Implement the full arithmetic part of the ISO spec.

1 files changed, 5 insertions, 37 deletions

diff --git a/builtins.c b/builtins.c
index 95b6438..885db3c 100644
--- a/builtins.c
+++ b/builtins.c
@@ -475,37 +475,6 @@ builtincopyterm(Term *goal, Binding **bindings, Module *module)
 	return unify(term2, t, bindings);
 }
 
-#define ToFloat(t) (t->tag == IntegerTerm ? (double)t->ival : t->dval)
-
-Term *
-aritheval(Term *expr)
-{
-	/* Not every arithmetic operation is defined right now. */
-
-	if(expr->tag == FloatTerm || expr->tag == IntegerTerm)
-		return expr;
-	else if(expr->tag == CompoundTerm && expr->arity == 2){
-		Term *A = aritheval(expr->children);
-		Term *B = aritheval(expr->children->next);
-		Term *result = mkinteger(0);
-
-		if(A == nil || B == nil)
-			return nil;
-		if(runestrcmp(expr->text, L"+") == 0){
-			if(A->tag == IntegerTerm && B->tag == IntegerTerm){
-				result->tag = IntegerTerm;
-				result->ival = A->ival + B->ival;
-			}else{
-				result->tag = FloatTerm;
-				result->dval = ToFloat(A) + ToFloat(B);
-			}
-		}else
-			return nil;
-		return result;
-	}else
-		return nil;
-}
-
 int
 builtinis(Term *goal, Binding **bindings, Module *module)
 {
@@ -513,12 +482,11 @@ builtinis(Term *goal, Binding **bindings, Module *module)
 	Term *result = goal->children;
 	Term *expr = result->next;
 
-	
-	Term *realresult = aritheval(expr);
-	if(realresult)
-		return unify(result, realresult, bindings);
-	else
-		return 0;
+	int waserror;
+	Term *realresult = aritheval(expr, &waserror);
+	if(waserror)
+		Throw(realresult);
+	return unify(result, realresult, bindings);
 }
 
 int