define Null object (#24)

JunNishimura · Sep 29, 2024 · f93a329 · f93a329
1 parent dc98b27
commit f93a329
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diff --git a/evaluator/evaluator.go b/evaluator/evaluator.go
@@ -8,6 +8,7 @@ import (
 )
 
 var (
+	Null  = &object.Null{}
 	True  = &object.Boolean{Value: true}
 	False = &object.Boolean{Value: false}
 )

diff --git a/object/object.go b/object/object.go
@@ -10,6 +10,7 @@ const (
 	INTEGER_OBJ = "INTEGER"
 	BOOLEAN_OBJ = "BOOLEAN"
 	ARRAY_OBJ   = "ARRAY"
+	NULL_OBJ    = "NULL"
 	BUILTIN_OBJ = "BUILTIN"
 )
 
@@ -54,6 +55,11 @@ func (a *Array) Inspect() string {
 	return out.String()
 }
 
+type Null struct{}
+
+func (n *Null) Type() ObjectType { return NULL_OBJ }
+func (n *Null) Inspect() string  { return "null" }
+
 type Error struct {
 	Message string
 }
-Original file line number
+Diff line change
@@ Expand Up / @@ -8,6 +8,7 @@ import ( @@
     )
     var (
+    	Null  = &object.Null{}
     	True  = &object.Boolean{Value: true}
     	False = &object.Boolean{Value: false}
     )
@@ Expand Down @@