The following module was proposed for inclusion in the Module List:
modid: Acme::Holy
DSLIP: Rdcfp
description: Test whether references are blessed.
userid: IBB (Ian Brayshaw)
chapterid: 2 (Perl_Core_Modules)
communities:
similar:
rationale:
Acme::Holy provides a single routine, holy(), which returns the
name of the package an object has been blessed into, or undef, if
its first argument is not a blessed reference.
Isn't this what ref() does already? Yes, and no. If given a blessed
reference, ref() will return the name of the package the reference
has been blessed into. However, if ref() is passed an unblessed
reference, then it will return the type of reference (e.g. SCALAR,
HASH, CODEREF, etc). This means that a call to ref() by itself
cannot determine if a given reference is an object. holy() differs
from ref() by returning undef if its first argument is not a blessed
reference (even if it is a reference).
Can't we use UNIVERSAL::isa()? Yes, and no. If you already have an
object, then isa() will let you know if it inherits from a given
class. But what do we do if we know nothing of the inheritance tree
of the object's class? Also, if we don't have an object, just a
normal reference, then attempting to call isa() through it will
result in a run-time error.
holy() is a quick, single test to determine if a given scalar
represents an object (i.e. a blessed reference).
enteredby: IBB (Ian Brayshaw)
enteredon: Mon Jun 16 02:31:03 2003 GMT
The resulting entry would be:
Acme::
::Holy Rdcfp Test whether references are blessed. IBB
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