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Postings from December 2014
The "stringification" CPAN module provides a lexically-scoped pragma that disables stringification of references. no stringification; say "My array is " . []; this will die with Attempted to concat a reference at ... This has already been quite useful in finding all sorts of accidental bare-ref stringification bugs in various code. It intentionally avoids a complaint when refs are used as hash keys, allowing well-behaved objects to still act nicely as hash keys. Being a lexical pragma you can of course still re-enable it if you require it in some scope. However, the module is still marked as a DEVEL-only module because the implementation of it is terrible. I couldn't find a nice way to hook into ref stringification itself, so instead I had to override every "pp_*" function that might stringify a reference and wrap it in a small checking wrapper that throws an exception if it doesn't like any of the arguments, or else just passes it back down to the original op code. In fact the module doesn't even hook all of the ops this could happen in, only a few of the more common easy ones. Other ones are much harder - e.g. for pack or sprintf, you'd have to walk the format string to even work out which positional arguments are going to be used as strings. While this is a horrible implementation, it has at least served its purpose to demonstrate how useful this ability can be to find bugs in code. It would be nice though if core provided some nicer hook to let me do this. ----- In summary: I'd like a way to hook into Perl's stringification of non-overloaded references, to provide my own custom behaviour; at least to the ability of being able to veto it with an exception, or print a warning and continue. -- Paul "LeoNerd" Evans leonerd@leonerd.org.uk http://www.leonerd.org.uk/ | https://metacpan.org/author/PEVANSThread Next