Curtis "Ovid" Poe

NAME

Perl6::Caller - OO caller() interface

VERSION

Version 0.04

SYNOPSIS

 use Perl6::Caller;

 my $sub         = caller->subroutine;
 my $line_number = caller->line;
 my $is_require  = caller(3)->is_require;

EXPORT

caller

 # standard usage
 print "In ",           caller->subroutine,
       " called from ", caller->file,
       " line ",        caller->line;

 # get a caller object
 my $caller = caller;
 my $caller = caller();   # same thing

 # get a caller object for a different stack from
 my $caller = caller(2);  # two stack frames up
 print $caller->package;  # prints the package name

 # enjoy the original flavor
 my @caller = caller;     # original caller behavior
 print $caller[0],        # prints the package name

DESCRIPTION

This module is experimental. It's also alpha. Bug reports and patches welcome.

By default, this module exports the caller function. This automatically returns a new caller object. An optional argument specifies how many stack frames back to skip, just like the CORE::caller function. This lets you do things like this:

 print "In ",           caller->subroutine,
       " called from ", caller->file,
       " line ",        caller->line;

If you do not wish the caller function imported, specify an empty import list and instantiate a new Perl6::Caller object.

 use Perl6::Caller ();
 my $caller = Perl6::Caller->new;
 print $caller->line;

Note: if the results from the module seem strange, please read perldoc -s caller carefully. It has stranger behavior than you might be aware.

METHODS

The following methods are available on the caller object. They return the same values as documented in perldoc -f caller.

There are no hints and bitmask methods because those are documented as for internal use only.

  • package

  • filename

  • line

  • subroutine

  • hasargs

  • wantarray

  • evaltext

  • is_require

Note that each of these values will report correctly for when the caller object was created. For example, the following will probably print different line numbers:

 print caller->line;
 foo();
 sub foo { 
    print caller->line;
 }

However, the following will print the same line numbers:

 my $caller = Perl6::Caller->new;   # everything is relative to here
 print $caller->line;
 foo($caller);
 sub foo { 
    my $caller = shift;
    print $caller->line;
 }

CAVEATS

Most of the time, this package should just work and not interfere with anything else.

  • $hints, $bitmask

    'hints' and 'bitmask' are not available. They are documented to be for internal use only and should not be relied upon. Further, the bitmask caused strange test failures, so I opted not to include them.

  • Subclassing

    Don't.

  • Perl 6

    I'm not entirely comfortable with the namespace. The Perl 6 caller actually does considerably more, but for me to have a hope of working that in, I need proper introspection and I don't have that. Thus, I've settled for simply having a caller object.

  • *CORE::GLOBAL::caller

    I didn't implement this, though I was tempted. It turns out to be a bit tricky in spots and I'm very concerned about globally overriding behavior. I might change my mind in the future if there's enough demand.

  • Overloading

    In string context, this returns the package name. This is to support the original caller behavior.

  • List Context

    In list context, we simply default to the original behavior of CORE::caller. However, this always assumes we've called caller with an argument. Calling caller and caller(0) are identical with this module. It's difficult to avoid since the stack frame changes.

AUTHOR

Curtis "Ovid" Poe, <ovid@cpan.org>

ACKNOWLEDGEMENTS

Thanks to phaylon for helping me revisit a bad design issue with this.

BUGS

Please report any bugs or feature requests to bug-perl6-caller@rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Perl6-Caller. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

ACKNOWLEDGEMENTS

COPYRIGHT & LICENSE

Copyright 2007 Curtis "Ovid" Poe, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.




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