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git-svn-id: https://svn.tlawal.org/svn/monkey@26 f6afcba9-9ef1-4bdd-9b72-7484f5705bac
This commit is contained in:
Tijani Lawal 2022-05-31 17:38:50 +00:00
parent e5d95dc7b6
commit 982efec3d0
2 changed files with 22 additions and 14 deletions
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34
parser/parser.go
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@ -52,6 +52,14 @@ type (
infix_parse_function func(ast.Expression) ast.Expression
)
func (l_parser *Parser) register_prefix(l_token_type token.TokenType, l_function prefix_parse_function) {
l_parser.prefix_parse_functions[l_token_type] = l_function
}
func (l_parser *Parser) register_infix(l_token_type token.TokenType, l_function infix_parse_function) {
l_parser.infix_parse_functions[l_token_type] = l_function
}
type Parser struct {
lexer *lexer.Lexer
current_token token.Token
@ -149,6 +157,7 @@ func (l_parser *Parser) parse_statement() ast.Statement {
}
func (l_parser *Parser) parse_let_statement() *ast.LetStatement {
defer untrace(trace("parse_let_statement"))
statement := &ast.LetStatement{Token: l_parser.current_token}
if !l_parser.expect_peek(token.IDENT) {
return nil
@ -167,6 +176,7 @@ func (l_parser *Parser) parse_let_statement() *ast.LetStatement {
}
func (l_parser *Parser) parse_return_statement() *ast.ReturnStatement {
defer untrace(trace("parse_return_statement"))
statement := &ast.ReturnStatement{Token: l_parser.current_token}
l_parser.next_token()
@ -178,6 +188,7 @@ func (l_parser *Parser) parse_return_statement() *ast.ReturnStatement {
}
func (l_parser *Parser) parse_expression_statement() *ast.ExpressionStatement {
defer untrace(trace("parse_expression_statement"))
statement := &ast.ExpressionStatement{Token: l_parser.current_token}
statement.Expression = l_parser.parse_expression(LOWEST)
if l_parser.peek_token_is(token.SEMICOLON) {
@ -186,19 +197,13 @@ func (l_parser *Parser) parse_expression_statement() *ast.ExpressionStatement {
return statement
}
func (l_parser *Parser) register_prefix(l_token_type token.TokenType, l_function prefix_parse_function) {
l_parser.prefix_parse_functions[l_token_type] = l_function
}
func (l_parser *Parser) parse_identifier() ast.Expression {
defer untrace(trace("parse_identifier"))
return &ast.Identifier{Token: l_parser.current_token, Value: l_parser.current_token.Literal}
}
func (l_parser *Parser) register_infix(l_token_type token.TokenType, l_function infix_parse_function) {
l_parser.infix_parse_functions[l_token_type] = l_function
}
func (l_parser *Parser) parse_integer_literal() ast.Expression {
defer untrace(trace("parse_integer_literal"))
literal := &ast.IntegerLiteral{Token: l_parser.current_token}
value, error := strconv.ParseInt(l_parser.current_token.Literal, 0, 64)
if error != nil {
@ -212,6 +217,7 @@ func (l_parser *Parser) parse_integer_literal() ast.Expression {
// Here lies the heart of Pratt Parsing
func (l_parser *Parser) parse_expression(precedence int) ast.Expression {
defer untrace(trace("parse_expression"))
prefix := l_parser.prefix_parse_functions[l_parser.current_token.Type]
if prefix == nil {
l_parser.no_prefix_parse_function_error(l_parser.current_token.Type)
@ -231,12 +237,8 @@ func (l_parser *Parser) parse_expression(precedence int) ast.Expression {
return left_expression
}
func (l_parser *Parser) no_prefix_parse_function_error(l_token_type token.TokenType) {
message := fmt.Sprintf("no prefix parse function for %s, found", l_token_type)
l_parser.errors = append(l_parser.errors, message)
}
func (l_parser *Parser) parse_prefix_expression() ast.Expression {
defer untrace(trace("parse_prefix_expression"))
expression := &ast.PrefixExpression{
Token: l_parser.current_token,
Operator: l_parser.current_token.Literal,
@ -247,6 +249,7 @@ func (l_parser *Parser) parse_prefix_expression() ast.Expression {
}
func (l_parser *Parser) parse_infix_expression(left ast.Expression) ast.Expression {
defer untrace(trace("parse_prefix_expression"))
expression := &ast.InfixExpression{
Token: l_parser.current_token,
Operator: l_parser.current_token.Literal,
@ -258,3 +261,8 @@ func (l_parser *Parser) parse_infix_expression(left ast.Expression) ast.Expressi
return expression
}
func (l_parser *Parser) no_prefix_parse_function_error(l_token_type token.TokenType) {
message := fmt.Sprintf("no prefix parse function for %s, found", l_token_type)
l_parser.errors = append(l_parser.errors, message)
}