X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=code%2Fcalculator%2Fcalc2.ml;h=ef4a37c6ca981c0c83fd6a54025776a2ebd24d0f;hp=9db0dea61123e1e5da5e58b36f67857b963dc081;hb=060198e29e2a13552ee64c1e489eea555c8b1cae;hpb=12c7bba12e14ab2e1ea72a4b95f1aee0c114a188

diff --git a/code/calculator/calc2.ml b/code/calculator/calc2.ml
index 9db0dea6..ef4a37c6 100644
--- a/code/calculator/calc2.ml
+++ b/code/calculator/calc2.ml
@@ -1,68 +1,68 @@
 (* calc1.ml, enhanced with 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)
-        ;;
+    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)
+    ;;
 
     type bound_value = expressed_value
-	and assignment = (char * bound_value) list
+    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 *)
-		List.assoc var g
-	| Let (var_to_bind, t2, t3) ->
-		(* evaluate t3 under a new assignment where var_to_bind has been bound to
-		   the result of evaluating t1 under the current assignment *)
-		let value2 = eval t2 g
-		in let g' = (var_to_bind, 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 value2 *)
-		in let savedg' = (arg_var, value2) :: savedg
-		in eval body savedg'
+    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 *)
+        List.assoc var g
+    | Let (var_to_bind, t2, t3) ->
+        (* evaluate t3 under a new assignment where var_to_bind has been bound to
+           the result of evaluating t1 under the current assignment *)
+        let value2 = eval t2 g
+        in let g' = (var_to_bind, 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 value2 *)
+        in let savedg' = (arg_var, value2) :: savedg
+        in eval body savedg'
     ;;