Devel::Symdump(3) User Contributed Perl Documentation Devel::Symdump(3)
Devel::Symdump - dump symbol names or the symbol table
@packs = qw(some_package another_package);
$obj = Devel::Symdump->new(@packs); # no recursion
$obj = Devel::Symdump->rnew(@packs); # with recursion
@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);
This little package serves to access the symbol table of perl.
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 $Devel::Symdump::MAX_RECURSION limits the recursion to prevent
contention. The default value is set to 97, just low enough to survive the test suite
without a warning about deep recursion.
does not go into recursion and only analyzes the packages that are given as arguments.
packages, scalars, arrays, hashes, functions, ios
The methods packages(), scalars(), arrays(), hashes(), functions(), ios(), and (for
older perls) unknowns() each return an array of fully qualified symbols of the
specified type in all packages that are held within a Devel::Symdump object, but
without the leading "$", "@" 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 perlref "Making References" 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
As_string() and as_HTML() return a simple string/HTML representations of the object.
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() 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
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
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.
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.
Andreas Koenig <firstname.lastname@example.org> and Tom Christiansen <email@example.com>. Based on the old
dumpvar.pl by Larry Wall.
This module is
Copyright (c) 1995, 1997, 2000, 2002, 2005, 2006 Andreas Koenig "<firstname.lastname@example.org>".
All rights reserved.
This library is free software; you may use, redistribute and/or modify it under the same
terms as Perl itself.
perl v5.16.3 2013-03-24 Devel::Symdump(3)