74 lines
2.6 KiB
OCaml
74 lines
2.6 KiB
OCaml
(* définition des différents types : tout est à reprendre et étendre *)
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type expr =
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Const of int
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| BConst of bool
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| Add of expr*expr
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| Mul of expr*expr
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| Min of expr*expr
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| Eq of expr*expr
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| Gt of expr*expr
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| Lt of expr*expr
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| Gte of expr*expr
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| Lte of expr*expr
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| Band of expr*expr
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| Bor of expr*expr
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| ITE of expr*expr*expr
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| PrInt of expr
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| Var of string
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| LetIn of string*expr*expr
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| Fun of string*expr
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| App of expr*expr
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type valeur = VInt of int | VBool of bool | VFunc of string*expr
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type env = (string*valeur) list
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let empty_env = []
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exception InvalidTypeException
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exception UnknownVariableException
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let rec readVar env v0 e = match env with
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| [] -> raise e
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| (v,x)::t -> if (v0 = v) then x else readVar t v0 e
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let rec intIntOp op e1 e2 env = match (eval e1 env, eval e2 env) with
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| VInt k1,VInt k2 -> VInt(op k1 k2)
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| _ -> raise InvalidTypeException
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and intBoolOp op e1 e2 env = match (eval e1 env, eval e2 env) with
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| VInt k1,VInt k2 -> VBool(op k1 k2)
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| _ -> raise InvalidTypeException
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(* sémantique opérationnelle à grands pas *)
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and eval e env = match e with
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| Const(k) -> VInt k
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| BConst(b) -> VBool b
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| Fun(v,e) -> VFunc(v,e)
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| Add(e1,e2) -> intIntOp ( + ) e1 e2 env
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| Mul(e1,e2) -> intIntOp ( * ) e1 e2 env
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| Min(e1,e2) -> intIntOp ( - ) e1 e2 env
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| Gt(e1,e2) -> intBoolOp ( > ) e1 e2 env
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| Lt(e1,e2) -> intBoolOp ( < ) e1 e2 env
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| Gte(e1,e2) -> intBoolOp ( >= ) e1 e2 env
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| Lte(e1,e2) -> intBoolOp ( <= ) e1 e2 env
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| Eq(e1,e2) -> (match (eval e1 env, eval e2 env) with
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| VInt k1,VInt k2 -> VBool (k1=k2)
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| VBool k1,VBool k2 -> VBool (k1=k2)
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| _ -> raise InvalidTypeException)
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| Band(e1,e2) -> (match (eval e1 env, eval e2 env) with
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| VBool b1,VBool b2 -> VBool (b1 && b2)
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| _ -> raise InvalidTypeException)
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| Bor(e1,e2) -> (match (eval e1 env, eval e2 env) with
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| VBool b1,VBool b2 -> VBool (b1 || b2)
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| _ -> raise InvalidTypeException)
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| ITE(ec,e1,e2) -> (match (eval ec env) with
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| VBool bc -> eval (if bc then e1 else e2) env
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| _ -> raise InvalidTypeException)
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| PrInt e1 -> (match (eval e1 env) with
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| VInt k -> VInt k
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| _ -> raise InvalidTypeException)
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| Var(v) -> readVar env v UnknownVariableException
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| LetIn(v,e0,e1) -> eval e1 ((v,eval e0 env)::env)
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| App(e0,e1) -> (match (eval e0 env) with
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| VFunc(v,e) -> eval (LetIn(v,e1,e)) env (* On utilise l'équivalence (fun x->e) y <=> let x=y in e *)
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| _ -> raise InvalidTypeException)
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