NAME

Zoidberg::Utils::Error - OO error handling

SYNOPSIS

        use Zoidberg::Utils qw/:error/;
        
        sub some_command {
                error "Wrong number of arguments"
                        unless scalar(@_) == 3;
                # do stuff
        }

        # this raises an object oriented exception

DESCRIPTION

This library supplies the methods to replace die(). These methods raise an exception but passing a object containing both the error string and caller information. Thus, when the exception is caught, more subtle error messages can be produced depending on for example verbosity settings.

If the global variable $ERROR_CALLER is set in a package using this library, all errors will pretend to originate from the call-frame identified by the number of the variable. Setting $ERROR_CALLER to 1 will result in Carp like behaviour.

Although when working within the Zoidberg framework this module should be used through the Zoidberg::Utils interface, it also can be used on it's own.

EXPORT

By default error(), bug() and todo(). When using the Zoidberg::Utils interface you also get complain(), which actually belongs to Zoidberg::Utils::Output.

METHODS

Exported methods

error($error, ..)

Raises an exception which passes on \%error.

bug($error, ..)

Like error(), but with is_bug field set.

todo($error, ..)

Like error(), but with is_todo field set.

Object methods

stringify(%opts)

Returns an error string.

Known options:

format

Types 'gnu' and 'perl' are supported. The format 'perl' is the default, 'gnu' is used by zoidberg's complain() function.

PROPAGATE($file, $line)

Is automaticly called by die() when you use for example:

        use Zoidberg::Utils::Error;

        eval { error 'test' }
        die if $@; # die is called without explicit argument !

See also "die" in perlfunc.

ATTRIBUTES

The exception raised can have the folowing attributes:

string

Original error string.

scope

The global $Zoidberg::Utils::Error::Scope at the time of the exception. This is used to hide the real caller information in the gnu formatted error string with for example the name of a builtin command.

package

Calling package.

file

Source file where the exception was raised.

line

Line in source file where the exception was raised.

debug

The calling package had the global variable $DEBUG set to a non-zero value.

stack

When debug was in effect, the caller stack is traced for a number of frames equal to the value of the debug variable and put in the stack attribute.

is_bug

This exception should never happen, if it does this is considered a bug.

is_todo

This exception is raised because some feature isn't yet implemented.

propagated

Array of arrays containg information about file and line numbers where this error was propagated, see "PROPAGATE".

Overloading

When the methods are given a hash reference as one of there arguments this hash overloads the default values of %error. Thus it is possible to fake for example the calling package, or add meta data to an exception.

AUTHOR

Jaap Karssenberg || Pardus [Larus] <pardus@cpan.org>

Copyright (c) 2003 Jaap G Karssenberg. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

Zoidberg, Zoidberg::Utils, http://www.gnu.org/prep/standards_15.html#SEC15