On Sun, Feb 23, 2020 at 05:58:30AM -0700, Matthew Flatt wrote: > > Converting loops into closed form requires more sophisticated and > general induction reasoning than is typical in a compiler. Or it needs > ad hoc pattern patching to cover a few cases --- which I have seen gcc > do, but I don't think that's very common. >
If interest here, though not really converting loops into closed form: A language I saw proposed in the 70's has a loop construct where the request to start a new interaation was done by an 'again' statement. loop i := 3 ... ... if ... then ... ... again i+1 endif endloop Of course the again could occur in positions where it was a genuine recursive call. In most situation, though, it would be recognised as a tail-recursion and be treated like a normal iteration. And yes, there could be more than one loop variable, which would tranlate into more than one function parameter. In a syntactic situation like this, it would be easier to eliminate a loop variable that was not used, because all the calls to the loop body would be explicitly present within the syntax. -- hendrik -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/20200224123118.ejrxvnnusrk6isah%40topoi.pooq.com.
