Ken Fox <[EMAIL PROTECTED]> wrote: > David Mitchell wrote: > > Now of course if we have the luxury of deciding that core perl 'knows' > > about complex numbers, then of the parser can be made to recognise ... > > The core doesn't need to know -- that was my point. All the core needs > is the basic constant folding rules _it_already_has_ combined with a > macro to define "i". When you "use complex" the macro would be folded > into the parser. The core doesn't need any special support (other than > decent macros... ;) Not being au fait with all RFCs atc, are there any concrete proposal for macros like this, ir is this just a hazy suggestion? > > > In summary: Perl shouldn't do interpetation of numeric literals, but > > should instead delegate it to the numeric class currently in scope. > > I agree with you. The complication is that there isn't *a* numeric class > in scope -- there are *many* numeric classes. Well, I was assuming that there would be *a* numeric class in scope - as defined be the innermost lexical 'use foo'. I assumed that Perl wouldn't be clever enough to know about all available numberic types and automatically chose the best representation; rather that it was the programmer's responsibilty via 'use' or some other syntax. > We could model numeric > classes as a tower ala Scheme in which case a constant is given to the > most fundamental class first and then the classes higher up the tower. > The core might just implement this by throwing a compile-time exception > that can be caught by the classes higher up the tower. (I think the only > real problem here is handling large precision numbers -- everything else > can be handled with macros and constant folding.) I'm not familiar with Scheme, I'm afraid.
