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Postings from August 2010
On Thu, Aug 5, 2010 at 12:03 AM, karl williamson <public@khwilliamson.com> wrote: > Jesse Vincent wrote: >> * If the user declares "use 5.14"[1] for the current lexical scope, then >> the modifiers previously allowed without spaces would become syntax errors. > > That doesn't make sense to me. Do you mean 'keywords' instead of > 'modifiers'? From the IRC discussion, that's what he meant. >> * If the user declares "use 5.14" for the current lexical scope, then >> they get the new regex modifiers without any crazy required syntax. >> > I'm not sure again what you mean. Using uppercase modifiers doesn't > conflict with existing syntax; there have been two flavors of that proposed, > and each has their adherents who I doubt view these as "crazy" I'll stand up and say that I think upper case and doubled modifiers are relatively "crazy" and I'd prefer to avoid them if we can find less surprising alternatives. >> * If the user doesn't declare "use 5.14", then they get the bad, old >> behavior that we all agree is a flaw, but that people are invariably >> depending on in old code. > > And do we remove the deprecation message for that? I think we should keep the deprecation without "use 5.14". Then in 5.16 we make it a syntax error and no longer require "use 5.14" for the new modifiers. > I would be comfortable with something similar to the following, since it > appears the discussion was ruling out the upper case modifiers: > > New regex modifiers are added in 5.14. Using them doesn't require a "use > 5.14". However, if their use in combination with other modifiers happens to > spell an existing keyword that keyword is assumed if and only if NOT in the > lexical scope of a "use 5.14". And, they get a deprecation message if they > don't have a space before that keyword. The implications are that all the > new modifiers in 5.14 are usable as /suffixes and as (?infixes:) but a few > suffix combinations are invalid unless there is a "use 5.14". I think it can be simpler: * Without "use 5.14", the new modifiers can only be used in (?:). Any "run-on" keyword (without a space) is valid but issues a deprecation warning. * With "use 5.14", the new modifiers may be used either in (?:) or as trailing modifiers. Any "run-on" keyword is a syntax error. * In 5.16, the new modifiers are always available and run-ons are always a syntax error. Whatever feature is added in 5.14 to enable the new behavior becomes a no-op. For clarity, I think this proposal includes the idea that using more than one mutually exclusive modifier, whether in (?:) or trailing, is a syntax error. -- DavidThread Previous | Thread Next