Re: [Caml-list] Re: GenerateFold

[Joel Reymont <joelr1@gmail.com>]

Doesn't work!

On Jun 1, 2007, at 2:30 PM, Nicolas Pouillard wrote:

> Got it:
>
> There is the solution available for meditation :)

To be precise, I don't know if it works or not. I think the fold  
generator bombs out.

I have no idea how to debug this but, again, it has nothing to do  
with the implementation of is_fun_arg.

Simply using GenerateFold triggers the error. Notice that everything  
but class fold = ... is commented out. I'm including everything  
needed to reproduce the error, just in case.

ocamlbuild c.byte
+ /usr/local/bin/ocamlc.opt -c -I +camlp4 -pp 'camlp4of -I src - 
filter map -filter fold -filter trash ' -o b.cmo b.ml
File "ghost-location", line 1, characters 0-0:
This expression has type
   < array : 'b. ('a -> 'b -> 'a) -> 'b array -> 'a; bool : bool -> 'a;
     expr : A.expr -> 'a; float : float -> 'a; id : A.id -> 'a;
     input_decl : A.input_decl -> 'a; int : int -> 'a;
     list : 'c. ('a -> 'c -> 'a) -> 'c list -> 'a;
     option : 'd. ('a -> 'd -> 'a) -> 'd option -> 'a; order :  
A.order -> 'a;
     order_type : A.order_type -> 'a; program : A.program -> 'a;
     ref : 'e. ('a -> 'e -> 'a) -> 'e ref -> 'a;
     statement : A.statement -> 'a; string : string -> 'a;
     subscript : A.subscript -> 'a; ty : A.ty -> 'a; .. >
   as 'a
but is here used with type A.order_type

cat b.ml
open A

class fold = Camlp4Filters.GenerateFold.generated;;

(*
let is_fun_arg = object
inherit fold as super
val found = false
method found = found
method input_decl x =
    match x with
      | `FunArgDecl _ -> {< found = true >}
      | _             -> super#input_decl x
end

let is_fun x = (is_fun_arg#statement x)#found;;
*)

module Camlp4Trash = struct
   INCLUDE "a.ml";;
end;;

cat a.ml
type id = string

and program = statement list

and ty =
     [
     | `TyAny
     ]

and statement =
     [
     | `Skip
     | `InputDecls of input_decl list
     ]

and subscript = expr list

and input_decl =
     [
     | `InputDecl of id * ty * expr
     | `FunArgDecl of id * ty * subscript
     ]

and expr =
     [
     | `Int of int
     | `Float of float
     | `Str of string
     ]

and order = {
   order_type: order_type;
}

and order_type =
     [
     | `Buy
     | `Sell
     | `Short
     | `Cover
     ]

cat c.ml
open A
open B

cat _tags
"b.ml": use_camlp4, pp(camlp4of -I src -filter map -filter fold - 
filter trash )


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