Switch statement analysis passes tests

analyzer/assignment.go

@@ -475,7 +475,7 @@ func isNumeric (ty entity.Type) bool {
 	}
 }
 
-// isInteger returns whether or not the specified type is an integer.
+// isInteger returns whether or not the specified type is an integer or word.
 func isInteger (ty entity.Type) bool {
 	switch ReduceToBase(ty).(type) {
 	case *entity.TypeInt, *entity.TypeWord: return true
@@ -483,6 +483,14 @@ func isInteger (ty entity.Type) bool {
 	}
 }
 
+// isWord returns whether or not the specified type is a word.
+func isWord (ty entity.Type) bool {
+	switch ReduceToBase(ty).(type) {
+	case *entity.TypeWord: return true
+	default: return false
+	}
+}
+
 // isPointer returns whether or not the specified type is a pointer.
 func isPointer (ty entity.Type) bool {
 	switch ReduceToBase(ty).(type) {

analyzer/expression.go

@@ -815,7 +815,8 @@ func (this *Tree) analyzeSwitch (
 	if err != nil { return nil, err }
 	switc.Value = value
 	width, integerOk := integerWidth(value.Type())
-	if !integerOk {
+	wordOk           := isWord(value.Type())
+	if !integerOk && !wordOk {
 		return nil, errors.Errorf (
 			value.Position(), "cannot switch on type %v",
 			value.Type())
@@ -843,6 +844,14 @@ func (this *Tree) analyzeSwitch (
 		case *entity.LiteralInt:
 			keyInt = int64(key.Value)
 		case *entity.LiteralString:
+			if !integerOk {
+				return nil, errors.Errorf (
+					key.Position(),
+					"cannot use string literal when " +
+					"switching on %v",
+					value.Type())
+			}
+		
 			switch {
 			case width >= 32:
 				keyInt = int64(key.ValueUTF32[0])
@@ -852,9 +861,17 @@ func (this *Tree) analyzeSwitch (
 				keyInt = int64(key.ValueUTF8[0])
 			}
 		default:
-		return nil, errors.Errorf (
+			return nil, errors.Errorf (
-			key.Position(), "%v cannot represent a constant integer",
+				key.Position(),
-			key)
+				"%v cannot represent a constant integer",
+				key)
+		}
+
+		if previous, exists := switc.CaseMap[keyInt]; exists {
+			return nil, errors.Errorf (
+				cas.Key.Position(),
+				"%v already listed in match at %v",
+				keyInt, previous.Position())
 		}
 		
 		switc.Cases[index]     = cas
@@ -873,7 +890,7 @@ func (this *Tree) analyzeSwitch (
 		switc.Default.Expression = expression
 	}
 
-	if into != nil && switc.Default != nil {
+	if into != nil && switc.Default == nil {
 		return nil, errors.Errorf (
 			switc.Position(),
 			"switch must have a default case")