- Formatting.
- Tracing information now displayed to better visualize how the program works. git-svn-id: https://svn.tlawal.org/svn/monkey@26 f6afcba9-9ef1-4bdd-9b72-7484f5705bac
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@ -52,6 +52,14 @@ type (
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infix_parse_function func(ast.Expression) ast.Expression
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)
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func (l_parser *Parser) register_prefix(l_token_type token.TokenType, l_function prefix_parse_function) {
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l_parser.prefix_parse_functions[l_token_type] = l_function
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}
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func (l_parser *Parser) register_infix(l_token_type token.TokenType, l_function infix_parse_function) {
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l_parser.infix_parse_functions[l_token_type] = l_function
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}
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type Parser struct {
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lexer *lexer.Lexer
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current_token token.Token
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@ -149,6 +157,7 @@ func (l_parser *Parser) parse_statement() ast.Statement {
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}
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func (l_parser *Parser) parse_let_statement() *ast.LetStatement {
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defer untrace(trace("parse_let_statement"))
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statement := &ast.LetStatement{Token: l_parser.current_token}
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if !l_parser.expect_peek(token.IDENT) {
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return nil
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@ -167,6 +176,7 @@ func (l_parser *Parser) parse_let_statement() *ast.LetStatement {
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}
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func (l_parser *Parser) parse_return_statement() *ast.ReturnStatement {
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defer untrace(trace("parse_return_statement"))
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statement := &ast.ReturnStatement{Token: l_parser.current_token}
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l_parser.next_token()
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@ -178,6 +188,7 @@ func (l_parser *Parser) parse_return_statement() *ast.ReturnStatement {
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}
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func (l_parser *Parser) parse_expression_statement() *ast.ExpressionStatement {
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defer untrace(trace("parse_expression_statement"))
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statement := &ast.ExpressionStatement{Token: l_parser.current_token}
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statement.Expression = l_parser.parse_expression(LOWEST)
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if l_parser.peek_token_is(token.SEMICOLON) {
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@ -186,19 +197,13 @@ func (l_parser *Parser) parse_expression_statement() *ast.ExpressionStatement {
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return statement
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}
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func (l_parser *Parser) register_prefix(l_token_type token.TokenType, l_function prefix_parse_function) {
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l_parser.prefix_parse_functions[l_token_type] = l_function
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}
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func (l_parser *Parser) parse_identifier() ast.Expression {
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defer untrace(trace("parse_identifier"))
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return &ast.Identifier{Token: l_parser.current_token, Value: l_parser.current_token.Literal}
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}
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func (l_parser *Parser) register_infix(l_token_type token.TokenType, l_function infix_parse_function) {
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l_parser.infix_parse_functions[l_token_type] = l_function
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}
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func (l_parser *Parser) parse_integer_literal() ast.Expression {
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defer untrace(trace("parse_integer_literal"))
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literal := &ast.IntegerLiteral{Token: l_parser.current_token}
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value, error := strconv.ParseInt(l_parser.current_token.Literal, 0, 64)
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if error != nil {
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@ -212,6 +217,7 @@ func (l_parser *Parser) parse_integer_literal() ast.Expression {
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// Here lies the heart of Pratt Parsing
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func (l_parser *Parser) parse_expression(precedence int) ast.Expression {
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defer untrace(trace("parse_expression"))
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prefix := l_parser.prefix_parse_functions[l_parser.current_token.Type]
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if prefix == nil {
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l_parser.no_prefix_parse_function_error(l_parser.current_token.Type)
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@ -231,12 +237,8 @@ func (l_parser *Parser) parse_expression(precedence int) ast.Expression {
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return left_expression
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}
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func (l_parser *Parser) no_prefix_parse_function_error(l_token_type token.TokenType) {
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message := fmt.Sprintf("no prefix parse function for %s, found", l_token_type)
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l_parser.errors = append(l_parser.errors, message)
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}
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func (l_parser *Parser) parse_prefix_expression() ast.Expression {
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defer untrace(trace("parse_prefix_expression"))
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expression := &ast.PrefixExpression{
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Token: l_parser.current_token,
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Operator: l_parser.current_token.Literal,
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@ -247,6 +249,7 @@ func (l_parser *Parser) parse_prefix_expression() ast.Expression {
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}
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func (l_parser *Parser) parse_infix_expression(left ast.Expression) ast.Expression {
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defer untrace(trace("parse_prefix_expression"))
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expression := &ast.InfixExpression{
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Token: l_parser.current_token,
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Operator: l_parser.current_token.Literal,
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@ -258,3 +261,8 @@ func (l_parser *Parser) parse_infix_expression(left ast.Expression) ast.Expressi
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return expression
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}
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func (l_parser *Parser) no_prefix_parse_function_error(l_token_type token.TokenType) {
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message := fmt.Sprintf("no prefix parse function for %s, found", l_token_type)
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l_parser.errors = append(l_parser.errors, message)
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}
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