I was asked by someone in #llvm if felix can do polymorphic recursion, and I wasn't sure if we could. There's a paper about it:
http://www.church-project.org/reports/electronic/Hal+Kfo:BUCS-TR-2004-004.pdf That has a simple example in SML: ////////////////////////////////////////////////////////////////////// let val rec id = fn x => x and sumList = fn l => if (null l) then 0 else (id (hd l)) + (sumList (id (tl l))) in sumList [1,2,3] end ////////////////////////////////////////////////////////////////////// That doesn't work. I tried to do this in felix but it errors out: ////////////////////////////////////////////////////////////////////// open List; fun id[T] (x:T): T => x; fun sumList[T] (f:T*T->T, l:list[T]) : T => match l with | Empty[T] => 0 | Cons (?h, ?t) => f (h, sumList (f, t)) endmatch ; fun add_int (x:int, y:int) => x + y; println $ sumList (the add_int, list(1,2,3)); ////////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////////// Other exn = Flx_exceptions.Free_fixpoint(_) CLIENT ERROR [bind_exe: fun_return ] return of (sumList_mh1198<1202>[<T5163>] ()): fun return type: int<2069> must have same type as return expression: <T5163> In ./foo2.flx: line 5 col 1 to line 12 col 1 4: 5: fun sumList[T] (f:T*T->T, l:list[T]) : T => 6: //let ?x = id 5 in 7: //let ?y = id $ list(1,2,3) in 8: match l with 9: | Empty[T] => 0 10: | Cons (?h, ?t) => f (h, sumList (f, t)) 11: endmatch 12: ; 13: ////////////////////////////////////////////////////////////////////// Am I doing this wrong? ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Felix-language mailing list Felix-language@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/felix-language
