164 lines
3.4 KiB
Go
164 lines
3.4 KiB
Go
package ast
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import (
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"bytes"
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"monkey/token"
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)
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type PrefixExpression struct {
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Token token.Token // The prefix token, e.g. !
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Operator string
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Right Expression
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}
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func (pe *PrefixExpression) expressionNode() {}
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func (pe *PrefixExpression) TokenLiteral() string { return pe.Token.Literal }
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func (pe *PrefixExpression) String() string {
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var out bytes.Buffer
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out.WriteString("(")
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out.WriteString(pe.Operator)
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out.WriteString(pe.Right.String())
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out.WriteString(")")
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return out.String()
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}
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type LetStatement struct {
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Token token.Token // the token.LET token
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Name *Identifier
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Value Expression
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}
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func (ls *LetStatement) statementNode() {}
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func (ls *LetStatement) TokenLiteral() string { return ls.Token.Literal }
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type Identifier struct {
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Token token.Token // the token.IDENT token
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Value string
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}
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func (i *Identifier) expressionNode() {}
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func (i *Identifier) TokenLiteral() string { return i.Token.Literal }
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type Node interface {
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TokenLiteral() string
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String() string
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}
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type Statement interface {
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Node
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statementNode()
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}
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type Expression interface {
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Node
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expressionNode()
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}
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type Program struct {
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Statements []Statement
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}
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type IntegerLiteral struct {
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Token token.Token
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Value int64
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}
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func (p *Program) TokenLiteral() string {
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if len(p.Statements) > 0 {
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return p.Statements[0].TokenLiteral()
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} else {
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return ""
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}
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}
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func (il *IntegerLiteral) expressionNode() {}
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func (il *IntegerLiteral) TokenLiteral() string { return il.Token.Literal }
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func (il *IntegerLiteral) String() string { return il.Token.Literal }
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type ExpressionStatement struct {
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Token token.Token // the first token of the expression
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Expression Expression
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}
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func (es *ExpressionStatement) statementNode() {}
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func (es *ExpressionStatement) TokenLiteral() string { return es.Token.Literal }
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func (p *Program) String() string {
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var out bytes.Buffer
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for _, s := range p.Statements {
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out.WriteString(s.String())
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}
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return out.String()
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}
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type ReturnStatement struct {
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Token token.Token // the 'return' token
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ReturnValue Expression
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}
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func (rs *ReturnStatement) statementNode() {}
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func (rs *ReturnStatement) TokenLiteral() string { return rs.Token.Literal }
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func (ls *LetStatement) String() string {
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var out bytes.Buffer
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out.WriteString(ls.TokenLiteral() + " ")
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out.WriteString(ls.Name.String())
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out.WriteString(" = ")
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if ls.Value != nil {
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out.WriteString(ls.Value.String())
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}
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out.WriteString(";")
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return out.String()
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}
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func (rs *ReturnStatement) String() string {
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var out bytes.Buffer
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out.WriteString(rs.TokenLiteral() + " ")
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if rs.ReturnValue != nil {
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out.WriteString(rs.ReturnValue.String())
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}
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out.WriteString(";")
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return out.String()
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}
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func (es *ExpressionStatement) String() string {
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if es.Expression != nil {
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return es.Expression.String()
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}
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return ""
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}
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func (i *Identifier) String() string { return i.Value }
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type InfixExpression struct {
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Token token.Token // The operator token, e.g. +
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Left Expression
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Operator string
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Right Expression
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}
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func (oe *InfixExpression) expressionNode() {}
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func (oe *InfixExpression) TokenLiteral() string { return oe.Token.Literal }
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func (oe *InfixExpression) String() string {
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var out bytes.Buffer
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out.WriteString("(")
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out.WriteString(oe.Left.String())
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out.WriteString(" " + oe.Operator + " ")
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out.WriteString(oe.Right.String())
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out.WriteString(")")
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return out.String()
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} |