update
add string test case
add string test case
init arasy.parser
update arasy.expressionParser
convert normal token type to expressionTokenType
init parser
update demo. import expression parse source files
remove useless code
add adjustExpressionType.
When the parser.scanner gets a token, convert its token type to expressionTokenType
update adjustExpressionType.
update adjustExpressionType.
refactor. tokenType to TokenType
update expressionParser
bugfix。after nextToken,  set lookaheadTokenConsumed = true;
update expressionParser.parser
update expressionParser.commaParser
update expressionParser.operatorParser
update parser.parseExpressionStatement
remove old useless code