#!/usr/bin/perl
eval 'exec /usr/bin/perl -S $0 ${1+"$@"}'
if $running_under_some_shell;
=head1 NAME
diagnostics, splain - produce verbose warning diagnostics
=head1 SYNOPSIS
Using the C<diagnostics> pragma:
use diagnostics;
use diagnostics -verbose;
enable diagnostics;
disable diagnostics;
Using the C<splain> standalone filter program:
perl program 2>diag.out
splain [-v] [-p] diag.out
Using diagnostics to get stack traces from a misbehaving script:
perl -Mdiagnostics=-traceonly my_script.pl
=head1 DESCRIPTION
=head2 The C<diagnostics> Pragma
This module extends the terse diagnostics normally emitted by both the
perl compiler and the perl interpreter (from running perl with a -w
switch or C<use warnings>), augmenting them with the more
explicative and endearing descriptions found in L<perldiag>. Like the
other pragmata, it affects the 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 their 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 variable can generate nicer
escape sequences for pagers.
Warnings dispatched from perl itself (or more accurately, those that match
descriptions found in L<perldiag>) are only displayed once (no duplicate
descriptions). User code generated warnings a la warn() are unaffected,
allowing duplicate user messages to be displayed.
This module also adds a stack trace to the error message when perl dies.
This is useful for pinpointing what
caused the death. The B<-traceonly> (or
just B<-t>) flag turns off the explanations of warning messages leaving just
the stack traces. So if your script is dieing, run it again with
perl -Mdiagnostics=-traceonly my_bad_script
to see the call stack at the time of death. By supplying the B<-warntrace>
(or just B<-w>) flag, any warnings emitted will also come with a stack
trace.
=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 theoretical
(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 diagnostics::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 do 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 Perl 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<tchrist@mox.perl.com>>, 25 June 1995.
=cut
use strict;
use 5.009001;
use Carp;
$Carp::Internal{__PACKAGE__.""}++;
our $VERSION = '1.28';
our $DEBUG;
our $VERBOSE;
our $PRETTY;
our $TRACEONLY = 0;
our $WARNTRACE = 0;
use Config;
my $privlib = $Config{privlibexp};
if ($^O eq 'VMS') {
require VMS::Filespec;
$privlib = VMS::Filespec::unixify($privlib);
}
my @trypod = (
"$privlib/pod/perldiag.pod",
"$privlib/pods/perldiag.pod",
);
# handy for development testing of new warnings etc
unshift @trypod, "./pod/perldiag.pod" if -e "pod/perldiag.pod";
(my $PODFILE) = ((grep { -e } @trypod), $trypod[$#trypod])[0];
$DEBUG ||= 0;
my $WHOAMI = ref bless []; # nobody's business, prolly not even mine
local $| = 1;
local $_;
local $.;
my $standalone;
my(%HTML_2_Troff, %HTML_2_Latin_1, %HTML_2_ASCII_7);
CONFIG: {
our $opt_p = our $opt_d = our $opt_v = our $opt_f = '';
unless (caller) {
$standalone++;
require Getopt::Std;
Getopt::Std::getopts('pdvf:')
or 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 my $file ( (map { "$_/$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 $0";
}
%HTML_2_Troff = (
'amp' => '&', # ampersand
'lt' => '<', # left chevron, less-than
'gt' => '>', # right chevron, greater-than
'quot' => '"', # double quote
"Aacute" => "A\\*'", # capital A, acute accent
# etc
);
%HTML_2_Latin_1 = (
'amp' => '&', # ampersand
'lt' => '<', # left chevron, less-than
'gt' => '>', # right chevron, greater-than
'quot' => '"', # double quote
"Aacute" => "\xC1" # capital A, acute accent
# etc
);
%HTML_2_ASCII_7 = (
'amp' => '&', # ampersand
'lt' => '<', # left chevron, less-than
'gt' => '>', # right chevron, greater-than
'quot' => '"', # double quote
"Aacute" => "A" # capital A, acute accent
# etc
);
our %HTML_Escapes;
*HTML_Escapes = do {
if ($standalone) {
$PRETTY ? \%HTML_2_Latin_1 : \%HTML_2_ASCII_7;
} else {
\%HTML_2_Latin_1;
}
};
*THITHER = $standalone ? *STDOUT : *STDERR;
my %transfmt = ();
my $transmo = <<EOFUNC;
sub transmo {
#local \$^W = 0; # recursive warnings we do NOT need!
EOFUNC
my %msg;
{
print STDERR "FINISHING COMPILATION for $_\n" if $DEBUG;
local $/ = '';
local $_;
my $header;
my @headers;
my $for_item;
my $seen_body;
while (<POD_DIAG>) {
sub _split_pod_link {
$_[0] =~ '(?:([^|]*)\|)?([^/]*)(?:/("?)(.*)\3)?';
($1,$2,$4);
}
unescape();
if ($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 $str; }
s/C<<< (.*?) >>>|C<< (.*?) >>|[BC]<(.*?)>/bold($+)/ges;
s/[IF]<(.*?)>/italic($1)/ges;
s/L<(.*?)>/
my($text,$page,$sect) = _split_pod_link($1);
defined $text
? $text
: defined $sect
? italic($sect) . ' in ' . italic($page)
: italic($page)
/ges;
s/S<(.*?)>/
$1
/ges;
} else {
s/C<<< (.*?) >>>|C<< (.*?) >>|[BC]<(.*?)>/$+/gs;
s/[IF]<(.*?)>/$1/gs;
s/L<(.*?)>/
my($text,$page,$sect) = _split_pod_link($1);
defined $text
? $text
: defined $sect
? qq '"$sect" in $page'
: $page
/ges;
s/S<(.*?)>/
$1
/ges;
}
unless (/^=/) {
if (defined $header) {
if ( $header eq 'DESCRIPTION' &&
( /Optional warnings are enabled/
|| /Some of these messages are generic./
) )
{
next;
}
s/^/ /gm;
$msg{$header} .= $_;
for my $h(@headers) { $msg{$h} .= $_ }
++$seen_body;
undef $for_item;
}
next;
}
# If we have not come across the body of the description yet, then
# the previous header needs to share the same description.
if ($seen_body) {
@headers = ();
}
else {
push @headers, $header if defined $header;
}
unless ( s/=item (.*?)\s*\z//) {
if ( s/=head1\sDESCRIPTION//) {
$msg{$header = 'DESCRIPTION'} = '';
undef $for_item;
}
elsif( s/^=for\s+diagnostics\s*\n(.*?)\s*\z// ) {
$for_item = $1;
}
next;
}
if( $for_item ) { $header = $for_item; undef $for_item }
else {
$header = $1;
while( $header =~ /[;,]\z/ ) {
<POD_DIAG> =~ /^\s*(.*?)\s*\z/;
$header .= ' '.$1;
}
}
# strip formatting directives from =item line
$header =~ s/[A-Z]<(.*?)>/$1/g;
# Since we strip "\.\n" when we search a warning, strip it here as well
$header =~ s/\.?$//;
my @toks = split( /(%l?[dxX]|%u|%c|%(?:\.\d+)?[fs])/, $header );
if (@toks > 1) {
my $conlen = 0;
for my $i (0..$#toks){
if( $i % 2 ){
if( $toks[$i] eq '%c' ){
$toks[$i] = '.';
} elsif( $toks[$i] =~ /^%(?:d|u)$/ ){
$toks[$i] = '\d+';
} elsif( $toks[$i] =~ '^%(?:s|.*f)$' ){
$toks[$i] = $i == $#toks ? '.*' : '.*?';
} elsif( $toks[$i] =~ '%.(\d+)s' ){
$toks[$i] = ".{$1}";
} elsif( $toks[$i] =~ '^%l*([xX])$' ){
$toks[$i] = $1 eq 'x' ? '[\da-f]+' : '[\dA-F]+';
}
} elsif( length( $toks[$i] ) ){
$toks[$i] = quotemeta $toks[$i];
$conlen += length( $toks[$i] );
}
}
my $lhs = join( '', @toks );
$transfmt{$header}{pat} =
" s{^$lhs}\n {\Q$header\E}s\n\t&& return 1;\n";
$transfmt{$header}{len} = $conlen;
} else {
$transfmt{$header}{pat} =
" m{^\Q$header\E} && return 1;\n";
$transfmt{$header}{len} = length( $header );
}
print STDERR "$WHOAMI: Duplicate entry: \"$header\"\n"
if $msg{$header};
$msg{$header} = '';
$seen_body = 0;
}
close POD_DIAG unless *main::DATA eq *POD_DIAG;
die "No diagnostics?" unless %msg;
# Apply patterns in order of decreasing sum of lengths of fixed parts
# Seems the best way of hitting the right one.
for my $hdr ( sort { $transfmt{$b}{len} <=> $transfmt{$a}{len} }
keys %transfmt ){
$transmo .= $transfmt{$hdr}{pat};
}
$transmo .= " return 0;\n}\n";
print STDERR $transmo if $DEBUG;
eval $transmo;
die $@ if $@;
}
if ($standalone) {
if (!@ARGV and -t STDIN) { print STDERR "$0: Reading from STDIN\n" }
while (defined (my $error = <>)) {
splainthis($error) || print THITHER $error;
}
exit;
}
my $olddie;
my $oldwarn;
sub import {
shift;
$^W = 1; # yup, clobbered the global variable;
# tough, if you want diags, you want diags.
return if defined $SIG{__WARN__} && ($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";
$PRETTY++;
next;
};
# matches trace and traceonly for legacy doc mixup reasons
/^-t(race(only)?)?$/ && do {
$TRACEONLY++;
next;
};
/^-w(arntrace)?$/ && do {
$WARNTRACE++;
next;
};
warn "Unknown flag: $_";
}
$oldwarn = $SIG{__WARN__};
$olddie = $SIG{__DIE__};
$SIG{__WARN__} = \&warn_trap;
$SIG{__DIE__} = \&death_trap;
}
sub enable { &import }
sub disable {
shift;
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)) {
if ($WARNTRACE) {
print STDERR Carp::longmess($warning);
} else {
print STDERR $warning;
}
}
goto &$oldwarn if defined $oldwarn and $oldwarn and $oldwarn ne \&warn_trap;
};
sub death_trap {
my $exception = $_[0];
# See if we are coming from anywhere within an eval. If so we don't
# want to explain the exception because it's going to get caught.
my $in_eval = 0;
my $i = 0;
while (my $caller = (caller($i++))[3]) {
if ($caller eq '(eval)') {
$in_eval = 1;
last;
}
}
splainthis($exception) unless $in_eval;
if (caller eq $WHOAMI) { print STDERR "INTERNAL EXCEPTION: $exception"; }
&$olddie if defined $olddie and $olddie and $olddie ne \&death_trap;
return if $in_eval;
# We don't want to unset these if we're coming from an eval because
# then we've turned off diagnostics.
# Switch off our die/warn handlers so we don't wind up in our own
# traps.
$SIG{__DIE__} = $SIG{__WARN__} = '';
$exception =~ s/\n(?=.)/\n\t/gas;
die Carp::longmess("__diagnostics__")
=~ s/^__diagnostics__.*?line \d+\.?\n/
"Uncaught exception from user code:\n\t$exception"
/re;
# 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
};
my %exact_duplicate;
my %old_diag;
my $count;
my $wantspace;
sub splainthis {
return 0 if $TRACEONLY;
for (my $tmp = shift) {
local $\;
local $!;
### &finish_compilation unless %msg;
s/\.?\n+$//;
my $orig = $_;
# return unless defined;
# get rid of the where-are-we-in-input part
s/, <.*?> (?:line|chunk).*$//;
# Discard 1st " at <file> line <no>" and all text beyond
# but be aware of messages containing " at this-or-that"
my $real = 0;
my @secs = split( / at / );
return unless @secs;
$_ = $secs[0];
for my $i ( 1..$#secs ){
if( $secs[$i] =~ /.+? (?:line|chunk) \d+/ ){
$real = 1;
last;
} else {
$_ .= ' at ' . $secs[$i];
}
}
# remove parenthesis occurring at the end of some messages
s/^\((.*)\)$/$1/;
if ($exact_duplicate{$orig}++) {
return &transmo;
} else {
return 0 unless &transmo;
}
my $short = shorten($orig);
if ($old_diag{$_}) {
autodescribe();
print THITHER "$short (#$old_diag{$_})\n";
$wantspace = 1;
} elsif (!$msg{$_} && $orig =~ /\n./s) {
# A multiline message, like "Attempt to reload /
# Compilation failed"
my $found;
for (split /^/, $orig) {
splainthis($_) and $found = 1;
}
return $found;
} else {
autodescribe();
$old_diag{$_} = ++$count;
print THITHER "\n" if $wantspace;
$wantspace = 0;
print THITHER "$short (#$old_diag{$_})\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: E<$1> in $_";
"E<$1>";
}
}
}egx;
}
sub shorten {
my $line = $_[0];
if (length($line) > 79 and index($line, "\n") == -1) {
my $space_place = rindex($line, ' ', 79);
if ($space_place != -1) {
substr($line, $space_place, 1) = "\n\t";
}
}
return $line;
}
1 unless $standalone; # or it'll complain about itself
__END__ # wish diag dbase were more accessible
Rosenblum TV: Video training, virtual workshops, classes, tutorials
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Creating entirely new & cost-effective production methods
From the world leaders in video production training and the creators of Character Driven Storytelling™
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WHAT WE DO
Over the past 35 years, we have designed, built or restructured some of the most powerful news and journalism companies in the world.
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This is television news done the way newspaper journalism is done – one reporter with their electronic pad and pencil.
In doing this, we can cut the cost of production by as much as 75% while increasing ratings and audience engagement.
In the place of conventional TV news ‘packages’ – ie, reporter stand up, interview, b-roll, man on the street, we marry great journalism with Netflix and Hollywood storytelling.
It’s a combination that works.
We have taken most of our clients to #1 in their respective markets.
And it’s not just for news. Any company, any profit, any NGO and anyone else who is online needs to tell their story in compelling yet cost-effective video. We can teach you to do that. Either in person or virtually.
EXAMPLES OF WHAT WE CAN TEACH YOUR STAFF TO PRODUCE
ITAY HOD
Itay Hod, MMJ with KPIX/CBS in San Francisco, took the 5-Day Intensive Video Storytelling Bootcamp in 2018.
Because he works alone, with only an iPhone, he was able to embed himself with a homeless family.
Here’s the story he produced in a one-day turn.
KIET DO
Kiet Do, an MMJ with KPIX/CBS in San Francisco, took the 5-Day Intensive Video Storytelling Bootcamp in 2021.
Here is a story he produced, all on his own, with only an iPhone and in a one-day turn.
TAYLOR SCHAUB
Taylor Schaub, an MMJ with Spectrum News 1 in LA, took the 5-Day Intensive Video Storytelling Bootcamp in 2023.
Here is a story he turned in only one day, using only an iPhone. It was the first video story he ever did and it was nominated for an Emmy.
THE BOOTCAMP
How do we convert stations and whole networks to working in this way?
Since 1988, we have run intensive 5-Day Video Storytelling Bootcamps
We have done these all over the world.
These are hands-on bootcamps, and participants learn an entirely new way of creating TV news stories.
-We shoot at a 3:1 ratio or lower, so turnaround times are fast.
-We go directly from camera to timelilne and edit – no written scripts. We work in the medium of pictures and sound.
-We are entirely character-driven.
-We are driven by pictures and real events.
-We are focused almost entirely on ’the viewer experience’.
Since 1988, more than 70,000 journalists around the world have taken our bootcamps, either in person on virtualy.
We have started to work with CBS News, bringing our ideas of character-driven storytelling to one of the most successful and biggest networks in the United States. Since beginning to work with them ratings have climbed and more importantly, audience engagement is through the ceiling.
We started New York Times Television in 1990 and it was the first paper to be brought into the world of TV. It quickly became one of the most successful non-fiction production companies in the United States. The series and documentaries we produced won many awards including multiple Emmys.
We have been working with the BBC since the year 2000 helping to convert their national news network to our visual storytelling technique. Most recently we have trained teams from their sports, documentaries, and comedy divisions to make character-driven stories using only smartphones.
For the past five years we have worked with Spectrum News to introduce and train their journalists on visual, character driven storytelling using smartphones helping to create a different kind of local news for their network of 24-Hour News Stations across the United States.
In 2006, we were approached by the United Nations. Rather than rely on news outlets, it would be much easier to train the field operatives to produce their own stories. We spent two years working with the UN, training more than 100 of their staff in bootcamps in Geneva and Nairobi.
We trained 50 print reporters at the paper to shoot and tell their own stories, in conjunction with their print work. We built a TV newsroom in their existing print newsroom – you could not ask for a better set and they began to live stream their stories in conjunction with their print work.
We spent two years with McGraw Hill, training more than 150 of their staffers, making them completely video literate. McGraw/Hill media properties we transit included Business Week, Aviation Week, (what was the name of the architecture magazine), and JD Power and Associates.
In 1990, we were approached by The Voice of America, the official broadcasting agency for the United States Government. When we met with VOA, they were only a short wave radio broadcaster, but working with them, we took them into television, launching VOA-TV.
British based Oyster Yachts makes some of the finest yachts in the world. Like every other company, they had to find a way to feed the never-ending video demands of social media – sites like Instagram and TikTok. We trained the Oyster staff to tell their own stories, using only iPhones.
We were approached by SEPA, the Scottish Environmental Protection Agency because they had to continually find a way to ‘feed the media beast’. The result was that SEPA was able to tell their own stories, whenever they wanted, and at almost no additional cost.
Michael Rosenblum has been writing about the media since 1988. His work and ideas have appeared in The Guardian, The Huffington Post, Ilkeston Life and many other publications.
He has been blogging regularly for the past 35 years on this subject. Having taught media studies at Columbia University, NYU and now the University of Oxford, he is considered an expert on this subject.
Continue reading this post or look back at previous posts.
