perl-Carp-Clan

Report errors from perspective of caller of a "clan" of modules

This module is based on "'Carp.pm'" from Perl 5.005_03. It has been modified to skip all package names matching the pattern given in the "use" statement inside the "'qw()'" term (or argument list). Suppose you have a family of modules or classes named "Pack::A", "Pack::B" and so on, and each of them uses "'Carp::Clan qw(^Pack::);'" (or at least the one in which the error or warning gets raised). Thus when for example your script "tool.pl" calls module "Pack::A", and module "Pack::A" calls module "Pack::B", an exception raised in module "Pack::B" will appear to have originated in "tool.pl" where "Pack::A" was called, and not in "Pack::A" where "Pack::B" was called, as the unmodified "'Carp.pm'" would try to make you believe ':-)'. This works similarly if "Pack::B" calls "Pack::C" where the exception is raised, et cetera. In other words, this blames all errors in the "'Pack::*'" modules on the user of these modules, i.e., on you. ';-)' The skipping of a clan (or family) of packages according to a pattern describing its members is necessary in cases where these modules are not classes derived from each other (and thus when examining '@ISA' - as in the original "'Carp.pm'" module - doesn't help). The purpose and advantage of this is that a "clan" of modules can work together (and call each other) and throw exceptions at various depths down the calling hierarchy and still appear as a monolithic block (as though they were a single module) from the perspective of the caller. In case you just want to ward off all error messages from the module in which you "'use Carp::Clan'", i.e., if you want to make all error messages or warnings to appear to originate from where your module was called (this is what you usually used to "'use Carp;'" for ';-)'), instead of in your module itself (which is what you can do with a "die" or "warn" anyway), you do not need to provide a pattern, the module will automatically provide the correct one for you. I.e., just "'use Carp::Clan;'" without any arguments and call "carp" or "croak" as appropriate, and they will automatically defend your module against all blames! In other words, a pattern is only necessary if you want to make several modules (more than one) work together and appear as though they were only one.