123 lines
2.5 KiB
Go
123 lines
2.5 KiB
Go
// Package token defines constants representing the lexical tokens of JavaScript (ECMA5).
|
|
package token
|
|
|
|
import (
|
|
"strconv"
|
|
)
|
|
|
|
// Token is the set of lexical tokens in JavaScript (ECMA5).
|
|
type Token int
|
|
|
|
// String returns the string corresponding to the token.
|
|
// For operators, delimiters, and keywords the string is the actual
|
|
// token string (e.g., for the token PLUS, the String() is
|
|
// "+"). For all other tokens the string corresponds to the token
|
|
// name (e.g. for the token IDENTIFIER, the string is "IDENTIFIER").
|
|
func (tkn Token) String() string {
|
|
if tkn == 0 {
|
|
return "UNKNOWN"
|
|
}
|
|
if tkn < Token(len(token2string)) {
|
|
return token2string[tkn]
|
|
}
|
|
return "token(" + strconv.Itoa(int(tkn)) + ")"
|
|
}
|
|
|
|
//lint:ignore U1000 This is not used for anything
|
|
func (tkn Token) precedence(in bool) int {
|
|
|
|
switch tkn {
|
|
case LOGICAL_OR:
|
|
return 1
|
|
|
|
case LOGICAL_AND:
|
|
return 2
|
|
|
|
case OR, OR_ASSIGN:
|
|
return 3
|
|
|
|
case EXCLUSIVE_OR:
|
|
return 4
|
|
|
|
case AND, AND_ASSIGN:
|
|
return 5
|
|
|
|
case EQUAL,
|
|
NOT_EQUAL,
|
|
STRICT_EQUAL,
|
|
STRICT_NOT_EQUAL:
|
|
return 6
|
|
|
|
case LESS, GREATER, LESS_OR_EQUAL, GREATER_OR_EQUAL, INSTANCEOF:
|
|
return 7
|
|
|
|
case IN:
|
|
if in {
|
|
return 7
|
|
}
|
|
return 0
|
|
|
|
case SHIFT_LEFT, SHIFT_RIGHT, UNSIGNED_SHIFT_RIGHT:
|
|
fallthrough
|
|
case SHIFT_LEFT_ASSIGN, SHIFT_RIGHT_ASSIGN, UNSIGNED_SHIFT_RIGHT_ASSIGN:
|
|
return 8
|
|
|
|
case PLUS, MINUS, ADD_ASSIGN, SUBTRACT_ASSIGN:
|
|
return 9
|
|
|
|
case MULTIPLY, SLASH, REMAINDER, MULTIPLY_ASSIGN, QUOTIENT_ASSIGN, REMAINDER_ASSIGN:
|
|
return 11
|
|
}
|
|
return 0
|
|
}
|
|
|
|
type _keyword struct {
|
|
token Token
|
|
futureKeyword bool
|
|
strict bool
|
|
}
|
|
|
|
// IsKeyword returns the keyword token if literal is a keyword, a KEYWORD token
|
|
// if the literal is a future keyword (const, let, class, super, ...), or 0 if the literal is not a keyword.
|
|
//
|
|
// If the literal is a keyword, IsKeyword returns a second value indicating if the literal
|
|
// is considered a future keyword in strict-mode only.
|
|
//
|
|
// 7.6.1.2 Future Reserved Words:
|
|
//
|
|
// const
|
|
// class
|
|
// enum
|
|
// export
|
|
// extends
|
|
// import
|
|
// super
|
|
//
|
|
// 7.6.1.2 Future Reserved Words (strict):
|
|
//
|
|
// implements
|
|
// interface
|
|
// let
|
|
// package
|
|
// private
|
|
// protected
|
|
// public
|
|
// static
|
|
func IsKeyword(literal string) (Token, bool) {
|
|
if keyword, exists := keywordTable[literal]; exists {
|
|
if keyword.futureKeyword {
|
|
return KEYWORD, keyword.strict
|
|
}
|
|
return keyword.token, false
|
|
}
|
|
return 0, false
|
|
}
|
|
|
|
func IsId(tkn Token) bool {
|
|
return tkn >= IDENTIFIER
|
|
}
|
|
|
|
func IsUnreservedWord(tkn Token) bool {
|
|
return tkn > ESCAPED_RESERVED_WORD
|
|
}
|