optimizations

internal/object/array.go

@@ -63,11 +63,8 @@ func (ao *Array) String() string {
 	return ao.Inspect()
 }
 
-func (ao *Array) Less(i, j int) bool {
-	if cmp, ok := ao.Elements[i].(Comparable); ok {
-		return cmp.Compare(ao.Elements[j]) == -1
-	}
-	return false
+func (a *Array) Less(i, j int) bool {
+	return a.Elements[i].Compare(a.Elements[j]) == -1
 }
 
 func (a *Array) Add(other Object) (Object, error) {
@@ -129,18 +126,15 @@ func (ao *Array) Set(index, other Object) error {
 	return nil
 }
 
-func (ao *Array) Compare(other Object) int {
+func (a *Array) Compare(other Object) int {
 	if obj, ok := other.(*Array); ok {
-		if len(ao.Elements) != len(obj.Elements) {
+		if len(a.Elements) != len(obj.Elements) {
 			return -1
 		}
-		for i, el := range ao.Elements {
-			cmp, ok := el.(Comparable)
-			if !ok {
-				return -1
-			}
-			if cmp.Compare(obj.Elements[i]) != 0 {
-				return cmp.Compare(obj.Elements[i])
+		for i, el := range a.Elements {
+			val := el.Compare(obj.Elements[i])
+			if val != 0 {
+				return val
 			}
 		}
 

internal/object/builtin.go

@@ -19,6 +19,19 @@ func (b Builtin) Inspect() string {
 	return fmt.Sprintf("<built-in function %s>", b.Name)
 }
 
+func (b Builtin) Compare(other Object) int {
+	if obj, ok := other.(Builtin); ok {
+		if b.Name > obj.Name {
+			return 1
+		}
+		if b.Name == obj.Name {
+			return 0
+		}
+		return -1
+	}
+	return -1
+}
+
 func (b Builtin) String() string {
 	return b.Inspect()
 }

internal/object/closure.go

@@ -23,11 +23,16 @@ func (cf *CompiledFunction) Inspect() string {
 	return fmt.Sprintf("CompiledFunction[%p]", cf)
 }
 
+func (cf CompiledFunction) Compare(other Object) int {
+	return -1
+}
+
 func (cf *CompiledFunction) String() string {
 	return cf.Inspect()
 }
 
 type Closure struct {
+	BaseObject
 	Fn   *CompiledFunction
 	Free []Object
 }

internal/object/error.go

@@ -23,6 +23,23 @@ func (e Error) Copy() Object {
 	return Error{Message: e.Message}
 }
 
+func (e Error) Compare(other Object) int {
+	if obj, ok := other.(Error); ok {
+		if e.Message > obj.Message {
+			return 1
+		}
+		if e.Message == obj.Message {
+			return 0
+		}
+		return -1
+	}
+	return -1
+}
+
+func (e Error) Error() string {
+	return e.Message
+}
+
 func (e Error) String() string {
 	return e.Message
 }

internal/object/function.go

@@ -7,6 +7,8 @@ import (
 )
 
 type Function struct {
+	BaseObject
+
 	Parameters []*ast.Identifier
 	Body       *ast.BlockStatement
 	Env        *Environment
@@ -43,6 +45,7 @@ func (f Function) String() string {
 }
 
 type ReturnValue struct {
+	BaseObject
 	Value Object
 }
 

internal/object/hash.go

@@ -97,18 +97,14 @@ func (h *Hash) Compare(other Object) int {
 			return -1
 		}
 		for _, pair := range h.Pairs {
-			left := pair.Value
-			hashed := left.(Hasher)
+			hashed := pair.Value.(Hasher)
 			right, ok := obj.Pairs[hashed.Hash()]
 			if !ok {
 				return -1
 			}
-			cmp, ok := left.(Comparable)
-			if !ok {
-				return -1
-			}
-			if cmp.Compare(right.Value) != 0 {
-				return cmp.Compare(right.Value)
+			val := pair.Value.Compare(right.Value)
+			if val != 0 {
+				return val
 			}
 		}
 

internal/object/object.go

@@ -57,11 +57,6 @@ func (t Type) String() string {
 	}
 }
 
-// Comparable is the interface for objects to implement suitable comparisons
-type Comparable interface {
-	Compare(other Object) int
-}
-
 // Copyable is the interface for creating copies of objects
 type Copyable interface {
 	Copy() Object
@@ -73,9 +68,14 @@ type Object interface {
 	fmt.Stringer
 	Type() Type
 	Bool() bool
+	Compare(Object) int
 	Inspect() string
 }
 
+type BaseObject struct{}
+
+func (o BaseObject) Compare(other Object) int { return -1 }
+
 // Hasher is the interface for objects to provide suitable hash keys
 type Hasher interface {
 	Hash() HashKey