ocaml/camlp4/examples/lambda_quot_patt.ml

56 lines
2.3 KiB
OCaml

(****************************************************************************)
(* *)
(* OCaml *)
(* *)
(* INRIA Rocquencourt *)
(* *)
(* Copyright 2008 Institut National de Recherche en Informatique et *)
(* en Automatique. All rights reserved. This file is distributed under *)
(* the terms of the GNU Library General Public License, with the special *)
(* exception on linking described in LICENSE at the top of the OCaml *)
(* source tree. *)
(* *)
(****************************************************************************)
(* Please keep me in sync with brion.inria.fr/gallium/index.php/Lambda_calculus_quotations *)
open Camlp4.PreCast;;
module CamlSyntax = Camlp4OCamlParser.Make(Camlp4OCamlRevisedParser.Make(Syntax));;
let patt_of_string = CamlSyntax.Gram.parse_string CamlSyntax.patt_eoi;;
module LambdaGram = MakeGram(Lexer);;
let term = LambdaGram.Entry.mk "term";;
let term_eoi = LambdaGram.Entry.mk "lambda term quotation";;
Camlp4_config.antiquotations := true;;
EXTEND LambdaGram
GLOBAL: term term_eoi;
term:
[ "top"
[ "fun"; v = var; "->"; t = term -> <:patt< `Lam($v$, $t$) >> ]
| "app"
[ t1 = SELF; t2 = SELF -> <:patt< `App($t1$, $t2$) >> ]
| "simple"
[ `ANTIQUOT((""|"term"), a) -> patt_of_string _loc a
| v = var -> <:patt< `Var($v$) >>
| "("; t = term; ")" -> t ]
];
var:
[[ v = LIDENT -> <:patt< $str:v$ >>
| `ANTIQUOT((""|"var"), a) -> patt_of_string _loc a
]];
term_eoi:
[[ t = term; `EOI -> t ]];
END;;
let expand_lambda_quot_patt loc _loc_name_opt quotation_contents =
LambdaGram.parse_string term_eoi loc quotation_contents;;
(* function <:lam< fun x -> $(t|u)$ >> -> ... *)
Syntax.Quotation.add "lam" Syntax.Quotation.DynAst.patt_tag expand_lambda_quot_patt;;
Syntax.Quotation.default := "lam";;