On Thu, 5 Apr 2007, Hugo Ferreira wrote: > > Hello, > > I would like to use a reserved word and substitute that by a function > call. For example, the following: > > let _ = HEAP in > let h1 = HEAP in > > would become > > let __heap = new_heap () in > let h1 = new_heap () in
You shouldn't try to do this because the parser looks only one token ahead to make its decision. If you add a rule that starts from "let" (it has to), the token which enables the parser to select this rule is in position 3, so it comes too late. Camlp4 will not warn you about the conflict but fail during preprocessing because it will choose either the predefined "let" rule or yours without knowing if it's the right one. It's what I was trying to explain in that message [ocaml-developer 20]: http://groups.google.com/group/ocaml-developer/browse_frm/thread/532cfd6cc675e98b?hl=en > To do this I attempted (here I am not checking the identifier name): > > binding: [ > [ v = LIDENT ; "=" ; "HEAP" -> <:expr<$lid:v$ = new_heap ()>> ] > ] ; You build an expression, but what you need is a pair (pattern, expression). > My problem however is how to activate the rule above? I figured I need > something like: > > Pcaml.str_item : LEVEL "top" [ > [ "let"; OPT "rec"; > l = LIST1 binding SEP "and" ; "in" -> > <str_item:< declare $list:l$ end>> > ] > ]; > > But this doesn't even compile. I then concentrated on using Pcaml's > let_binding function and see If I could simply reconstruct the > structured expression but failed. I also tried: > > Pcaml.expr: LEVEL "expr1" [ > [ > "let"; l = LIST1 Pcaml.let_binding SEP "and" ; "in" -> <:expr<$l$>> > > Here I get the error: > This expression has type (MLast.patt * MLast.expr) list That's correct, it's what let_binding returns. > but is here used with type MLast.expr let-in constructs work with a list of (pattern, expression) and one expression. let p1 = e1 and p2 = e2 in e Your quotation should look like: <:expr< let $list:l$ in $e$ >> Martin -- Martin Jambon http://martin.jambon.free.fr --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "ocaml-developer" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/ocaml-developer?hl=en For other OCaml forums, see http://caml.inria.fr/resources/forums.en.html -~----------~----~----~----~------~----~------~--~---
