There's a fun problem with fold: I tried to do this: fold_left join of (string * string) "" dirlist
and it failed .. I had this: fun join(x:string, y:string)=>x + "/" + y; but actually fold requires this: fun join(x:string) (y:string)=> x + "/" + y; The *problem* here is that the signature is now join of (string) which isn't a convenient binary operator ... also, there's a good chance there are several binary operators with the first component, and if we curry them then there's no way to identify the functions (since the second argument is actually part of the return type). During overload resolution when the function is applied, the algorithm can pick the right function based on the return type which is actually join: string -> (string -> string) The bottom line is .. it might be useful to have a version of fold that uses a product, since that's the preferred form in Felix (unlike Ocaml). The *problem* is that it would be confusing to overload these two folds.. and may lead to an ambiguity .. so any new fold would have to have a distinct name I think.. ;( -- john skaller skal...@users.sourceforge.net ------------------------------------------------------------------------------ Virtualization is moving to the mainstream and overtaking non-virtualized environment for deploying applications. Does it make network security easier or more difficult to achieve? Read this whitepaper to separate the two and get a better understanding. http://p.sf.net/sfu/hp-phase2-d2d _______________________________________________ Felix-language mailing list Felix-language@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/felix-language
