From Gallium
$ cat lambda_quot_o.ml
(* Please keep me in sync with the CVS: camlp4/examples/lambda_quot_o.ml *)
open Camlp4.PreCast;;
module CamlSyntax = Camlp4OCamlParser.Make(Camlp4OCamlRevisedParser.Make(Syntax));;
let expr_of_string = CamlSyntax.Gram.parse_string CamlSyntax.expr_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 -> <:expr< `Lam($v$, $t$) >> ]
| "app"
[ t1 = SELF; t2 = SELF -> <:expr< `App($t1$, $t2$) >> ]
| "simple"
[ `ANTIQUOT((""|"term"), a) -> expr_of_string _loc a
| v = var -> <:expr< `Var($v$) >>
| "("; t = term; ")" -> t ]
];
var:
[[ v = LIDENT -> <:expr< $str:v$ >>
| `ANTIQUOT((""|"var"), a) -> expr_of_string _loc a
]];
term_eoi:
[[ t = term; `EOI -> t ]];
END;;
let expand_lambda_quot_expr loc _loc_name_opt quotation_contents =
LambdaGram.parse_string term_eoi loc quotation_contents;;
Syntax.Quotation.add "lam" Syntax.Quotation.DynAst.expr_tag expand_lambda_quot_expr;;
Syntax.Quotation.default := "lam";;
$ cat lambda_test.ml
let id = << fun x -> x >>
(* Imported and traduced from CCT *)
let zero = << fun s -> fun z -> z >>
let succ = << fun n -> fun s -> fun z -> s n >>
let one = << $succ$ $zero$ >>
let iota = << fun x -> z >>
let rho = << fun m -> fun r -> (s m (m r iota r)) >>
let rec_nat =
<< fun n -> fun s -> fun z -> n $rho$ $iota$ $rho$ >>
let plus = << fun n -> fun m -> $rec_nat$ n (fun n -> fun p -> $succ$ p) m >>
let times = << fun n -> fun m -> $rec_nat$ n (fun n -> fun p -> $plus$ m p) $zero$ >>
let fact = << fun n -> $rec_nat$ n (fun n -> fun p -> $times$ ($succ$ n) p) $one$ >>
$ ocamlc -c -I +camlp4 -I +camlp4/Camlp4Parsers -pp camlp4of -o lambda_quot_o.cmo lambda_quot_o.ml
$ camlp4of ./lambda_quot_o.cmo lambda_test.ml
let id = `Lam ("x", `Var "x")
(* Imported and traduced from CCT *)
let zero = `Lam ("s", `Lam ("z", `Var "z"))
let succ = `Lam ("n", `Lam ("s", `Lam ("z", `App (`Var "s", `Var "n"))))
let one = `App (succ, zero)
let iota = `Lam ("x", `Var "z")
let rho =
`Lam ("m",
`Lam ("r",
`App (`App (`Var "s", `Var "m"),
`App (`App (`App (`Var "m", `Var "r"), `Var "iota"), `Var "r"))))
let rec_nat =
`Lam ("n",
`Lam ("s", `Lam ("z", `App (`App (`App (`Var "n", rho), iota), rho))))
let plus =
`Lam ("n",
`Lam ("m",
`App
(`App (`App (rec_nat, `Var "n"),
`Lam ("n", `Lam ("p", `App (succ, `Var "p")))),
`Var "m")))
let times =
`Lam ("n",
`Lam ("m",
`App
(`App (`App (rec_nat, `Var "n"),
`Lam ("n", `Lam ("p", `App (`App (plus, `Var "m"), `Var "p")))),
zero)))
let fact =
`Lam ("n",
`App
(`App (`App (rec_nat, `Var "n"),
`Lam ("n",
`Lam ("p", `App (`App (times, `App (succ, `Var "n")), `Var "p")))),
one))