basic expression interpreter

runtime/types.go

@@ -1,5 +1,7 @@
 package runtime
 
+import "fmt"
+
 //go:generate stringer -type LoxType -trimprefix LoxType
 type LoxType int
 
@@ -19,15 +21,81 @@ func (v *LoxValue) Type() LoxType {
 	switch v.raw.(type) {
 	case string:
 		return LoxTypeString
-	case float64, float32:
+	case float64:
 		return LoxTypeNumber
 	case bool:
 		return LoxTypeBoolean
+	case nil:
+		return LoxTypeNil
 	default:
 		return LoxTypeUndefined
 	}
 }
 
+func (v *LoxValue) Debug() string {
+	return fmt.Sprintf("%+v", v.raw)
+}
+
+func (v *LoxValue) String() string {
+	if string, ok := v.raw.(string); ok {
+		return string
+	}
+	return ""
+}
+
+func (v *LoxValue) Number() float64 {
+	if number, ok := v.raw.(float64); ok {
+		return number
+	}
+	return 0.0
+}
+
+func (v *LoxValue) IsString() bool {
+	return v.Type() == LoxTypeString
+}
+
+func (v *LoxValue) IsNumber() bool {
+	return v.Type() == LoxTypeNumber
+}
+func (v *LoxValue) IsTruthy() bool {
+	switch v.Type() {
+	case LoxTypeBoolean:
+		b, ok := v.raw.(bool)
+		return ok && b
+	case LoxTypeNumber, LoxTypeString:
+		return true
+	default:
+		return false
+	}
+}
+
+func (v *LoxValue) IsNil() bool {
+	return v.Type() == LoxTypeNil
+}
+
+func (v *LoxValue) IsUndefined() bool {
+	return v.Type() == LoxTypeUndefined
+}
+
+func (v *LoxValue) Equals(other *LoxValue) bool {
+	return AreEqual(v, other)
+}
+
 func Value(v any) *LoxValue {
 	return &LoxValue{v}
 }
+
+func AreEqual(a, b *LoxValue) bool {
+	typeA := a.Type()
+	typeB := b.Type()
+
+	if typeA != typeB {
+		return false
+	}
+
+	return a.raw == b.raw
+}
+
+func AreEqualValue(a, b *LoxValue) *LoxValue {
+	return Value(AreEqual(a, b))
+}