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1 | package diagnostics; |
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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 |
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30 | perl compiler and the perl interpeter, augmenting them with the more |
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31 | explicative and endearing descriptions found in L<perldiag>. Like the |
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32 | other pragmata, it affects the compilation phase of your program rather |
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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 |
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51 | any other diagnostics. The $diagnostics::PRETTY variable can generate nicer |
52 | escape sequences for pagers. |
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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, |
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87 | as the theoretical |
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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 |
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132 | to be honored, but only after the diagnostics::splainthis() function |
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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. |
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148 | You have to do this instead, and I<before> you load the module. |
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149 | |
150 | BEGIN { $diagnostics::PRETTY = 1 } |
151 | |
152 | I could start up faster by delaying compilation until it should be |
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153 | needed, but this gets a "panic: top_level" when using the pragma form |
154 | in Perl 5.001e. |
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155 | |
156 | While it's true that this documentation is somewhat subserious, if you use |
157 | a program named I<splain>, you should expect a bit of whimsy. |
158 | |
159 | =head1 AUTHOR |
160 | |
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161 | Tom Christiansen <F<tchrist@mox.perl.com>>, 25 June 1995. |
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162 | |
163 | =cut |
164 | |
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165 | require 5.001; |
5f05dabc |
166 | use Carp; |
167 | |
168 | use Config; |
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169 | ($privlib, $archlib) = @Config{qw(privlibexp archlibexp)}; |
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170 | if ($^O eq 'VMS') { |
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171 | require VMS::Filespec; |
172 | $privlib = VMS::Filespec::unixify($privlib); |
173 | $archlib = VMS::Filespec::unixify($archlib); |
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174 | } |
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175 | @trypod = ("$archlib/pod/perldiag.pod", |
176 | "$privlib/pod/perldiag-$].pod", |
177 | "$privlib/pod/perldiag.pod"); |
178 | ($PODFILE) = ((grep { -e } @trypod), $trypod[$#trypod])[0]; |
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179 | |
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180 | $DEBUG ||= 0; |
181 | my $WHOAMI = ref bless []; # nobody's business, prolly not even mine |
182 | |
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183 | $| = 1; |
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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; |
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195 | Getopt::Std::getopts('pdvf:') |
196 | or die "Usage: $0 [-v] [-p] [-f splainpod]"; |
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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]<(.*?)>/$1/g; |
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323 | |
324 | if ($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; |
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335 | $lhs =~ s/\.\*\?$/.*/; # Allow %s at the end to eat it all |
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336 | } |
e7ea3e70 |
337 | $transmo .= " s{^$lhs}\n {\Q$rhs\E}s\n\t&& return 1;\n"; |
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338 | } else { |
339 | $transmo .= " m{^\Q$header\E} && return 1;\n"; |
340 | } |
341 | |
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342 | print STDERR "$WHOAMI: Duplicate entry: \"$header\"\n" |
343 | if $msg{$header}; |
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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 = <>)) { |
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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 |
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$exception"; |
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447 | # up we go; where we stop, nobody knows, but i think we die now |
448 | # but i'm deeply afraid of the &$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 |
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) { |
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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 |