//用例:
//estr="sum(1,2,3,sin((4+5)*10),acos(cos(70)),avg(1,2,3,4,5,6,7,8,9))+2e+4";
//Expression.evaluate(estr);
/**
* @author jh7086
*/
class Expression {
//为方便检测"+ -"是否为正负号,限用单个字符的运算符
private static var ostr : String = "+,-,*,/,%,^,e";
private static var oarr : Array = ostr.split(",");
private static var fstr : String = "abs,round,sqrt,sin,cos,tan,acos,asin,atan,log,exp,sum,avg,count,max,min";
private static var farr : Array = fstr.split(",