDERR "podfile is $file\n" if $DEBUG; | |
228 | last INCPATH; | |
229 | } | |
230 | } | |
231 | } | |
232 | } | |
233 | } else { | |
234 | print STDERR "podfile is <DATA>\n" if $DEBUG; | |
235 | *POD_DIAG = *main::DATA; | |
236 | } | |
237 | } | |
238 | if (eof(POD_DIAG)) { | |
239 | die "couldn't find diagnostic data in $PODFILE @INC $0"; | |
240 | } | |
241 | ||
242 | ||
243 | %HTML_2_Troff = ( | |
244 | 'amp' => '&', # ampersand | |
245 | 'lt' => '<', # left chevron, less-than | |
246 | 'gt' => '>', # right chevron, greater-than | |
247 | 'quot' => '"', # double quote | |
248 | ||
249 | "Aacute" => "A\\*'", # capital A, acute accent | |
250 | # etc | |
251 | ||
252 | ); | |
253 | ||
254 | %HTML_2_Latin_1 = ( | |
255 | 'amp' => '&', # ampersand | |
256 | 'lt' => '<', # left chevron, less-than | |
257 | 'gt' => '>', # right chevron, greater-than | |
258 | 'quot' => '"', # double quote | |
259 | ||
260 | "Aacute" => "\xC1" # capital A, acute accent | |
261 | ||
262 | # etc | |
263 | ); | |
264 | ||
265 | %HTML_2_ASCII_7 = ( | |
266 | 'amp' => '&', # ampersand | |
267 | 'lt' => '<', # left chevron, less-than | |
268 | 'gt' => '>', # right chevron, greater-than | |
269 | 'quot' => '"', # double quote | |
270 | ||
271 | "Aacute" => "A" # capital A, acute accent | |
272 | # etc | |
273 | ); | |
274 | ||
275 | *HTML_Escapes = do { | |
276 | if ($standalone) { | |
277 | $PRETTY ? \%HTML_2_Latin_1 : \%HTML_2_ASCII_7; | |
278 | } else { | |
279 | \%HTML_2_Latin_1; | |
280 | } | |
281 | }; | |
282 | ||
283 | *THITHER = $standalone ? *STDOUT : *STDERR; | |
284 | ||
285 | $transmo = <<EOFUNC; | |
286 | sub transmo { | |
599cee73 | 287 | #local \$^W = 0; # recursive warnings we do NOT need! |
4633a7c4 LW |
288 | study; |
289 | EOFUNC | |
290 | ||
291 | ### sub finish_compilation { # 5.001e panic: top_level for embedded version | |
292 | print STDERR "FINISHING COMPILATION for $_\n" if $DEBUG; | |
293 | ### local | |
294 | $RS = ''; | |
295 | local $_; | |
296 | while (<POD_DIAG>) { | |
297 | #s/(.*)\n//; | |
298 | #$header = $1; | |
299 | ||
300 | unescape(); | |
301 | if ($PRETTY) { | |
302 | sub noop { return $_[0] } # spensive for a noop | |
303 | sub bold { my $str =$_[0]; $str =~ s/(.)/$1\b$1/g; return $str; } | |
304 | sub italic { my $str = $_[0]; $str =~ s/(.)/_\b$1/g; return $str; } | |
305 | s/[BC]<(.*?)>/bold($1)/ges; | |
306 | s/[LIF]<(.*?)>/italic($1)/ges; | |
307 | } else { | |
308 | s/[BC]<(.*?)>/$1/gs; | |
309 | s/[LIF]<(.*?)>/$1/gs; | |
310 | } | |
311 | unless (/^=/) { | |
312 | if (defined $header) { | |
313 | if ( $header eq 'DESCRIPTION' && | |
314 | ( /Optional warnings are enabled/ | |
315 | || /Some of these messages are generic./ | |
316 | ) ) | |
317 | { | |
318 | next; | |
319 | } | |
320 | s/^/ /gm; | |
321 | $msg{$header} .= $_; | |
322 | } | |
323 | next; | |
324 | } | |
325 | unless ( s/=item (.*)\s*\Z//) { | |
326 | ||
327 | if ( s/=head1\sDESCRIPTION//) { | |
328 | $msg{$header = 'DESCRIPTION'} = ''; | |
329 | } | |
330 | next; | |
331 | } | |
4fdae800 | 332 | |
333 | # strip formatting directives in =item line | |
334 | ($header = $1) =~ s/[A-Z]<(.*?)>/$1/g; | |
4633a7c4 LW |
335 | |
336 | if ($header =~ /%[sd]/) { | |
337 | $rhs = $lhs = $header; | |
338 | #if ($lhs =~ s/(.*?)%d(?!%d)(.*)/\Q$1\E\\d+\Q$2\E\$/g) { | |
339 | if ($lhs =~ s/(.*?)%d(?!%d)(.*)/\Q$1\E\\d+\Q$2\E/g) { | |
340 | $lhs =~ s/\\%s/.*?/g; | |
341 | } else { | |
342 | # if i had lookbehind negations, i wouldn't have to do this \377 noise | |
343 | $lhs =~ s/(.*?)%s/\Q$1\E.*?\377/g; | |
344 | #$lhs =~ s/\377([^\377]*)$/\Q$1\E\$/; | |
345 | $lhs =~ s/\377([^\377]*)$/\Q$1\E/; | |
346 | $lhs =~ s/\377//g; | |
e7ea3e70 | 347 | $lhs =~ s/\.\*\?$/.*/; # Allow %s at the end to eat it all |
4633a7c4 | 348 | } |
e7ea3e70 | 349 | $transmo .= " s{^$lhs}\n {\Q$rhs\E}s\n\t&& return 1;\n"; |
4633a7c4 LW |
350 | } else { |
351 | $transmo .= " m{^\Q$header\E} && return 1;\n"; | |
352 | } | |
353 | ||
eff9c6e2 CS |
354 | print STDERR "$WHOAMI: Duplicate entry: \"$header\"\n" |
355 | if $msg{$header}; | |
4633a7c4 LW |
356 | |
357 | $msg{$header} = ''; | |
358 | } | |
359 | ||
360 | ||
361 | close POD_DIAG unless *main::DATA eq *POD_DIAG; | |
362 | ||
363 | die "No diagnostics?" unless %msg; | |
364 | ||
365 | $transmo .= " return 0;\n}\n"; | |
366 | print STDERR $transmo if $DEBUG; | |
367 | eval $transmo; | |
368 | die $@ if $@; | |
369 | $RS = "\n"; | |
370 | ### } | |
371 | ||
372 | if ($standalone) { | |
373 | if (!@ARGV and -t STDIN) { print STDERR "$0: Reading from STDIN\n" } | |
40da2db3 | 374 | while (defined ($error = <>)) { |
4633a7c4 LW |
375 | splainthis($error) || print THITHER $error; |
376 | } | |
377 | exit; | |
378 | } else { | |
379 | $old_w = 0; $oldwarn = ''; $olddie = ''; | |
380 | } | |
381 | ||
382 | sub import { | |
383 | shift; | |
599cee73 | 384 | #$old_w = $^W; |
4633a7c4 LW |
385 | $^W = 1; # yup, clobbered the global variable; tough, if you |
386 | # want diags, you want diags. | |
387 | return if $SIG{__WARN__} eq \&warn_trap; | |
388 | ||
389 | for (@_) { | |
390 | ||
391 | /^-d(ebug)?$/ && do { | |
392 | $DEBUG++; | |
393 | next; | |
394 | }; | |
395 | ||
396 | /^-v(erbose)?$/ && do { | |
397 | $VERBOSE++; | |
398 | next; | |
399 | }; | |
400 | ||
401 | /^-p(retty)?$/ && do { | |
402 | print STDERR "$0: I'm afraid it's too late for prettiness.\n"; | |
403 | $PRETTY++; | |
404 | next; | |
405 | }; | |
406 | ||
407 | warn "Unknown flag: $_"; | |
408 | } | |
409 | ||
410 | $oldwarn = $SIG{__WARN__}; | |
411 | $olddie = $SIG{__DIE__}; | |
412 | $SIG{__WARN__} = \&warn_trap; | |
413 | $SIG{__DIE__} = \&death_trap; | |
414 | } | |
415 | ||
416 | sub enable { &import } | |
417 | ||
418 | sub disable { | |
419 | shift; | |
599cee73 | 420 | #$^W = $old_w; |
4633a7c4 LW |
421 | return unless $SIG{__WARN__} eq \&warn_trap; |
422 | $SIG{__WARN__} = $oldwarn; | |
423 | $SIG{__DIE__} = $olddie; | |
424 | } | |
425 | ||
426 | sub warn_trap { | |
427 | my $warning = $_[0]; | |
428 | if (caller eq $WHOAMI or !splainthis($warning)) { | |
429 | print STDERR $warning; | |
430 | } | |
37120919 | 431 | &$oldwarn if defined $oldwarn and $oldwarn and $oldwarn ne \&warn_trap; |
4633a7c4 LW |
432 | }; |
433 | ||
434 | sub death_trap { | |
435 | my $exception = $_[0]; | |
55497cff | 436 | |
437 | # See if we are coming from anywhere within an eval. If so we don't | |
438 | # want to explain the exception because it's going to get caught. | |
439 | my $in_eval = 0; | |
440 | my $i = 0; | |
441 | while (1) { | |
442 | my $caller = (caller($i++))[3] or last; | |
443 | if ($caller eq '(eval)') { | |
444 | $in_eval = 1; | |
445 | last; | |
446 | } | |
447 | } | |
448 | ||
449 | splainthis($exception) unless $in_eval; | |
4633a7c4 | 450 | if (caller eq $WHOAMI) { print STDERR "INTERNAL EXCEPTION: $exception"; } |
37120919 | 451 | &$olddie if defined $olddie and $olddie and $olddie ne \&death_trap; |
55497cff | 452 | |
453 | # We don't want to unset these if we're coming from an eval because | |
454 | # then we've turned off diagnostics. (Actually what does this next | |
455 | # line do? -PSeibel) | |
456 | $SIG{__DIE__} = $SIG{__WARN__} = '' unless $in_eval; | |
6f48387a | 457 | local($Carp::CarpLevel) = 1; |
458 | confess "Uncaught exception from user code:\n\t$exception"; | |
4633a7c4 LW |
459 | # up we go; where we stop, nobody knows, but i think we die now |
460 | # but i'm deeply afraid of the &$olddie guy reraising and us getting | |
461 | # into an indirect recursion loop | |
462 | }; | |
463 | ||
464 | sub splainthis { | |
465 | local $_ = shift; | |
5025c45a | 466 | local $\; |
4633a7c4 LW |
467 | ### &finish_compilation unless %msg; |
468 | s/\.?\n+$//; | |
469 | my $orig = $_; | |
470 | # return unless defined; | |
4633a7c4 LW |
471 | s/, <.*?> (?:line|chunk).*$//; |
472 | $real = s/(.*?) at .*? (?:line|chunk) \d+.*/$1/; | |
473 | s/^\((.*)\)$/$1/; | |
097b73fc BB |
474 | if ($exact_duplicate{$orig}++) { |
475 | return &transmo; | |
476 | } | |
477 | else { | |
478 | return 0 unless &transmo; | |
479 | } | |
4633a7c4 LW |
480 | $orig = shorten($orig); |
481 | if ($old_diag{$_}) { | |
482 | autodescribe(); | |
483 | print THITHER "$orig (#$old_diag{$_})\n"; | |
484 | $wantspace = 1; | |
485 | } else { | |
486 | autodescribe(); | |
487 | $old_diag{$_} = ++$count; | |
488 | print THITHER "\n" if $wantspace; | |
489 | $wantspace = 0; | |
490 | print THITHER "$orig (#$old_diag{$_})\n"; | |
491 | if ($msg{$_}) { | |
492 | print THITHER $msg{$_}; | |
493 | } else { | |
494 | if (0 and $standalone) { | |
495 | print THITHER " **** Error #$old_diag{$_} ", | |
496 | ($real ? "is" : "appears to be"), | |
497 | " an unknown diagnostic message.\n\n"; | |
498 | } | |
499 | return 0; | |
500 | } | |
501 | } | |
502 | return 1; | |
503 | } | |
504 | ||
505 | sub autodescribe { | |
506 | if ($VERBOSE and not $count) { | |
507 | print THITHER &{$PRETTY ? \&bold : \&noop}("DESCRIPTION OF DIAGNOSTICS"), | |
508 | "\n$msg{DESCRIPTION}\n"; | |
509 | } | |
510 | } | |
511 | ||
512 | sub unescape { | |
513 | s { | |
514 | E< | |
515 | ( [A-Za-z]+ ) | |
516 | > | |
517 | } { | |
518 | do { | |
519 | exists $HTML_Escapes{$1} | |
520 | ? do { $HTML_Escapes{$1} } | |
521 | : do { | |
f02a87df | 522 | warn "Unknown escape: E<$1> in $_"; |
4633a7c4 LW |
523 | "E<$1>"; |
524 | } | |
525 | } | |
526 | }egx; | |
527 | } | |
528 | ||
529 | sub shorten { | |
530 | my $line = $_[0]; | |
774d564b | 531 | if (length($line) > 79 and index($line, "\n") == -1) { |
4633a7c4 LW |
532 | my $space_place = rindex($line, ' ', 79); |
533 | if ($space_place != -1) { | |
534 | substr($line, $space_place, 1) = "\n\t"; | |
535 | } | |
536 | } | |
537 | return $line; | |
538 | } | |
539 | ||
540 | ||
ae2c041d | 541 | # have to do this: RS isn't set until run time, but we're executing at compiletime |
4633a7c4 LW |
542 | $RS = "\n"; |
543 | ||
544 | 1 unless $standalone; # or it'll complain about itself | |
545 | __END__ # wish diag dbase were more accessible |