Simplified Equality

object/array.go

@@ -13,6 +13,7 @@ type Array struct {
 func (ao *Array) Type() ObjectType {
 	return ARRAY_OBJ
 }
+
 func (ao *Array) Inspect() string {
 	var out bytes.Buffer
 
@@ -30,25 +31,34 @@ func (ao *Array) Inspect() string {
 func (ao *Array) String() string {
 	return ao.Inspect()
 }
-func (ao *Array) Equal(other Object) bool {
+
+func (a *Array) Less(i, j int) bool {
+	if cmp, ok := a.Elements[i].(Comparable); ok {
+		return cmp.Compare(a.Elements[j]) == -1
+	}
+	return false
+}
+
+func (ao *Array) Compare(other Object) int {
 	if obj, ok := other.(*Array); ok {
 		if len(ao.Elements) != len(obj.Elements) {
-			return false
+			return -1
 		}
 		for i, el := range ao.Elements {
 			cmp, ok := el.(Comparable)
 			if !ok {
-				return false
+				return -1
 			}
-			if !cmp.Equal(obj.Elements[i]) {
-				return false
+			if cmp.Compare(obj.Elements[i]) != 0 {
+				return cmp.Compare(obj.Elements[i])
 			}
 		}
 
-		return true
+		return 0
 	}
-	return false
+	return -1
 }
+
 func (ao *Array) Copy() *Array {
 	elements := make([]Object, len(ao.Elements))
 	for i, e := range ao.Elements {
@@ -70,10 +80,3 @@ func (ao *Array) Len() int {
 func (ao *Array) Swap(i, j int) {
 	ao.Elements[i], ao.Elements[j] = ao.Elements[j], ao.Elements[i]
 }
-
-func (ao *Array) Less(i, j int) bool {
-	if cmp, ok := ao.Elements[i].(Comparable); ok {
-		return cmp.Less(ao.Elements[j])
-	}
-	return false
-}

object/bool.go

@@ -11,31 +11,29 @@ type Boolean struct {
 func (b *Boolean) Type() ObjectType {
 	return BOOLEAN_OBJ
 }
+
 func (b *Boolean) Inspect() string {
 	return fmt.Sprintf("%t", b.Value)
 }
+
 func (b *Boolean) Clone() Object {
 	return &Boolean{Value: b.Value}
 }
+
 func (b *Boolean) String() string {
 	return b.Inspect()
 }
-func (b *Boolean) Equal(other Object) bool {
-	if obj, ok := other.(*Boolean); ok {
-		return b.Value == obj.Value
-	}
-	return false
-}
-func (b *Boolean) Int() int64 {
+
+func (b *Boolean) Int() int {
 	if b.Value {
 		return 1
 	}
 	return 0
 }
 
-func (b *Boolean) Less(other Object) bool {
+func (b *Boolean) Compare(other Object) int {
 	if obj, ok := other.(*Boolean); ok {
-		return b.Int() < obj.Int()
+		return b.Int() - obj.Int()
 	}
-	return false
+	return 1
 }

object/hash.go

@@ -47,6 +47,7 @@ type Hash struct {
 func (h *Hash) Type() ObjectType {
 	return HASH_OBJ
 }
+
 func (h *Hash) Inspect() string {
 	var out bytes.Buffer
 
@@ -64,28 +65,29 @@ func (h *Hash) Inspect() string {
 func (h *Hash) String() string {
 	return h.Inspect()
 }
-func (h *Hash) Equal(other Object) bool {
+
+func (h *Hash) Compare(other Object) int {
 	if obj, ok := other.(*Hash); ok {
 		if len(h.Pairs) != len(obj.Pairs) {
-			return false
+			return -1
 		}
 		for _, pair := range h.Pairs {
 			left := pair.Value
 			hashed := left.(Hashable)
 			right, ok := obj.Pairs[hashed.HashKey()]
 			if !ok {
-				return false
+				return -1
 			}
 			cmp, ok := left.(Comparable)
 			if !ok {
-				return false
+				return -1
 			}
-			if !cmp.Equal(right.Value) {
-				return false
+			if cmp.Compare(right.Value) != 0 {
+				return cmp.Compare(right.Value)
 			}
 		}
 
-		return true
+		return 0
 	}
-	return false
+	return -1
 }

object/int.go

@@ -9,24 +9,29 @@ type Integer struct {
 func (i *Integer) Type() ObjectType {
 	return INTEGER_OBJ
 }
+
 func (i *Integer) Inspect() string {
 	return fmt.Sprintf("%d", i.Value)
 }
+
 func (i *Integer) Clone() Object {
 	return &Integer{Value: i.Value}
 }
+
 func (i *Integer) String() string {
 	return i.Inspect()
 }
-func (i *Integer) Equal(other Object) bool {
+
+func (i *Integer) Compare(other Object) int {
 	if obj, ok := other.(*Integer); ok {
-		return i.Value == obj.Value
+		switch {
+		case i.Value < obj.Value:
+			return -1
+		case i.Value > obj.Value:
+			return 1
+		default:
+			return 0
+		}
 	}
-	return false
-}
-func (i *Integer) Less(other Object) bool {
-	if obj, ok := other.(*Integer); ok {
-		return i.Value < obj.Value
-	}
-	return true
+	return -1
 }

object/null.go

@@ -5,16 +5,18 @@ type Null struct{}
 func (n *Null) Type() ObjectType {
 	return NULL_OBJ
 }
+
 func (n *Null) Inspect() string {
 	return "null"
 }
+
 func (n *Null) String() string {
 	return n.Inspect()
 }
-func (n *Null) Equal(other Object) bool {
-	_, ok := other.(*Null)
-	return ok
-}
-func (n *Null) Less(other Object) bool {
-	return false
+
+func (n *Null) Compare(other Object) int {
+	if _, ok := other.(*Null); ok {
+		return 0
+	}
+	return 1
 }

object/object.go

@@ -22,8 +22,7 @@ const (
 // values. It is the responsibility of the caller (left) to check for types.
 // Returns `true` iif the types and values are identical, `false` otherwise.
 type Comparable interface {
-	Equal(other Object) bool
-	Less(other Object) bool
+	Compare(other Object) int
 }
 
 // Immutable is the interface for all immutable objects which must implement

object/str.go

@@ -9,24 +9,29 @@ type String struct {
 func (s *String) Type() ObjectType {
 	return STRING_OBJ
 }
+
 func (s *String) Inspect() string {
 	return fmt.Sprintf("%#v", s.Value)
 }
+
 func (s *String) Clone() Object {
 	return &String{Value: s.Value}
 }
+
 func (s *String) String() string {
 	return s.Value
 }
-func (s *String) Equal(other Object) bool {
+
+func (s *String) Compare(other Object) int {
 	if obj, ok := other.(*String); ok {
-		return s.Value == obj.Value
+		switch {
+		case s.Value < obj.Value:
+			return -1
+		case s.Value > obj.Value:
+			return 1
+		default:
+			return 0
+		}
 	}
-	return false
-}
-func (s *String) Less(other Object) bool {
-	if obj, ok := other.(*String); ok {
-		return s.Value < obj.Value
-	}
-	return false
+	return 1
 }