diff options
Diffstat (limited to 'lib/splain')
| -rwxr-xr-x | lib/splain | 502 |
1 files changed, 502 insertions, 0 deletions
diff --git a/lib/splain b/lib/splain new file mode 100755 index 0000000000..073a456c81 --- /dev/null +++ b/lib/splain @@ -0,0 +1,502 @@ +#!/usr/local/bin/perl +eval 'exec perl -S $0 ${1+"$@"}' + if $0; + +use Config; +$diagnostics::PODFILE= $Config{privlib} . "/pod/perldiag.pod"; + +package diagnostics; +require 5.001; +use English; +use Carp; + +=head1 NAME + +diagnostics - Perl compiler pragma to force verbose warning diagnostics + +splain - standalone program to do the same thing + +=head1 SYNOPSIS + +As a pragma: + + use diagnostics; + use diagnostics -verbose; + + enable diagnostics; + disable diagnostics; + +Aa a program: + + perl program 2>diag.out + splain [-v] [-p] diag.out + + +=head1 DESCRIPTION + +=head2 The C<diagnostics> Pragma + +This module extends the terse diagnostics normally emitted by both the +perl compiler and the perl interpeter, augmenting them wtih the more +explicative and endearing descriptions found in L<perldiag>. Like the +other pragmata, it affects to compilation phase of your program rather +than merely the execution phase. + +To use in your program as a pragma, merely invoke + + use diagnostics; + +at the start (or near the start) of your program. (Note +that this I<does> enable perl's B<-w> flag.) Your whole +compilation will then be subject(ed :-) to the enhanced diagnostics. +These still go out B<STDERR>. + +Due to the interaction between runtime and compiletime issues, +and because it's probably not a very good idea anyway, +you may not use C<no diagnostics> to turn them off at compiletime. +However, you may control there behaviour at runtime using the +disable() and enable() methods to turn them off and on respectively. + +The B<-verbose> flag first prints out the L<perldiag> introduction before +any other diagnostics. The $diagnostics::PRETTY can generate nicer escape +sequences for pgers. + +=head2 The I<splain> Program + +While apparently a whole nuther program, I<splain> is actually nothing +more than a link to the (executable) F<diagnostics.pm> module, as well as +a link to the F<diagnostics.pod> documentation. The B<-v> flag is like +the C<use diagnostics -verbose> directive. +The B<-p> flag is like the +$diagnostics::PRETTY variable. Since you're post-processing with +I<splain>, there's no sense in being able to enable() or disable() processing. + +Output from I<splain> is directed to B<STDOUT>, unlike the pragma. + +=head1 EXAMPLES + +The following file is certain to trigger a few errors at both +runtime and compiletime: + + use diagnostics; + print NOWHERE "nothing\n"; + print STDERR "\n\tThis message should be unadorned.\n"; + warn "\tThis is a user warning"; + print "\nDIAGNOSTIC TESTER: Please enter a <CR> here: "; + my $a, $b = scalar <STDIN>; + print "\n"; + print $x/$y; + +If you prefer to run your program first and look at its problem +afterwards, do this: + + perl -w test.pl 2>test.out + ./splain < test.out + +Note that this is not in general possible in shells of more dubious heritage, +as the theorectical + + (perl -w test.pl >/dev/tty) >& test.out + ./splain < test.out + +Because you just moved the existing B<stdout> to somewhere else. + +If you don't want to modify your source code, but still have on-the-fly +warnings, do this: + + exec 3>&1; perl -w test.pl 2>&1 1>&3 3>&- | splain 1>&2 3>&- + +Nifty, eh? + +If you want to control warnings on the fly, do something like this. +Make sure you do the C<use> first, or you won't be able to get +at the enable() or disable() methods. + + use diagnostics; # checks entire compilation phase + print "\ntime for 1st bogus diags: SQUAWKINGS\n"; + print BOGUS1 'nada'; + print "done with 1st bogus\n"; + + disable diagnostics; # only turns off runtime warnings + print "\ntime for 2nd bogus: (squelched)\n"; + print BOGUS2 'nada'; + print "done with 2nd bogus\n"; + + enable diagnostics; # turns back on runtime warnings + print "\ntime for 3rd bogus: SQUAWKINGS\n"; + print BOGUS3 'nada'; + print "done with 3rd bogus\n"; + + disable diagnostics; + print "\ntime for 4th bogus: (squelched)\n"; + print BOGUS4 'nada'; + print "done with 4th bogus\n"; + +=head1 INTERNALS + +Diagnostic messages derive from the F<perldiag.pod> file when available at +runtime. Otherwise, they may be embedded in the file itself when the +splain package is built. See the F<Makefile> for details. + +If an extant $SIG{__WARN__} handler is discovered, it will continue +to be honored, but only after the diagnostic::splainthis() function +(the module's $SIG{__WARN__} interceptor) has had its way with your +warnings. + +There is a $diagnostics::DEBUG variable you may set if you're desperately +curious what sorts of things are being intercepted. + + BEGIN { $diagnostics::DEBUG = 1 } + + +=head1 BUGS + +Not being able to say "no diagnostics" is annoying, but may not be +insurmountable. + +The C<-pretty> directive is called too late to affect matters. +You have to to this instead, and I<before> you load the module. + + BEGIN { $diagnostics::PRETTY = 1 } + +I could start up faster by delaying compilation until it should be +needed, but this gets a "panic: top_level" +when using the pragma form in 5.001e. + +While it's true that this documentation is somewhat subserious, if you use +a program named I<splain>, you should expect a bit of whimsy. + +=head1 AUTHOR + +Tom Christiansen F<E<lt>tchrist@mox.perl.comE<gt>>, 25 June 1995. + +=cut + +$DEBUG ||= 0; +my $WHOAMI = ref bless []; # nobody's business, prolly not even mine + +$OUTPUT_AUTOFLUSH = 1; + +local $_; + +CONFIG: { + $opt_p = $opt_d = $opt_v = $opt_f = ''; + %HTML_2_Troff = %HTML_2_Latin_1 = %HTML_2_ASCII_7 = (); + %exact_duplicate = (); + + unless (caller) { + $standalone++; + require Getopt::Std; + Getopt::Std::getopts('pdvf:') || die "Usage: $0 [-v] [-p] [-f splainpod]"; + $PODFILE = $opt_f if $opt_f; + $DEBUG = 2 if $opt_d; + $VERBOSE = $opt_v; + $PRETTY = $opt_p; + } + + if (open(POD_DIAG, $PODFILE)) { + warn "Happy happy podfile from real $PODFILE\n" if $DEBUG; + last CONFIG; + } + + if (caller) { + INCPATH: { + for $file ( (map { "$_/$WHOAMI.pm" } @INC), $0) { + warn "Checking $file\n" if $DEBUG; + if (open(POD_DIAG, $file)) { + while (<POD_DIAG>) { + next unless /^__END__\s*# wish diag dbase were more accessible/; + print STDERR "podfile is $file\n" if $DEBUG; + last INCPATH; + } + } + } + } + } else { + print STDERR "podfile is <DATA>\n" if $DEBUG; + *POD_DIAG = *main::DATA; + } +} +if (eof(POD_DIAG)) { + die "couldn't find diagnostic data in $PODFILE @INC $0"; +} + + +%HTML_2_Troff = ( + 'amp' => '&', # ampersand + 'lt' => '<', # left chevron, less-than + 'gt' => '>', # right chevron, greater-than + 'quot' => '"', # double quote + + "Aacute" => "A\\*'", # capital A, acute accent + # etc + +); + +%HTML_2_Latin_1 = ( + 'amp' => '&', # ampersand + 'lt' => '<', # left chevron, less-than + 'gt' => '>', # right chevron, greater-than + 'quot' => '"', # double quote + + "Aacute" => "\xC1" # capital A, acute accent + + # etc +); + +%HTML_2_ASCII_7 = ( + 'amp' => '&', # ampersand + 'lt' => '<', # left chevron, less-than + 'gt' => '>', # right chevron, greater-than + 'quot' => '"', # double quote + + "Aacute" => "A" # capital A, acute accent + # etc +); + +*HTML_Escapes = do { + if ($standalone) { + $PRETTY ? \%HTML_2_Latin_1 : \%HTML_2_ASCII_7; + } else { + \%HTML_2_Latin_1; + } +}; + +*THITHER = $standalone ? *STDOUT : *STDERR; + +$transmo = <<EOFUNC; +sub transmo { + local \$^W = 0; # recursive warnings we do NOT need! + study; +EOFUNC + +### sub finish_compilation { # 5.001e panic: top_level for embedded version + print STDERR "FINISHING COMPILATION for $_\n" if $DEBUG; + ### local + $RS = ''; + local $_; + while (<POD_DIAG>) { + #s/(.*)\n//; + #$header = $1; + + unescape(); + if ($PRETTY) { + sub noop { return $_[0] } # spensive for a noop + sub bold { my $str =$_[0]; $str =~ s/(.)/$1\b$1/g; return $str; } + sub italic { my $str = $_[0]; $str =~ s/(.)/_\b$1/g; return $str; } + s/[BC]<(.*?)>/bold($1)/ges; + s/[LIF]<(.*?)>/italic($1)/ges; + } else { + s/[BC]<(.*?)>/$1/gs; + s/[LIF]<(.*?)>/$1/gs; + } + unless (/^=/) { + if (defined $header) { + if ( $header eq 'DESCRIPTION' && + ( /Optional warnings are enabled/ + || /Some of these messages are generic./ + ) ) + { + next; + } + s/^/ /gm; + $msg{$header} .= $_; + } + next; + } + unless ( s/=item (.*)\s*\Z//) { + + if ( s/=head1\sDESCRIPTION//) { + $msg{$header = 'DESCRIPTION'} = ''; + } + next; + } + $header = $1; + + if ($header =~ /%[sd]/) { + $rhs = $lhs = $header; + #if ($lhs =~ s/(.*?)%d(?!%d)(.*)/\Q$1\E\\d+\Q$2\E\$/g) { + if ($lhs =~ s/(.*?)%d(?!%d)(.*)/\Q$1\E\\d+\Q$2\E/g) { + $lhs =~ s/\\%s/.*?/g; + } else { + # if i had lookbehind negations, i wouldn't have to do this \377 noise + $lhs =~ s/(.*?)%s/\Q$1\E.*?\377/g; + #$lhs =~ s/\377([^\377]*)$/\Q$1\E\$/; + $lhs =~ s/\377([^\377]*)$/\Q$1\E/; + $lhs =~ s/\377//g; + } + $transmo .= " s{^$lhs}\n {\Q$rhs\E}\n\t&& return 1;\n"; + } else { + $transmo .= " m{^\Q$header\E} && return 1;\n"; + } + + print STDERR "Already saw $header" if $msg{$header}; + + $msg{$header} = ''; + } + + + close POD_DIAG unless *main::DATA eq *POD_DIAG; + + die "No diagnostics?" unless %msg; + + $transmo .= " return 0;\n}\n"; + print STDERR $transmo if $DEBUG; + eval $transmo; + die $@ if $@; + $RS = "\n"; +### } + +if ($standalone) { + if (!@ARGV and -t STDIN) { print STDERR "$0: Reading from STDIN\n" } + while ($error = <>) { + splainthis($error) || print THITHER $error; + } + exit; +} else { + $old_w = 0; $oldwarn = ''; $olddie = ''; +} + +sub import { + shift; + $old_w = $^W; + $^W = 1; # yup, clobbered the global variable; tough, if you + # want diags, you want diags. + return if $SIG{__WARN__} eq \&warn_trap; + + for (@_) { + + /^-d(ebug)?$/ && do { + $DEBUG++; + next; + }; + + /^-v(erbose)?$/ && do { + $VERBOSE++; + next; + }; + + /^-p(retty)?$/ && do { + print STDERR "$0: I'm afraid it's too late for prettiness.\n"; + $PRETTY++; + next; + }; + + warn "Unknown flag: $_"; + } + + $oldwarn = $SIG{__WARN__}; + $olddie = $SIG{__DIE__}; + $SIG{__WARN__} = \&warn_trap; + $SIG{__DIE__} = \&death_trap; +} + +sub enable { &import } + +sub disable { + shift; + $^W = $old_w; + return unless $SIG{__WARN__} eq \&warn_trap; + $SIG{__WARN__} = $oldwarn; + $SIG{__DIE__} = $olddie; +} + +sub warn_trap { + my $warning = $_[0]; + if (caller eq $WHOAMI or !splainthis($warning)) { + print STDERR $warning; + } + &$oldwarn if $oldwarn and $oldwarn ne \&warn_trap; +}; + +sub death_trap { + my $exception = $_[0]; + splainthis($exception); + if (caller eq $WHOAMI) { print STDERR "INTERNAL EXCEPTION: $exception"; } + &$olddie if defined $olddie and $olddie ne \&death_trap; + $SIG{__DIE__} = $SIG{__WARN__} = ''; + confess "Uncaught exception from user code:\n\t$exception Bailing out"; + # up we go; where we stop, nobody knows, but i think we die now + # but i'm deeply afraid of the &$olddie guy reraising and us getting + # into an indirect recursion loop +}; + +sub splainthis { + local $_ = shift; + ### &finish_compilation unless %msg; + s/\.?\n+$//; + my $orig = $_; + # return unless defined; + if ($exact_duplicate{$_}++) { + return 1; + } + s/, <.*?> (?:line|chunk).*$//; + $real = s/(.*?) at .*? (?:line|chunk) \d+.*/$1/; + s/^\((.*)\)$/$1/; + return 0 unless &transmo; + $orig = shorten($orig); + if ($old_diag{$_}) { + autodescribe(); + print THITHER "$orig (#$old_diag{$_})\n"; + $wantspace = 1; + } else { + autodescribe(); + $old_diag{$_} = ++$count; + print THITHER "\n" if $wantspace; + $wantspace = 0; + print THITHER "$orig (#$old_diag{$_})\n"; + if ($msg{$_}) { + print THITHER $msg{$_}; + } else { + if (0 and $standalone) { + print THITHER " **** Error #$old_diag{$_} ", + ($real ? "is" : "appears to be"), + " an unknown diagnostic message.\n\n"; + } + return 0; + } + } + return 1; +} + +sub autodescribe { + if ($VERBOSE and not $count) { + print THITHER &{$PRETTY ? \&bold : \&noop}("DESCRIPTION OF DIAGNOSTICS"), + "\n$msg{DESCRIPTION}\n"; + } +} + +sub unescape { + s { + E< + ( [A-Za-z]+ ) + > + } { + do { + exists $HTML_Escapes{$1} + ? do { $HTML_Escapes{$1} } + : do { + warn "Unknown escape: $& in $_"; + "E<$1>"; + } + } + }egx; +} + +sub shorten { + my $line = $_[0]; + if (length $line > 79) { + my $space_place = rindex($line, ' ', 79); + if ($space_place != -1) { + substr($line, $space_place, 1) = "\n\t"; + } + } + 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 |