Files
lci/lib/miniFun/TypeChecker.ml
2024-11-20 00:18:25 +01:00

208 lines
8.2 KiB
OCaml

module Utility = Utility
open Types;;
Random.self_init ()
let (let*) = Result.bind
let evaluate_type_polimorphic (_program: t_exp) (_context: typingshape) : (typingshape, error) result =
failwith "Not implemented"
(* match program with *)
(* Integer _ -> Ok (VariableMap.empty, IntegerType) *)
(* | Boolean _ -> Ok (VariableMap.empty, BooleanType) *)
(* | Variable x -> ( *)
(* match (VariableMap.find_opt x (fst context)) with *)
(* (None) -> ( *)
(* let u = PolimorphicType (Utility.fromIntToString !globalIdentifier) in *)
(* globalIdentifier := !globalIdentifier + 1; *)
(* Ok (VariableMap.singleton x u, u) *)
(* ) *)
(* | (Some u) -> Ok (VariableMap.singleton x u, u) *)
(* ) *)
(* | Function (xs, typef, fbody) -> failwith "Not Implemented" *)
(* | Application (f, xs) -> failwith "Not Implemented" *)
(* | Plus (x, y) *)
(* | Minus (x, y) *)
(* | Times (x, y) *)
(* | Division (x, y) *)
(* | Modulo (x, y) *)
(* | Power (x, y) -> ( *)
(* let* partialResx = evaluate_type x context in *)
(* let* partialResy = evaluate_type y context in *)
(* match (partialResx, partialResy) with *)
(* ((conx, IntegerType), (cony, IntegerType)) -> *)
(* Ok (VariableMap.union (fun _ x _ -> Some x) conx cony, *)
(* FunctionType ([IntegerType; IntegerType], IntegerType)) *)
(* | ((conx, PolimorphicType xv), (cony, IntegerType)) -> *)
(* Ok (unify ) *)
(* | ((_conx, IntegerType), (_cony, PolimorphicType _yv)) *)
(* | ((_conx, PolimorphicType _xv), (_cony, PolimorphicType _yv)) -> failwith "ads" *)
(* | (_, _) -> Error (`WrongType "The arguments are of the wrong type") *)
(* ) *)
(* | PowerMod (x, y, z) -> failwith "Not Implemented" *)
(* | Rand (x) -> failwith "Not Implemented" *)
(* | BAnd (x, y) *)
(* | BOr (x, y) -> failwith "Not Implemented" *)
(* | BNot (x) -> failwith "Not Implemented" *)
(* | Cmp (x, y) *)
(* | CmpLess (x, y) *)
(* | CmpLessEq (x, y) *)
(* | CmpGreater (x, y) *)
(* | CmpGreaterEq (x, y) -> failwith "Not Implemented" *)
(* | IfThenElse (guard, if_exp, else_exp) -> failwith "Not Implemented" *)
(* | LetIn (x, xval, rest) -> failwith "Not Implemented" *)
(* | LetFun (f, xs, typef, fbody, rest) -> failwith "Not Implemented" *)
let rec evaluate_type (program: t_exp) (context: ftype VariableMap.t) : (ftype, [> typechecking_error]) result =
match program with
Integer _ -> Ok IntegerType
| Boolean _ -> Ok BooleanType
| Variable x -> ( (* check for the type in the context *)
match VariableMap.find_opt x context with
None -> Error (`AbsentAssignment
("The variable " ^ x ^ " is not defined."))
| Some t -> Ok t
)
| Tuple (x, y) -> (
let* xtype = evaluate_type x context in
let* ytype = evaluate_type y context in
Ok (TupleType (xtype, ytype))
)
| Function (x, typef, fbody) -> (
(* first check that the function has the right specified type then check
the type of the body using the bindings for the input *)
match typef with
FunctionType (tin, tout) -> (
let* typefbody = evaluate_type fbody (VariableMap.add x tin context) in
if (typefbody = tout) then
Ok typef
else
Error (`WrongTypeSpecification
("Function does not return specified type."))
)
| _ -> Error (`WrongTypeSpecification
("Specification of function is not a function type."))
)
| Application (f, x) -> (
let* evalf = evaluate_type f context in
let* evalx = evaluate_type x context in
match evalf with
FunctionType (tin, tout) -> (
if tin = evalx then
Ok tout
else
Error (`WrongType "Appling function with wrong input type to value")
)
| _ -> Error (`WrongType "Applying to a non function type")
)
| Plus (x, y)
| Minus (x, y)
| Times (x, y)
| Division (x, y)
| Modulo (x, y)
| Power (x, y) -> (
let* typex = evaluate_type x context in
let* typey = evaluate_type y context in
match typex, typey with
| (IntegerType, IntegerType) -> Ok IntegerType
| (IntegerType, _) -> Error (`WrongType "Second term is not an integer.")
| (_, _) -> Error (`WrongType "First term is not an integer.")
)
| PowerMod (x, y, z) -> (
let* typex = evaluate_type x context in
let* typey = evaluate_type y context in
let* typez = evaluate_type z context in
match typex, typey, typez with
| (IntegerType, IntegerType, IntegerType) -> Ok IntegerType
| (IntegerType, IntegerType, _) -> Error (`WrongType ("Third term is " ^
"not an integer."))
| (IntegerType, _, _) -> Error (`WrongType
("Second term is not an integer."))
| (_, _, _) -> Error (`WrongType "First term is not an integer.")
)
| Rand (x) -> (
let* typex = evaluate_type x context in
match typex with
| (IntegerType) -> Ok IntegerType
| (_) -> Error (`WrongType "Term is not an integer.")
)
| BAnd (x, y)
| BOr (x, y) -> (
let* typex = evaluate_type x context in
let* typey = evaluate_type y context in
match typex, typey with
| (BooleanType, BooleanType) -> Ok BooleanType
| (BooleanType, _) -> Error (`WrongType "Second term is not a boolean.")
| (_, _) -> Error (`WrongType "First term is not a boolean.")
)
| BNot (x) -> (
let* typex = evaluate_type x context in
match typex with
| (BooleanType) -> Ok BooleanType
| (_) -> Error (`WrongType "Term is not a boolean.")
)
| First (x) -> (
let* typex = evaluate_type x context in
match typex with
| (TupleType (x, _)) -> Ok x
| (_) -> Error (`WrongType "Term is not a tuple.")
)
| Second (x) -> (
let* typex = evaluate_type x context in
match typex with
| (TupleType (_, x)) -> Ok x
| (_) -> Error (`WrongType "Term is not a tuple.")
)
| Cmp (x, y)
| CmpLess (x, y)
| CmpLessEq (x, y)
| CmpGreater (x, y)
| CmpGreaterEq (x, y) -> (
let* typex = evaluate_type x context in
let* typey = evaluate_type y context in
match typex, typey with
| (IntegerType, IntegerType) -> Ok BooleanType
| (IntegerType, _) -> Error (`WrongType "Second term is not an integer.")
| (_, _) -> Error (`WrongType "First term is not an integer.")
)
| IfThenElse (guard, if_exp, else_exp) -> (
let* typeguard = evaluate_type guard context in
let* typeif_exp = evaluate_type if_exp context in
let* typeelse_exp = evaluate_type else_exp context in
match typeguard, typeif_exp, typeelse_exp with
(BooleanType, t1, t2) -> (
if t1 = t2 then
Ok t1
else
Error (`WrongType "If branches do not have the same type.")
)
| (_, _, _) -> Error (`WrongType "If guard is not a boolean.")
)
| LetIn (x, xval, rest) ->
(* bind the type to the variable name in the context *)
let* typex = evaluate_type xval context in
evaluate_type rest (VariableMap.add x typex context)
| LetFun (f, x, typef, fbody, rest) ->
(* like with the function case, but also add f itself to the bindings *)
match typef with
FunctionType (tin, tout) -> (
let newcontext = VariableMap.add f typef context in
let newcontextwithx = VariableMap.add x tin newcontext in
let* typefbody = evaluate_type fbody newcontextwithx in
let* typerest = evaluate_type rest newcontext in
match (typefbody = tout, typerest) with
(false, _) -> Error (`WrongTypeSpecification
"Function does not return specified type.")
| (true, t) -> Ok t
)
| _ -> Error (`WrongTypeSpecification
"Specification of function is not a function type.")
let typecheck (program: t_exp) : (ftype, [> typechecking_error]) result =
let* typeprogram = evaluate_type program VariableMap.empty in
match typeprogram with
FunctionType (IntegerType, IntegerType) -> (
Ok (typeprogram)
)
| _ -> Error (`WrongType "Program is not a function from int to int.")