On 2004-11-04 at 16:16+0100 Koen Claessen wrote: > Benjamin Franksen wrote: > > | 1) I strongly disagree with ideas to execute IO actions > | implicitly in whatever defined or undefined sequence > | before or during main for whatever reasons. > > I agree with the objections you make. Having full IO actions > as initialization actions might be a bit too much.
I agree with that too. Let me propose what I think may be a simpler (though at present the dough is barely risen, let alone baked) alternative: external "constant" modules. First, I'd like to point out that having initialisation data that changes between runs of a programme is already possible: a programme could do IO to its own loadmodule. I mention this not as a serious suggestion, but to forestall objections about changing the content of a "constant" module. The idea is simply that we should provide a mechanism of saying to a compiler "this file (of data) is a module that exports only the variable v". Given the way IO and filesystems stand at the moment, this probably means that we'd have to restrict v to be a String (or [Word8]?), but the correct solution to that would be typed IO, and it's too early to talk about that. So we tell the compilation system that file /somewhere/contains-v contains the value of the variable v::String, and that it lives in the imaginary module Home.Of.V, and when the resulting programme is loaded, so is the content of /somewhere/contains-v, and v is bound to it. OS permitting the loading of the file should only be virtual. Now IO to /somewhere/contains-v should have no effect on the value of v, but next time the programme starts it can use the new value. Jón -- Jón Fairbairn [EMAIL PROTECTED] _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
