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Symbol

Section: Perl Programmers Reference Guide (3)
Updated: perl 5.004, patch 04
Index

NAME

Symbol - manipulate Perl symbols and their names

SYNOPSIS

    use Symbol;

    $sym = gensym;    open($sym, "filename");    $_ = <$sym>;    # etc.

    ungensym $sym;      # no effect

    print qualify("x"), "\n";              # "Test::x"    print qualify("x", "FOO"), "\n"        # "FOO::x"    print qualify("BAR::x"), "\n";         # "BAR::x"    print qualify("BAR::x", "FOO"), "\n";  # "BAR::x"    print qualify("STDOUT", "FOO"), "\n";  # "main::STDOUT" (global)    print qualify(\*x), "\n";              # returns \*x    print qualify(\*x, "FOO"), "\n";       # returns \*x

    use strict refs;    print { qualify_to_ref $fh } "foo!\n";    $ref = qualify_to_ref $name, $pkg;

DESCRIPTION

Symbol::gensym creates an anonymous glob and returns a referenceto it. Such a glob reference can be used as a file or directoryhandle.

For backward compatibility with older implementations that didn'tsupport anonymous globs, Symbol::ungensym is also provided.But it doesn't do anything.

Symbol::qualify turns unqualified symbol names into qualifiedvariable names (e.g. ``myvar'' -> ``MyPackage::myvar"). If it is given asecond parameter, qualify uses it as the default package;otherwise, it uses the package of its caller. Regardless, globalvariable names (e.g. ``STDOUT'', ``ENV'', ``SIG") are always qualfied with``main::''.

Qualification applies only to symbol names (strings). References areleft unchanged under the assumption that they are glob references,which are qualified by their nature.

Symbol::qualify_to_ref is just like Symbol::qualify except that itreturns a glob ref rather than a symbol name, so you can use the resulteven if use strict 'refs' is in effect.

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