expressions working

Signed-off-by: Casey Lee <cplee@nektos.com>

vendor/github.com/robertkrimen/otto/token/token.go

@@ -0,0 +1,116 @@
+// 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 0 == tkn {
+		return "UNKNOWN"
+	}
+	if tkn < Token(len(token2string)) {
+		return token2string[tkn]
+	}
+	return "token(" + strconv.Itoa(int(tkn)) + ")"
+}
+
+// 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, AND_NOT, AND_NOT_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
+}