X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=code%2Fcalculator%2Fcalc3.ml;fp=code%2Fcalculator%2Fcalc3.ml;h=0000000000000000000000000000000000000000;hp=523a6bbf4b75bb303d7e7130780f99ff59f6e760;hb=fd698b815e417dec463cb0f0e9ed056ab83daed6;hpb=573a8b36ce653c84c2aecb2b81ef99128cb41d13

diff --git a/code/calculator/calc3.ml b/code/calculator/calc3.ml
deleted file mode 100644
index 523a6bbf..00000000
--- a/code/calculator/calc3.ml
+++ /dev/null
@@ -1,82 +0,0 @@
-(* calc3.ml: calc2.ml enhanced with Recursive Function Values *)
-
-    type term =
-      Intconstant of int
-    | Multiplication of (term * term)
-    | Addition of (term * term)
-    | Variable of char
-    | Let of (char * term * term)
-    | Iszero of term
-    | If of (term * term * term)
-    | Makepair of (term * term)
-    | First of term
-    | Lambda of (char * term)
-    | Apply of (term * term)
-    | Letrec of (char * term * term)
-    ;;
-
-    type bound_value = Nonrecursive of expressed_value | Recursive_Closure of char * char * term * assignment
-    and assignment = (char * bound_value) list
-    and expressed_value = Int of int | Bool of bool | Pair of expressed_value * expressed_value | Closure of char * term * assignment;;
-
-    let rec eval (t : term) (g : assignment) = match t with
-      Intconstant x -> Int x
-    | Multiplication (t1, t2) ->
-        (* we don't handle cases where the subterms don't evaluate to Ints *)
-        let Int i1 = eval t1 g
-        in let Int i2 = eval t2 g
-        (* Multiplication (t1, t2) should evaluate to an Int *)
-        in Int (i1 * i2)
-    | Addition (t1, t2) ->
-        let Int i1 = eval t1 g
-        in let Int i2 = eval t2 g
-        in Int (i1 + i2)
-    | Variable (var) -> (
-        (* we don't handle cases where g doesn't bind var to any value *)
-        match List.assoc var g with
-          | Nonrecursive value -> value
-          | Recursive_Closure (self_var, arg_var, body, savedg) as rec_closure ->
-              (* we update savedg to bind self_var to rec_closure here *)
-              let savedg' = (self_var, rec_closure) :: savedg
-              in Closure (arg_var, body, savedg')
-        )
-    | Let (var_to_bind, t2, t3) ->
-        (* evaluate t3 under a new assignment where var_to_bind has been bound to
-           the result of evaluating t2 under the current assignment *)
-        let value2 = eval t2 g
-        (* we have to wrap value2 in Nonrecursive *)
-        in let g' = (var_to_bind, Nonrecursive value2) :: g
-        in eval t3 g'
-    | Iszero (t1) ->
-        (* we don't handle cases where t1 doesn't evaluate to an Int *)
-        let Int i1 = eval t1 g
-        (* Iszero t1 should evaluate to a Bool *)
-        in Bool (i1 = 0)
-    | If (t1, t2, t3) ->
-        (* we don't handle cases where t1 doesn't evaluate to a boolean *)
-        let Bool b1 = eval t1 g
-        in if b1 then eval t2 g
-        else eval t3 g
-    | Makepair (t1, t2) ->
-        let value1 = eval t1 g
-        in let value2 = eval t2 g
-        in Pair (value1, value2)
-    | First (t1) ->
-        (* we don't handle cases where t1 doesn't evaluate to a Pair *)
-        let Pair (value1, value2) = eval t1 g
-        in value1
-    | Lambda (arg_var, t2) -> Closure (arg_var, t2, g)
-    | Apply (t1, t2) ->
-        (* we don't handle cases where t1 doesn't evaluate to a function value *)
-        let Closure (arg_var, body, savedg) = eval t1 g
-        in let value2 = eval t2 g
-        (* evaluate body under savedg, except with arg_var bound to Nonrecursive value2 *)
-        in let savedg' = (arg_var, Nonrecursive value2) :: savedg
-        in eval body savedg'
-    | Letrec (var_to_bind, t2, t3) ->
-        (* we don't handle cases where t2 doesn't evaluate to a function value *)
-        let Closure (arg_var, body, savedg) = eval t2 g
-        (* evaluate t3 under a new assignment where var_to_bind has been recursively bound to that function value *) 
-        in let g' = (var_to_bind, Recursive_Closure (var_to_bind, arg_var, body, savedg)) :: g
-        in eval t3 g'
-    ;;