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Postings from February 2022
After the merge of https://github.com/Perl/perl5/pull/18958, it is possible to reliably distinguish between values that started as numbers vs values that started as strings. Essentially, if the POK flag is set, the value started as a string. If the POK flag is not set and IOK or NOK is set, it started as a number. These flags can be checked in XS, or via the B module, but cannot currently be checked in pure perl. For serializers, being able to detect the original type of a value is essential, so it would help to provide functions to provide this information. For example, providing builtin::isnumber and builtin::isstring, to go along with builtin::isbool. This does potentially have a huge impact on the language as a whole. While this is needed for serializers, providing easy access to this type data will pretty much inevitably result in people using the functions within perl for things like parameter validation. The values "2" and 2 are meant to be fully interchangeable inside perl, and new code distinguishing them will break many expectations. Even with caveats, I do think this is something that the language should provide. I am uncertain on the naming of the functions. builtin::isnumber and builtin::isstring are perhaps the most obvious, but they also imply that distinguishing these types is a normal thing to do. We may want the function names to be more opinionated, implying more strongly that they are meant to be used for things like serialization, not internal type checking. That feels like a losing battle though once any function of this type is available.Thread Next