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package ast
import (
"bytes"
"github.com/mewsen/interpreter/token"
)
type Node interface {
TokenLiteral() string
String() 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 ""
}
}
func (p *Program) String() string {
var out bytes.Buffer
for _, s := range p.Statements {
out.WriteString(s.String())
}
return out.String()
}
type LetStatement struct {
Token token.Token
Name *Identifier
Value Expression
}
func (ls *LetStatement) statementNode() {}
func (ls *LetStatement) TokenLiteral() string { return ls.Token.Literal }
func (ls *LetStatement) String() string {
var out bytes.Buffer
out.WriteString(ls.TokenLiteral() + " ")
out.WriteString(ls.Name.String())
out.WriteString(" = ")
if ls.Value != nil {
out.WriteString(ls.Value.String())
}
return out.String()
}
type Identifier struct {
Token token.Token
Value string
}
func (i *Identifier) expressionNode() {}
func (i *Identifier) TokenLiteral() string { return i.Token.Literal }
func (i *Identifier) String() string { return i.Value }
type ReturnStatement struct {
Token token.Token
ReturnValue Expression
}
func (rs *ReturnStatement) statementNode() {}
func (rs *ReturnStatement) TokenLiteral() string { return rs.Token.Literal }
func (rs *ReturnStatement) String() string {
var out bytes.Buffer
out.WriteString(rs.TokenLiteral() + " ")
if rs.ReturnValue != nil {
out.WriteString(rs.ReturnValue.String())
}
out.WriteString(";")
return out.String()
}
type ExpressionStatement struct {
Token token.Token
Expression Expression
}
func (es *ExpressionStatement) statementNode() {}
func (es *ExpressionStatement) TokenLiteral() string { return es.Token.Literal }
func (es *ExpressionStatement) String() string {
if es.Expression != nil {
return es.Expression.String()
}
return ""
}
type IntegerLiteral struct {
Token token.Token
Value int64
}
func (il *IntegerLiteral) expressionNode() {}
func (il *IntegerLiteral) TokenLiteral() string { return il.Token.Literal }
func (il *IntegerLiteral) String() string { return il.Token.Literal }
type PrefixExpression struct {
Token token.Token
Operator string
Right Expression
}
func (pe *PrefixExpression) expressionNode() {}
func (pe *PrefixExpression) TokenLiteral() string { return pe.Token.Literal }
func (pe *PrefixExpression) String() string {
var out bytes.Buffer
out.WriteString("(")
out.WriteString(pe.Operator)
out.WriteString(pe.Right.String())
out.WriteString(")")
return out.String()
}
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