534 lines
14 KiB
Perl
534 lines
14 KiB
Perl
package diagnostics;
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=head1 NAME
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diagnostics - Perl compiler pragma to force verbose warning diagnostics
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splain - standalone program to do the same thing
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=head1 SYNOPSIS
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As a pragma:
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use diagnostics;
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use diagnostics -verbose;
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enable diagnostics;
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disable diagnostics;
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Aa a program:
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perl program 2>diag.out
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splain [-v] [-p] diag.out
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=head1 DESCRIPTION
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=head2 The C<diagnostics> Pragma
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This module extends the terse diagnostics normally emitted by both the
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perl compiler and the perl interpeter, augmenting them with the more
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explicative and endearing descriptions found in L<perldiag>. Like the
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other pragmata, it affects the compilation phase of your program rather
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than merely the execution phase.
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To use in your program as a pragma, merely invoke
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use diagnostics;
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at the start (or near the start) of your program. (Note
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that this I<does> enable perl's B<-w> flag.) Your whole
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compilation will then be subject(ed :-) to the enhanced diagnostics.
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These still go out B<STDERR>.
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Due to the interaction between runtime and compiletime issues,
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and because it's probably not a very good idea anyway,
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you may not use C<no diagnostics> to turn them off at compiletime.
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However, you may control there behaviour at runtime using the
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disable() and enable() methods to turn them off and on respectively.
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The B<-verbose> flag first prints out the L<perldiag> introduction before
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any other diagnostics. The $diagnostics::PRETTY variable can generate nicer
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escape sequences for pagers.
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=head2 The I<splain> Program
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While apparently a whole nuther program, I<splain> is actually nothing
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more than a link to the (executable) F<diagnostics.pm> module, as well as
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a link to the F<diagnostics.pod> documentation. The B<-v> flag is like
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the C<use diagnostics -verbose> directive.
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The B<-p> flag is like the
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$diagnostics::PRETTY variable. Since you're post-processing with
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I<splain>, there's no sense in being able to enable() or disable() processing.
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Output from I<splain> is directed to B<STDOUT>, unlike the pragma.
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=head1 EXAMPLES
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The following file is certain to trigger a few errors at both
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runtime and compiletime:
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use diagnostics;
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print NOWHERE "nothing\n";
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print STDERR "\n\tThis message should be unadorned.\n";
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warn "\tThis is a user warning";
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print "\nDIAGNOSTIC TESTER: Please enter a <CR> here: ";
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my $a, $b = scalar <STDIN>;
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print "\n";
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print $x/$y;
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If you prefer to run your program first and look at its problem
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afterwards, do this:
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perl -w test.pl 2>test.out
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./splain < test.out
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Note that this is not in general possible in shells of more dubious heritage,
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as the theoretical
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(perl -w test.pl >/dev/tty) >& test.out
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./splain < test.out
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Because you just moved the existing B<stdout> to somewhere else.
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If you don't want to modify your source code, but still have on-the-fly
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warnings, do this:
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exec 3>&1; perl -w test.pl 2>&1 1>&3 3>&- | splain 1>&2 3>&-
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Nifty, eh?
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If you want to control warnings on the fly, do something like this.
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Make sure you do the C<use> first, or you won't be able to get
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at the enable() or disable() methods.
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use diagnostics; # checks entire compilation phase
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print "\ntime for 1st bogus diags: SQUAWKINGS\n";
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print BOGUS1 'nada';
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print "done with 1st bogus\n";
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disable diagnostics; # only turns off runtime warnings
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print "\ntime for 2nd bogus: (squelched)\n";
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print BOGUS2 'nada';
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print "done with 2nd bogus\n";
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enable diagnostics; # turns back on runtime warnings
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print "\ntime for 3rd bogus: SQUAWKINGS\n";
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print BOGUS3 'nada';
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print "done with 3rd bogus\n";
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disable diagnostics;
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print "\ntime for 4th bogus: (squelched)\n";
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print BOGUS4 'nada';
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print "done with 4th bogus\n";
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=head1 INTERNALS
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Diagnostic messages derive from the F<perldiag.pod> file when available at
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runtime. Otherwise, they may be embedded in the file itself when the
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splain package is built. See the F<Makefile> for details.
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If an extant $SIG{__WARN__} handler is discovered, it will continue
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to be honored, but only after the diagnostics::splainthis() function
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(the module's $SIG{__WARN__} interceptor) has had its way with your
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warnings.
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There is a $diagnostics::DEBUG variable you may set if you're desperately
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curious what sorts of things are being intercepted.
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BEGIN { $diagnostics::DEBUG = 1 }
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=head1 BUGS
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Not being able to say "no diagnostics" is annoying, but may not be
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insurmountable.
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The C<-pretty> directive is called too late to affect matters.
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You have to do this instead, and I<before> you load the module.
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BEGIN { $diagnostics::PRETTY = 1 }
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I could start up faster by delaying compilation until it should be
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needed, but this gets a "panic: top_level" when using the pragma form
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in Perl 5.001e.
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While it's true that this documentation is somewhat subserious, if you use
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a program named I<splain>, you should expect a bit of whimsy.
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=head1 AUTHOR
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Tom Christiansen <F<tchrist@mox.perl.com>>, 25 June 1995.
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=cut
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require 5.001;
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use Carp;
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use Config;
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($privlib, $archlib) = @Config{qw(privlibexp archlibexp)};
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if ($^O eq 'VMS') {
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require VMS::Filespec;
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$privlib = VMS::Filespec::unixify($privlib);
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$archlib = VMS::Filespec::unixify($archlib);
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}
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@trypod = ("$archlib/pod/perldiag.pod",
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"$privlib/pod/perldiag-$].pod",
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"$privlib/pod/perldiag.pod");
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# handy for development testing of new warnings etc
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unshift @trypod, "./pod/perldiag.pod" if -e "pod/perldiag.pod";
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($PODFILE) = ((grep { -e } @trypod), $trypod[$#trypod])[0];
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$DEBUG ||= 0;
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my $WHOAMI = ref bless []; # nobody's business, prolly not even mine
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$| = 1;
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local $_;
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CONFIG: {
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$opt_p = $opt_d = $opt_v = $opt_f = '';
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%HTML_2_Troff = %HTML_2_Latin_1 = %HTML_2_ASCII_7 = ();
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%exact_duplicate = ();
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unless (caller) {
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$standalone++;
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require Getopt::Std;
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Getopt::Std::getopts('pdvf:')
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or die "Usage: $0 [-v] [-p] [-f splainpod]";
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$PODFILE = $opt_f if $opt_f;
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$DEBUG = 2 if $opt_d;
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$VERBOSE = $opt_v;
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$PRETTY = $opt_p;
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}
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if (open(POD_DIAG, $PODFILE)) {
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warn "Happy happy podfile from real $PODFILE\n" if $DEBUG;
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last CONFIG;
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}
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if (caller) {
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INCPATH: {
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for $file ( (map { "$_/$WHOAMI.pm" } @INC), $0) {
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warn "Checking $file\n" if $DEBUG;
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if (open(POD_DIAG, $file)) {
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while (<POD_DIAG>) {
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next unless /^__END__\s*# wish diag dbase were more accessible/;
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print STDERR "podfile is $file\n" if $DEBUG;
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last INCPATH;
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}
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}
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}
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}
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} else {
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print STDERR "podfile is <DATA>\n" if $DEBUG;
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*POD_DIAG = *main::DATA;
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}
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}
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if (eof(POD_DIAG)) {
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die "couldn't find diagnostic data in $PODFILE @INC $0";
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}
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%HTML_2_Troff = (
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'amp' => '&', # ampersand
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'lt' => '<', # left chevron, less-than
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'gt' => '>', # right chevron, greater-than
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'quot' => '"', # double quote
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"Aacute" => "A\\*'", # capital A, acute accent
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# etc
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);
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%HTML_2_Latin_1 = (
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'amp' => '&', # ampersand
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'lt' => '<', # left chevron, less-than
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'gt' => '>', # right chevron, greater-than
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'quot' => '"', # double quote
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"Aacute" => "\xC1" # capital A, acute accent
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# etc
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);
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%HTML_2_ASCII_7 = (
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'amp' => '&', # ampersand
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'lt' => '<', # left chevron, less-than
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'gt' => '>', # right chevron, greater-than
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'quot' => '"', # double quote
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"Aacute" => "A" # capital A, acute accent
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# etc
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);
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*HTML_Escapes = do {
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if ($standalone) {
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$PRETTY ? \%HTML_2_Latin_1 : \%HTML_2_ASCII_7;
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} else {
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\%HTML_2_Latin_1;
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}
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};
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*THITHER = $standalone ? *STDOUT : *STDERR;
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$transmo = <<EOFUNC;
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sub transmo {
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local \$^W = 0; # recursive warnings we do NOT need!
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study;
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EOFUNC
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### sub finish_compilation { # 5.001e panic: top_level for embedded version
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print STDERR "FINISHING COMPILATION for $_\n" if $DEBUG;
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### local
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$RS = '';
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local $_;
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while (<POD_DIAG>) {
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#s/(.*)\n//;
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#$header = $1;
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unescape();
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if ($PRETTY) {
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sub noop { return $_[0] } # spensive for a noop
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sub bold { my $str =$_[0]; $str =~ s/(.)/$1\b$1/g; return $str; }
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sub italic { my $str = $_[0]; $str =~ s/(.)/_\b$1/g; return $str; }
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s/[BC]<(.*?)>/bold($1)/ges;
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s/[LIF]<(.*?)>/italic($1)/ges;
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} else {
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s/[BC]<(.*?)>/$1/gs;
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s/[LIF]<(.*?)>/$1/gs;
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}
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unless (/^=/) {
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if (defined $header) {
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if ( $header eq 'DESCRIPTION' &&
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( /Optional warnings are enabled/
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|| /Some of these messages are generic./
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) )
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{
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next;
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}
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s/^/ /gm;
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$msg{$header} .= $_;
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}
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next;
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}
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unless ( s/=item (.*)\s*\Z//) {
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if ( s/=head1\sDESCRIPTION//) {
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$msg{$header = 'DESCRIPTION'} = '';
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}
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next;
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}
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# strip formatting directives in =item line
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($header = $1) =~ s/[A-Z]<(.*?)>/$1/g;
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if ($header =~ /%[sd]/) {
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$rhs = $lhs = $header;
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#if ($lhs =~ s/(.*?)%d(?!%d)(.*)/\Q$1\E\\d+\Q$2\E\$/g) {
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if ($lhs =~ s/(.*?)%d(?!%d)(.*)/\Q$1\E\\d+\Q$2\E/g) {
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$lhs =~ s/\\%s/.*?/g;
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} else {
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# if i had lookbehind negations, i wouldn't have to do this \377 noise
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$lhs =~ s/(.*?)%s/\Q$1\E.*?\377/g;
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#$lhs =~ s/\377([^\377]*)$/\Q$1\E\$/;
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$lhs =~ s/\377([^\377]*)$/\Q$1\E/;
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$lhs =~ s/\377//g;
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$lhs =~ s/\.\*\?$/.*/; # Allow %s at the end to eat it all
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}
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$transmo .= " s{^$lhs}\n {\Q$rhs\E}s\n\t&& return 1;\n";
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} else {
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$transmo .= " m{^\Q$header\E} && return 1;\n";
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}
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print STDERR "$WHOAMI: Duplicate entry: \"$header\"\n"
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if $msg{$header};
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$msg{$header} = '';
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}
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close POD_DIAG unless *main::DATA eq *POD_DIAG;
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die "No diagnostics?" unless %msg;
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$transmo .= " return 0;\n}\n";
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print STDERR $transmo if $DEBUG;
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eval $transmo;
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die $@ if $@;
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$RS = "\n";
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### }
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if ($standalone) {
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if (!@ARGV and -t STDIN) { print STDERR "$0: Reading from STDIN\n" }
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while (defined ($error = <>)) {
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splainthis($error) || print THITHER $error;
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}
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exit;
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} else {
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$old_w = 0; $oldwarn = ''; $olddie = '';
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}
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sub import {
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shift;
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$old_w = $^W;
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$^W = 1; # yup, clobbered the global variable; tough, if you
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# want diags, you want diags.
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return if $SIG{__WARN__} eq \&warn_trap;
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for (@_) {
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/^-d(ebug)?$/ && do {
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$DEBUG++;
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next;
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};
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/^-v(erbose)?$/ && do {
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$VERBOSE++;
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next;
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};
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/^-p(retty)?$/ && do {
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print STDERR "$0: I'm afraid it's too late for prettiness.\n";
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$PRETTY++;
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next;
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};
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warn "Unknown flag: $_";
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}
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$oldwarn = $SIG{__WARN__};
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$olddie = $SIG{__DIE__};
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$SIG{__WARN__} = \&warn_trap;
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$SIG{__DIE__} = \&death_trap;
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}
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sub enable { &import }
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sub disable {
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shift;
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$^W = $old_w;
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return unless $SIG{__WARN__} eq \&warn_trap;
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$SIG{__WARN__} = $oldwarn;
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$SIG{__DIE__} = $olddie;
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}
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sub warn_trap {
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my $warning = $_[0];
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if (caller eq $WHOAMI or !splainthis($warning)) {
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print STDERR $warning;
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}
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&$oldwarn if defined $oldwarn and $oldwarn and $oldwarn ne \&warn_trap;
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};
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sub death_trap {
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my $exception = $_[0];
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# See if we are coming from anywhere within an eval. If so we don't
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# want to explain the exception because it's going to get caught.
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my $in_eval = 0;
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my $i = 0;
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while (1) {
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my $caller = (caller($i++))[3] or last;
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if ($caller eq '(eval)') {
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$in_eval = 1;
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last;
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}
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}
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splainthis($exception) unless $in_eval;
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if (caller eq $WHOAMI) { print STDERR "INTERNAL EXCEPTION: $exception"; }
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&$olddie if defined $olddie and $olddie and $olddie ne \&death_trap;
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# We don't want to unset these if we're coming from an eval because
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# then we've turned off diagnostics. (Actually what does this next
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# line do? -PSeibel)
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$SIG{__DIE__} = $SIG{__WARN__} = '' unless $in_eval;
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local($Carp::CarpLevel) = 1;
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confess "Uncaught exception from user code:\n\t$exception";
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# up we go; where we stop, nobody knows, but i think we die now
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# but i'm deeply afraid of the &$olddie guy reraising and us getting
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# into an indirect recursion loop
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};
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sub splainthis {
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local $_ = shift;
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local $\;
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### &finish_compilation unless %msg;
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s/\.?\n+$//;
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my $orig = $_;
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# return unless defined;
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if ($exact_duplicate{$_}++) {
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return 1;
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}
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s/, <.*?> (?:line|chunk).*$//;
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$real = s/(.*?) at .*? (?:line|chunk) \d+.*/$1/;
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s/^\((.*)\)$/$1/;
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return 0 unless &transmo;
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$orig = shorten($orig);
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if ($old_diag{$_}) {
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autodescribe();
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print THITHER "$orig (#$old_diag{$_})\n";
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$wantspace = 1;
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} else {
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autodescribe();
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$old_diag{$_} = ++$count;
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print THITHER "\n" if $wantspace;
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$wantspace = 0;
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print THITHER "$orig (#$old_diag{$_})\n";
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if ($msg{$_}) {
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print THITHER $msg{$_};
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} else {
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if (0 and $standalone) {
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print THITHER " **** Error #$old_diag{$_} ",
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($real ? "is" : "appears to be"),
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" an unknown diagnostic message.\n\n";
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}
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return 0;
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}
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}
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return 1;
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}
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sub autodescribe {
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if ($VERBOSE and not $count) {
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print THITHER &{$PRETTY ? \&bold : \&noop}("DESCRIPTION OF DIAGNOSTICS"),
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"\n$msg{DESCRIPTION}\n";
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}
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}
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sub unescape {
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s {
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E<
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( [A-Za-z]+ )
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>
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} {
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do {
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exists $HTML_Escapes{$1}
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? do { $HTML_Escapes{$1} }
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: do {
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warn "Unknown escape: E<$1> in $_";
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"E<$1>";
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}
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}
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}egx;
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}
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sub shorten {
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my $line = $_[0];
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if (length($line) > 79 and index($line, "\n") == -1) {
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my $space_place = rindex($line, ' ', 79);
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if ($space_place != -1) {
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substr($line, $space_place, 1) = "\n\t";
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}
|
|
}
|
|
return $line;
|
|
}
|
|
|
|
|
|
# have to do this: RS isn't set until run time, but we're executing at compile time
|
|
$RS = "\n";
|
|
|
|
1 unless $standalone; # or it'll complain about itself
|
|
__END__ # wish diag dbase were more accessible
|