func (self *_parser) scan() (tkn token.Token, literal string, idx file.Idx) {
self.implicitSemicolon = false
for {
self.skipWhiteSpace()
idx = self.idxOf(self.chrOffset)
insertSemicolon := false
switch chr := self.chr; {
case isIdentifierStart(chr):
var err error
literal, err = self.scanIdentifier()
if err != nil {
tkn = token.ILLEGAL
break
}
if len(literal) > 1 {
// Keywords are longer than 1 character, avoid lookup otherwise
var strict bool
tkn, strict = token.IsKeyword(literal)
switch tkn {
case 0: // Not a keyword
if literal == "true" || literal == "false" {
self.insertSemicolon = true
tkn = token.BOOLEAN
return
} else if literal == "null" {
self.insertSemicolon = true
tkn = token.NULL
return
}
case token.KEYWORD:
tkn = token.KEYWORD
if strict {
// TODO If strict and in strict mode, then this is not a break
break
}
return
case
token.THIS,
token.BREAK,
token.THROW, // A newline after a throw is not allowed, but we need to detect it
token.RETURN,
token.CONTINUE,
token.DEBUGGER:
self.insertSemicolon = true
return
default:
return
}
}
self.insertSemicolon = true
tkn = token.IDENTIFIER
return
case '0' <= chr && chr <= '9':
self.insertSemicolon = true
tkn, literal = self.scanNumericLiteral(false)
return
default:
self.read()
switch chr {
case -1:
if self.insertSemicolon {
self.insertSemicolon = false
self.implicitSemicolon = true
}
tkn = token.EOF
case '\r', '\n', '\u2028', '\u2029':
self.insertSemicolon = false
self.implicitSemicolon = true
continue
case ':':
tkn = token.COLON
case '.':
if digitValue(self.chr) < 10 {
insertSemicolon = true
tkn, literal = self.scanNumericLiteral(true)
} else {
tkn = token.PERIOD
}
case ',':
tkn = token.COMMA
case ';':
tkn = token.SEMICOLON
case '(':
tkn = token.LEFT_PARENTHESIS
case ')':
tkn = token.RIGHT_PARENTHESIS
insertSemicolon = true
case '[':
tkn = token.LEFT_BRACKET
case ']':
tkn = token.RIGHT_BRACKET
insertSemicolon = true
case '{':
tkn = token.LEFT_BRACE
case '}':
tkn = token.RIGHT_BRACE
insertSemicolon = true
case '+':
tkn = self.switch3(token.PLUS, token.ADD_ASSIGN, '+', token.INCREMENT)
if tkn == token.INCREMENT {
insertSemicolon = true
}
case '-':
tkn = self.switch3(token.MINUS, token.SUBTRACT_ASSIGN, '-', token.DECREMENT)
if tkn == token.DECREMENT {
insertSemicolon = true
}
case '*':
tkn = self.switch2(token.MULTIPLY, token.MULTIPLY_ASSIGN)
case '/':
if self.chr == '/' {
self.skipSingleLineComment()
continue
} else if self.chr == '*' {
self.skipMultiLineComment()
continue
} else {
// Could be division, could be RegExp literal
tkn = self.switch2(token.SLASH, token.QUOTIENT_ASSIGN)
insertSemicolon = true
}
case '%':
tkn = self.switch2(token.REMAINDER, token.REMAINDER_ASSIGN)
case '^':
tkn = self.switch2(token.EXCLUSIVE_OR, token.EXCLUSIVE_OR_ASSIGN)
case '<':
tkn = self.switch4(token.LESS, token.LESS_OR_EQUAL, '<', token.SHIFT_LEFT, token.SHIFT_LEFT_ASSIGN)
case '>':
tkn = self.switch6(token.GREATER, token.GREATER_OR_EQUAL, '>', token.SHIFT_RIGHT, token.SHIFT_RIGHT_ASSIGN, '>', token.UNSIGNED_SHIFT_RIGHT, token.UNSIGNED_SHIFT_RIGHT_ASSIGN)
case '=':
tkn = self.switch2(token.ASSIGN, token.EQUAL)
if tkn == token.EQUAL && self.chr == '=' {
self.read()
tkn = token.STRICT_EQUAL
}
case '!':
tkn = self.switch2(token.NOT, token.NOT_EQUAL)
if tkn == token.NOT_EQUAL && self.chr == '=' {
self.read()
tkn = token.STRICT_NOT_EQUAL
}
case '&':
if self.chr == '^' {
self.read()
tkn = self.switch2(token.AND_NOT, token.AND_NOT_ASSIGN)
} else {
tkn = self.switch3(token.AND, token.AND_ASSIGN, '&', token.LOGICAL_AND)
}
case '|':
tkn = self.switch3(token.OR, token.OR_ASSIGN, '|', token.LOGICAL_OR)
case '~':
tkn = token.BITWISE_NOT
case '?':
tkn = token.QUESTION_MARK
case '"', '\'':
insertSemicolon = true
tkn = token.STRING
var err error
literal, err = self.scanString(self.chrOffset - 1)
if err != nil {
tkn = token.ILLEGAL
}
case '`':
insertSemicolon = true
tkn = token.STRING
var err error
literal, err = self.scanMultiString(self.chrOffset - 1)
if err != nil {
tkn = token.ILLEGAL
}
default:
self.errorUnexpected(idx, chr)
tkn = token.ILLEGAL
}
}
self.insertSemicolon = insertSemicolon
return
}
}
func (self *_parser) parsePrimaryExpression() ast.Expression {
literal := self.literal
idx := self.idx
switch self.token {
case token.IDENTIFIER:
self.next()
if len(literal) > 1 {
tkn, strict := token.IsKeyword(literal)
if tkn == token.KEYWORD {
if !strict {
self.error(idx, "Unexpected reserved word")
}
}
}
return &ast.Identifier{
Name: literal,
Idx: idx,
}
case token.NULL:
self.next()
return &ast.NullLiteral{
Idx: idx,
Literal: literal,
}
case token.BOOLEAN:
self.next()
value := false
switch literal {
case "true":
value = true
case "false":
value = false
default:
self.error(idx, "Illegal boolean literal")
}
return &ast.BooleanLiteral{
Idx: idx,
Literal: literal,
Value: value,
}
case token.STRING:
self.next()
value, err := parseStringLiteral(literal[1 : len(literal)-1])
if err != nil {
self.error(idx, err.Error())
}
return &ast.StringLiteral{
Idx: idx,
Literal: literal,
Value: value,
}
case token.NUMBER:
self.next()
value, err := parseNumberLiteral(literal)
if err != nil {
self.error(idx, err.Error())
value = 0
}
return &ast.NumberLiteral{
Idx: idx,
Literal: literal,
Value: value,
}
case token.SLASH, token.QUOTIENT_ASSIGN:
return self.parseRegExpLiteral()
case token.LEFT_BRACE:
return self.parseObjectLiteral()
case token.LEFT_BRACKET:
return self.parseArrayLiteral()
case token.LEFT_PARENTHESIS:
self.expect(token.LEFT_PARENTHESIS)
expression := self.parseExpression()
self.expect(token.RIGHT_PARENTHESIS)
return expression
case token.THIS:
self.next()
return &ast.ThisExpression{
Idx: idx,
}
case token.FUNCTION:
return self.parseFunction(false)
}
self.errorUnexpectedToken(self.token)
self.nextStatement()
return &ast.BadExpression{From: idx, To: self.idx}
}