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ast.go
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ast.go
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package ast
import (
"bytes"
"fmt"
"github.com/goby-lang/goby/token"
"strings"
)
type node interface {
TokenLiteral() string
String() string
}
type Statement interface {
node
statementNode()
}
type Expression interface {
node
expressionNode()
}
// Program is the root node of entire AST
type Program struct {
Statements []Statement
}
func (p *Program) TokenLiteral() string {
if len(p.Statements) > 0 {
return p.Statements[0].TokenLiteral()
}
return ""
}
func (p *Program) String() string {
var out bytes.Buffer
for _, s := range p.Statements {
out.WriteString(s.String())
}
return out.String()
}
type DefStatement struct {
Token token.Token
Name *Identifier
Receiver Expression
Parameters []*Identifier
BlockStatement *BlockStatement
}
func (ds *DefStatement) statementNode() {}
func (ds *DefStatement) TokenLiteral() string {
return ds.Token.Literal
}
func (ds *DefStatement) String() string {
var out bytes.Buffer
out.WriteString("def ")
out.WriteString(ds.Name.TokenLiteral())
out.WriteString("(")
for i, param := range ds.Parameters {
out.WriteString(param.String())
if i != len(ds.Parameters)-1 {
out.WriteString(", ")
}
}
out.WriteString(") ")
out.WriteString("{\n")
out.WriteString(ds.BlockStatement.String())
out.WriteString("\n}")
return out.String()
}
type ClassStatement struct {
Token token.Token
Name *Constant
Body *BlockStatement
SuperClass Expression
SuperClassName string
}
func (cs *ClassStatement) statementNode() {}
func (cs *ClassStatement) TokenLiteral() string {
return cs.Token.Literal
}
func (cs *ClassStatement) String() string {
var out bytes.Buffer
out.WriteString("class ")
out.WriteString(cs.Name.TokenLiteral())
out.WriteString(" {\n")
out.WriteString(cs.Body.String())
out.WriteString("\n}")
return out.String()
}
// ModuleStatement represents module node in AST
type ModuleStatement struct {
Token token.Token
Name *Constant
Body *BlockStatement
SuperClass *Constant
}
func (ms *ModuleStatement) statementNode() {}
// TokenLiteral returns token's literal
func (ms *ModuleStatement) TokenLiteral() string {
return ms.Token.Literal
}
func (ms *ModuleStatement) String() string {
var out bytes.Buffer
out.WriteString("module ")
out.WriteString(ms.Name.TokenLiteral())
out.WriteString(" {\n")
out.WriteString(ms.Body.String())
out.WriteString("\n}")
return out.String()
}
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 int
}
func (il *IntegerLiteral) expressionNode() {}
func (il *IntegerLiteral) TokenLiteral() string {
return il.Token.Literal
}
func (il *IntegerLiteral) String() string {
return il.Token.Literal
}
type StringLiteral struct {
Token token.Token
Value string
}
func (sl *StringLiteral) expressionNode() {}
func (sl *StringLiteral) TokenLiteral() string {
return sl.Token.Literal
}
func (sl *StringLiteral) String() string {
var out bytes.Buffer
out.WriteString("\"")
out.WriteString(sl.Token.Literal)
out.WriteString("\"")
return out.String()
}
type ArrayExpression struct {
Token token.Token
Elements []Expression
}
func (ae *ArrayExpression) expressionNode() {}
func (ae *ArrayExpression) TokenLiteral() string {
return ae.Token.Literal
}
func (ae *ArrayExpression) String() string {
var out bytes.Buffer
out.WriteString("[")
if len(ae.Elements) == 0 {
out.WriteString("]")
return out.String()
}
out.WriteString(ae.Elements[0].String())
for _, elem := range ae.Elements[1:] {
out.WriteString(", ")
out.WriteString(elem.String())
}
out.WriteString("]")
return out.String()
}
type HashExpression struct {
Token token.Token
Data map[string]Expression
}
func (he *HashExpression) expressionNode() {}
func (he *HashExpression) TokenLiteral() string {
return he.Token.Literal
}
func (he *HashExpression) String() string {
var out bytes.Buffer
var pairs []string
for key, value := range he.Data {
pairs = append(pairs, fmt.Sprintf("%s: %s", key, value.String()))
}
out.WriteString("{ ")
out.WriteString(strings.Join(pairs, ", "))
out.WriteString(" }")
return out.String()
}
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()
}
type InfixExpression struct {
Token token.Token
Left Expression
Operator string
Right Expression
}
func (ie *InfixExpression) expressionNode() {}
func (ie *InfixExpression) TokenLiteral() string {
return ie.Token.Literal
}
func (ie *InfixExpression) String() string {
var out bytes.Buffer
out.WriteString("(")
out.WriteString(ie.Left.String())
out.WriteString(" ")
out.WriteString(ie.Operator)
out.WriteString(" ")
out.WriteString(ie.Right.String())
out.WriteString(")")
return out.String()
}
type BooleanExpression struct {
Token token.Token
Value bool
}
func (b *BooleanExpression) expressionNode() {}
func (b *BooleanExpression) TokenLiteral() string {
return b.Token.Literal
}
func (b *BooleanExpression) String() string {
return b.Token.Literal
}
// NilExpression represents nil node
type NilExpression struct {
Token token.Token
}
func (n *NilExpression) expressionNode() {}
// TokenLiteral returns `nil`
func (n *NilExpression) TokenLiteral() string {
return n.Token.Literal
}
// String returns `nil`
func (n *NilExpression) String() string {
return "nil"
}
type IfExpression struct {
Token token.Token
Condition Expression
Consequence *BlockStatement
Alternative *BlockStatement
}
func (ie *IfExpression) expressionNode() {}
func (ie *IfExpression) TokenLiteral() string {
return ie.Token.Literal
}
func (ie *IfExpression) String() string {
var out bytes.Buffer
out.WriteString("if")
out.WriteString(" ")
out.WriteString(ie.Condition.String())
out.WriteString("\n")
out.WriteString(ie.Consequence.String())
if ie.Alternative != nil {
out.WriteString("\n")
out.WriteString("else\n")
out.WriteString(ie.Alternative.String())
}
out.WriteString("\nend")
return out.String()
}
type BlockStatement struct {
Token token.Token // {
Statements []Statement
}
func (bs *BlockStatement) statementNode() {}
func (bs *BlockStatement) TokenLiteral() string {
return bs.Token.Literal
}
func (bs *BlockStatement) String() string {
var out bytes.Buffer
for _, stmt := range bs.Statements {
out.WriteString(stmt.String())
}
return out.String()
}
type CallExpression struct {
Receiver Expression
Token token.Token
Method string
Arguments []Expression
Block *BlockStatement
BlockArguments []*Identifier
}
func (ce *CallExpression) expressionNode() {}
func (ce *CallExpression) TokenLiteral() string {
return ce.Token.Literal
}
func (ce *CallExpression) String() string {
var out bytes.Buffer
out.WriteString(ce.Receiver.String())
out.WriteString(".")
out.WriteString(ce.Method)
var args = []string{}
for _, arg := range ce.Arguments {
args = append(args, arg.String())
}
out.WriteString("(")
out.WriteString(strings.Join(args, ", "))
out.WriteString(")")
if ce.Block != nil {
var blockArgs []string
out.WriteString(" do")
if len(ce.BlockArguments) > 0 {
for _, arg := range ce.BlockArguments {
blockArgs = append(blockArgs, arg.String())
}
out.WriteString(" |")
out.WriteString(strings.Join(blockArgs, ", "))
out.WriteString("|")
}
out.WriteString("\n")
out.WriteString(ce.Block.String())
out.WriteString("\nend")
}
return out.String()
}
type SelfExpression struct {
Token token.Token
}
func (se *SelfExpression) expressionNode() {}
func (se *SelfExpression) TokenLiteral() string {
return se.Token.Literal
}
func (se *SelfExpression) String() string {
return "self"
}
type WhileStatement struct {
Token token.Token
Condition Expression
Body *BlockStatement
}
func (ws *WhileStatement) statementNode() {}
func (ws *WhileStatement) TokenLiteral() string {
return ws.Token.Literal
}
func (ws *WhileStatement) String() string {
var out bytes.Buffer
out.WriteString("while ")
out.WriteString(ws.Condition.String())
out.WriteString(" do\n")
out.WriteString(ws.Body.String())
out.WriteString("\nend")
return out.String()
}
type YieldExpression struct {
Token token.Token
Arguments []Expression
}
func (ye *YieldExpression) expressionNode() {}
func (ye *YieldExpression) TokenLiteral() string {
return ye.Token.Literal
}
func (ye *YieldExpression) String() string {
var out bytes.Buffer
var args []string
for _, arg := range ye.Arguments {
args = append(args, arg.String())
}
out.WriteString(ye.TokenLiteral())
out.WriteString("(")
out.WriteString(strings.Join(args, ", "))
out.WriteString(")")
return out.String()
}