On Wed, Nov 30, 2005 at 11:00:36AM -0800, Chip Salzenberg wrote: > On Wed, Nov 30, 2005 at 12:18:40PM +0100, Leopold Toetsch wrote: > > Parrot didn't throw exceptions on param or result count mismatch > > until now, and still doesn't. [1] > > [1] all PGE and PGE-based stuff is failing, when both are turned on > ... > Allowing too few parameters is already possible through the extensive > use of :optional. As for the too-many case: If we add a :last flag > which means "any additional incoming values should be ignored", then > that's covered too. Then users can avoid throwing exceptions in all > cases, if that's what they want. > > Patrick, would that work for you? For that matter, did you know that > your code dies when parameter counts are enforced?
Yes, I knew that some code pieces would have trouble when parameter counts were enforced, but I figured I'd cross that bridge when we came to it. I guess we're there now. Short answer: something like a ":last" flag would be excellent. Longer answer: In PGE, each rule is a parrot sub, and some rules can be parameterized by various parameters, which means that the number of arguments to a rule can vary depending on the rule and the context in which it can be called. So, there's not a hard-and-fast parameter list that is going to work in all situations and provide the flexibility we'll want. Thus, we really ought to have a way to indicate that a rule (parrot sub) can still be safely run even if called with more parameters than it expects. In the meantime, I'll go ahead and see about updating PGE so that any extra params from callers don't cause much grief. Pm
