feat(lexer): added new tokens

added == and !=

1 files changed, 48 insertions, 0 deletions

diff --git a/ast/ast.go b/ast/ast.go
new file mode 100644
index 0000000..033005f
--- /dev/null
+++ b/ast/ast.go
@@ -0,0 +1,48 @@
+package ast
+
+import (
+	"github.com/mewsen/interpreter/token"
+)
+
+type Node interface {
+	TokenLiteral() string
+}
+
+type Statement interface {
+	Node
+	statementNode()
+}
+
+type Expression interface {
+	Node
+	expressionNode()
+}
+
+type Program struct {
+	Statements []Statement
+}
+
+func (p *Program) TokenLiteral() string {
+	if len(p.Statements) > 0 {
+		return p.Statements[0].TokenLiteral()
+	} else {
+		return ""
+	}
+}
+
+type LetStatement struct {
+	Token token.Token
+	Name  *Identifier
+	Value Expression
+}
+
+func (ls *LetStatement) statementNode()       {}
+func (ls *LetStatement) TokenLiteral() string { return ls.Token.Literal }
+
+type Identifier struct {
+	Token token.Token
+	Value string
+}
+
+func (i *Identifier) expressionNode()      {}
+func (i *Identifier) TokenLiteral() string { return i.Token.Literal }