NAME¶

Devel::Symdump - dump symbol names or the symbol table

SYNOPSIS¶

    # Constructor
    require Devel::Symdump;
    @packs = qw(some_package another_package);
    $obj = Devel::Symdump->new(@packs);        # no recursion
    $obj = Devel::Symdump->rnew(@packs);       # with recursion
    # Methods
    @array = $obj->packages;
    @array = $obj->scalars;
    @array = $obj->arrays;
    @array = $obj->hashes;
    @array = $obj->functions;
    @array = $obj->filehandles;  # deprecated, use ios instead
    @array = $obj->dirhandles;   # deprecated, use ios instead
    @array = $obj->ios;
    @array = $obj->unknowns;     # only perl version < 5.003 had some
    $string = $obj->as_string;
    $string = $obj->as_HTML;
    $string = $obj1->diff($obj2);
    $string = Devel::Symdump->isa_tree;    # or $obj->isa_tree
    $string = Devel::Symdump->inh_tree;    # or $obj->inh_tree
    # Methods with autogenerated objects
    # all of those call new(@packs) internally
    @array = Devel::Symdump->packages(@packs);
    @array = Devel::Symdump->scalars(@packs);
    @array = Devel::Symdump->arrays(@packs);
    @array = Devel::Symdump->hashes(@packs);
    @array = Devel::Symdump->functions(@packs);
    @array = Devel::Symdump->ios(@packs);
    @array = Devel::Symdump->unknowns(@packs);

DESCRIPTION¶

This little package serves to access the symbol table of perl.

"Devel::Symdump->rnew(@packages)"

returns a symbol table object for all subtrees below @packages. Nested Modules are analyzed recursively. If no package is given as argument, it defaults to "main". That means to get the whole symbol table, just do a "rnew" without arguments.

The global variable $Devel::Symdump::MAX_RECURSION limits the recursion to prevent contention. The default value is set to 97, just low enough to survive the test suite without a warning about deep recursion.

"Devel::Symdump->new(@packages)"

does not go into recursion and only analyzes the packages that are given as arguments.

packages, scalars, arrays, hashes, functions, ios

The methods packages(), scalars(), arrays(), hashes(), functions(), ios(), and (for older perls) unknowns() each return an array of fully qualified symbols of the specified type in all packages that are held within a Devel::Symdump object, but without the leading "$", "@" or "%". In a scalar context, they will return the number of such symbols. Unknown symbols are usually either formats or variables that haven't yet got a defined value.

Note that scalar symbol table entries are a special case. If a symbol table entry exists at all, presence of a scalar is currently unknowable, due to a feature of Perl described in "Making References" in perlref point 7. For example, this package will mark a scalar value $foo as present if any of @foo, %foo, &foo etc. have been declared or used.

as_string

as_HTML

As_string() and as_HTML() return a simple string/HTML representations of the object.

diff

Diff() prints the difference between two Devel::Symdump objects in human readable form. The format is similar to the one used by the as_string method.

isa_tree

inh_tree

Isa_tree() and inh_tree() both return a simple string representation of the current inheritance tree. The difference between the two methods is the direction from which the tree is viewed: top-down or bottom-up. As I'm sure, many users will have different expectation about what is top and what is bottom, I'll provide an example what happens when the Socket module is loaded:

% print Devel::Symdump->inh_tree

    AutoLoader
            DynaLoader
                    Socket
    DynaLoader
            Socket
    Exporter
            Carp
            Config
            Socket
    

The inh_tree method shows on the left hand side a package name and indented to the right the packages that use the former.

% print Devel::Symdump->isa_tree

    Carp
            Exporter
    Config
            Exporter
    DynaLoader
            AutoLoader
    Socket
            Exporter
            DynaLoader
                    AutoLoader
    

The isa_tree method displays from left to right ISA relationships, so Socket IS A DynaLoader and DynaLoader IS A AutoLoader. (Actually, they were at the time this manpage was written)

You may call both methods, isa_tree() and inh_tree(), with an object. If you do that, the object will store the output and retrieve it when you call the same method again later. The typical usage would be to use them as class methods directly though.

SUBCLASSING¶

The design of this package is intentionally primitive and allows it to be subclassed easily. An example of a (maybe) useful subclass is Devel::Symdump::Export, a package which exports all methods of the Devel::Symdump package and turns them into functions.

SEE ALSO¶

Routines for manipulating stashes: "Package::Stash"; to work with lexicals: "PadWalker".

AUTHORS¶

Andreas Koenig <andk@cpan.org> and Tom Christiansen <tchrist@perl.com>. Based on the old dumpvar.pl by Larry Wall.

COPYRIGHT, LICENSE¶

This module is

Copyright (c) 1995, 1997, 2000, 2002, 2005, 2006 Andreas Koenig "<andk@cpan.org>".

All rights reserved.

This library is free software; you may use, redistribute and/or modify it under the same terms as Perl itself.