pakmanaged.js
function expectKeyword(keyword, contextual) {
            var token = lex();
            if (token.type !== (contextual ? Token.Identifier : Token.Keyword) ||
                    token.value !== keyword) {
                throwUnexpected(token);
            }
        }
function expectKeyword(keyword, contextual) {
            var token = lex();
            if (token.type !== (contextual ? Token.Identifier : Token.Keyword) ||
                    token.value !== keyword) {
                throwUnexpected(token);
            }
        }
Expect the next token to match the specified keyword. If not, an exception will be thrown.