111 lines
2.4 KiB
Go
111 lines
2.4 KiB
Go
package parser
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import (
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"fmt"
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"strconv"
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"git.sharkk.net/Sharkk/Mako/lexer"
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)
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type Parser struct {
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l *lexer.Lexer
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curToken lexer.Token
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peekToken lexer.Token
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errors []string
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}
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func New(l *lexer.Lexer) *Parser {
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p := &Parser{l: l, errors: []string{}}
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p.nextToken()
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p.nextToken()
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return p
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}
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func (p *Parser) nextToken() {
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p.curToken = p.peekToken
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p.peekToken = p.l.NextToken()
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}
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func (p *Parser) Errors() []string {
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return p.errors
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}
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func (p *Parser) ParseProgram() *Program {
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program := &Program{Statements: []Statement{}}
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for p.curToken.Type != lexer.TokenEOF {
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stmt := p.parseStatement()
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if stmt != nil {
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program.Statements = append(program.Statements, stmt)
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}
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p.nextToken()
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}
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return program
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}
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func (p *Parser) parseStatement() Statement {
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switch p.curToken.Type {
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case lexer.TokenIdentifier:
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if p.peekToken.Type == lexer.TokenEqual {
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return p.parseVariableStatement()
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}
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case lexer.TokenEcho:
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return p.parseEchoStatement()
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}
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return nil
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}
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func (p *Parser) parseVariableStatement() *VariableStatement {
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stmt := &VariableStatement{Token: p.curToken}
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stmt.Name = &Identifier{Token: p.curToken, Value: p.curToken.Value}
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p.nextToken() // Skip identifier
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p.nextToken() // Skip =
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switch p.curToken.Type {
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case lexer.TokenString:
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stmt.Value = &StringLiteral{Token: p.curToken, Value: p.curToken.Value}
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case lexer.TokenNumber:
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num, err := strconv.ParseFloat(p.curToken.Value, 64)
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if err != nil {
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p.errors = append(p.errors, fmt.Sprintf("could not parse %q as float", p.curToken.Value))
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}
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stmt.Value = &NumberLiteral{Token: p.curToken, Value: num}
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case lexer.TokenIdentifier:
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stmt.Value = &Identifier{Token: p.curToken, Value: p.curToken.Value}
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}
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if p.peekToken.Type == lexer.TokenSemicolon {
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p.nextToken()
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}
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return stmt
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}
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func (p *Parser) parseEchoStatement() *EchoStatement {
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stmt := &EchoStatement{Token: p.curToken}
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p.nextToken()
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switch p.curToken.Type {
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case lexer.TokenString:
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stmt.Value = &StringLiteral{Token: p.curToken, Value: p.curToken.Value}
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case lexer.TokenNumber:
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num, err := strconv.ParseFloat(p.curToken.Value, 64)
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if err != nil {
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p.errors = append(p.errors, fmt.Sprintf("could not parse %q as float", p.curToken.Value))
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}
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stmt.Value = &NumberLiteral{Token: p.curToken, Value: num}
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case lexer.TokenIdentifier:
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stmt.Value = &Identifier{Token: p.curToken, Value: p.curToken.Value}
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}
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if p.peekToken.Type == lexer.TokenSemicolon {
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p.nextToken()
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}
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return stmt
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}
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