Zoidberg::Utils::Error(3)

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>