X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=code%2Fcalculator%2Fcalc1.ml;h=b0c5cea766b3aea45b28f65bd808e07219fa0de5;hp=35b32ffb7db6029982a017b2a157ffce6866bc32;hb=911d868126d0b91047b362cb909cdfeb503cd16b;hpb=bd90f2eb8b87c2f44169fe209c5e35dd113c3d21

diff --git a/code/calculator/calc1.ml b/code/calculator/calc1.ml
index 35b32ffb..b0c5cea7 100644
--- a/code/calculator/calc1.ml
+++ b/code/calculator/calc1.ml
@@ -1,6 +1,6 @@
-(* Original calculator from Week7, enhanced with Booleans and Immutable Pairs *)
+(* calc1.ml: original calculator from Week7, enhanced with Booleans and Immutable Pairs *)
 
-	type term =
+    type term =
       Intconstant of int
     | Multiplication of (term * term)
     | Addition of (term * term)
@@ -12,47 +12,47 @@
     | First of term
     ;;
 
-	type expressed_value = Int of int | Bool of bool | Pair of expressed_value * expressed_value;;
-	type bound_value = expressed_value;;
-	type assignment = (char * bound_value) list;;
+    type expressed_value = Int of int | Bool of bool | Pair of expressed_value * expressed_value;;
+    type bound_value = expressed_value;;
+    type assignment = (char * bound_value) list;;
 
-	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 t2 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
+    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 t2 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
     ;;