package Carp;
-our $VERSION = '1.01';
+our $VERSION = '1.05';
+# this file is an utra-lightweight stub. The first time a function is
+# called, Carp::Heavy is loaded, and the real short/longmessmess_jmp
+# subs are installed
+
+our $MaxEvalLen = 0;
+our $Verbose = 0;
+our $CarpLevel = 0;
+our $MaxArgLen = 64; # How much of each argument to print. 0 = all.
+our $MaxArgNums = 8; # How many arguments to print. 0 = all.
+
+require Exporter;
+our @ISA = ('Exporter');
+our @EXPORT = qw(confess croak carp);
+our @EXPORT_OK = qw(cluck verbose longmess shortmess);
+our @EXPORT_FAIL = qw(verbose); # hook to enable verbose mode
+
+# if the caller specifies verbose usage ("perl -MCarp=verbose script.pl")
+# then the following method will be called by the Exporter which knows
+# to do this thanks to @EXPORT_FAIL, above. $_[1] will contain the word
+# 'verbose'.
+
+sub export_fail { shift; $Verbose = shift if $_[0] eq 'verbose'; @_ }
+
+# fixed hooks for stashes to point to
+sub longmess { goto &longmess_jmp }
+sub shortmess { goto &shortmess_jmp }
+# these two are replaced when Carp::Heavy is loaded
+sub longmess_jmp {{ local($@, $!); require Carp::Heavy} goto &longmess_jmp}
+sub shortmess_jmp {{ local($@, $!); require Carp::Heavy} goto &shortmess_jmp}
+
+sub croak { die shortmess @_ }
+sub confess { die longmess @_ }
+sub carp { warn shortmess @_ }
+sub cluck { warn longmess @_ }
+
+1;
+__END__
=head1 NAME
confess - die of errors with stack backtrace
+shortmess - return the message that carp and croak produce
+
+longmess - return the message that cluck and confess produce
+
=head1 SYNOPSIS
use Carp;
use Carp qw(cluck);
cluck "This is how we got here!";
+ print FH Carp::shortmess("This will have caller's details added");
+ print FH Carp::longmess("This will have stack backtrace added");
+
=head1 DESCRIPTION
The Carp routines are useful in your own modules because
they act like die() or warn(), but with a message which is more
likely to be useful to a user of your module. In the case of
-cluck and confess that context is a summary of every
-call in the call-stack. For a shorter message you can use carp
-or croak which try to report the error as being from where
+cluck, confess, and longmess that context is a summary of every
+call in the call-stack. For a shorter message you can use carp,
+croak or shortmess which report the error as being from where
your module was called. There is no guarantee that that is where
the error was, but it is a good educated guess.
-Here is a more complete description of how the shorter message works.
-What it does is search the call-stack for a function call stack where
+You can also alter the way the output and logic of C<Carp> works, by
+changing some global variables in the C<Carp> namespace. See the
+section on C<GLOBAL VARIABLES> below.
+
+Here is a more complete description of how shortmess works. What
+it does is search the call-stack for a function call stack where
it hasn't been told that there shouldn't be an error. If every
call is marked safe, it then gives up and gives a full stack
backtrace instead. In other words it presumes that the first likely
=item 1.
-Any call from a package to itself is safe.
+Any call from a package to itself is safe.
=item 2.
=item 5.
Any call to Carp is safe. (This rule is what keeps it from
-reporting the error where you call carp or croak.)
+reporting the error where you call carp/croak/shortmess.)
=back
or by including the string C<MCarp=verbose> in the PERL5OPT
environment variable.
+Alternately, you can set the global variable C<$Carp::Verbose> to true.
+See the C<GLOBAL VARIABLES> section below.
+
+=head1 GLOBAL VARIABLES
+
+=head2 $Carp::CarpLevel
+
+This variable determines how many call frames are to be skipped when
+reporting where an error occurred on a call to one of C<Carp>'s
+functions. For example:
+
+ $Carp::CarpLevel = 1;
+ sub bar { .... or _error('Wrong input') }
+ sub _error { Carp::carp(@_) }
+
+This would make Carp report the error as coming from C<bar>'s caller,
+rather than from C<_error>'s caller, as it normally would.
+
+Defaults to C<0>.
+
+=head2 $Carp::MaxEvalLen
+
+This variable determines how many characters of a string-eval are to
+be shown in the output. Use a value of C<0> to show all text.
+
+Defaults to C<0>.
+
+=head2 $Carp::MaxArgLen
+
+This variable determines how many characters of each argument to a
+function to print. Use a value of C<0> to show the full length of the
+argument.
+
+Defaults to C<64>.
+
+=head2 $Carp::MaxArgNums
+
+This variable determines how many arguments to each function to show.
+Use a value of C<0> to show all arguments to a function call.
+
+Defaults to C<8>.
+
+=head2 $Carp::Verbose
+
+This variable makes C<Carp> use the C<longmess> function at all times.
+This effectively means that all calls to C<carp> become C<cluck> and
+all calls to C<croak> become C<confess>.
+
+Note, this is analogous to using C<use Carp 'verbose'>.
+
+Defaults to C<0>.
+
=head1 BUGS
The Carp routines don't handle exception objects currently.
If called with a first argument that is a reference, they simply
call die() or warn(), as appropriate.
-=cut
-
-# This package is heavily used. Be small. Be fast. Be good.
-
-# Comments added by Andy Wardley <abw@kfs.org> 09-Apr-98, based on an
-# _almost_ complete understanding of the package. Corrections and
-# comments are welcome.
-
-# The members of %Internal are packages that are internal to perl.
-# Carp will not report errors from within these packages if it
-# can. The members of %CarpInternal are internal to Perl's warning
-# system. Carp will not report errors from within these packages
-# either, and will not report calls *to* these packages for carp and
-# croak. They replace $CarpLevel, which is deprecated. The
-# $Max(EvalLen|(Arg(Len|Nums)) variables are used to specify how the eval
-# text and function arguments should be formatted when printed.
-
-$CarpInternal{Carp}++;
-$CarpLevel = 0; # How many extra package levels to skip on carp.
- # How many calls to skip on confess.
- # Reconciling these notions is hard, use
- # %Internal and %CarpInternal instead.
-$MaxEvalLen = 0; # How much eval '...text...' to show. 0 = all.
-$MaxArgLen = 64; # How much of each argument to print. 0 = all.
-$MaxArgNums = 8; # How many arguments to print. 0 = all.
-$Verbose = 0; # If true then make shortmess call longmess instead
-
-require Exporter;
-@ISA = ('Exporter');
-@EXPORT = qw(confess croak carp);
-@EXPORT_OK = qw(cluck);
-
-# we handle verbose usage ("perl -MCarp=verbose script.pl") ourselves
-# and then erase all traces of this call so that Exporter doesn't
-# know that we have been here. BTW subclasses shouldn't try to
-# do anything useful with 'verbose', including have that be their
-# name...
-sub import {
- if (grep 'verbose' eq $_, @_) {
- @_ = grep 'verbose' ne $_, @_;
- $Verbose = "verbose";
- }
- goto &Exporter::import;
-}
-
-
-# longmess() crawls all the way up the stack reporting on all the function
-# calls made. The error string, $error, is originally constructed from the
-# arguments passed into longmess() via confess(), cluck() or shortmess().
-# This gets appended with the stack trace messages which are generated for
-# each function call on the stack.
-
-sub longmess {
- { local $@; require Carp::Heavy; } # XXX fix require to not clear $@?
- # Icky backwards compatibility wrapper. :-(
- my $call_pack = caller();
- if ($Internal{$call_pack} or $CarpInternal{$call_pack}) {
- return longmess_heavy(@_);
- }
- else {
- local $CarpLevel = $CarpLevel + 1;
- return longmess_heavy(@_);
- }
-}
-
-
-# shortmess() is called by carp() and croak() to skip all the way up to
-# the top-level caller's package and report the error from there. confess()
-# and cluck() generate a full stack trace so they call longmess() to
-# generate that. In verbose mode shortmess() calls longmess() so
-# you always get a stack trace
-
-sub shortmess { # Short-circuit &longmess if called via multiple packages
- { local $@; require Carp::Heavy; } # XXX fix require to not clear $@?
- # Icky backwards compatibility wrapper. :-(
- my $call_pack = caller();
- local @CARP_NOT = caller();
- shortmess_heavy(@_);
-}
-
-
-# the following four functions call longmess() or shortmess() depending on
-# whether they should generate a full stack trace (confess() and cluck())
-# or simply report the caller's package (croak() and carp()), respectively.
-# confess() and croak() die, carp() and cluck() warn.
-
-sub croak { die shortmess @_ }
-sub confess { die longmess @_ }
-sub carp { warn shortmess @_ }
-sub cluck { warn longmess @_ }
-
-1;
projects / p5sagit/p5-mst-13.2.git / blobdiff