/// <summary>
/// 解析
/// </summary>
private void Analyze()
{
if (_link_OP == null)
{
if (_expression.Trim().Length > 0)
{
PhraseAnalyzer analyze = new PhraseAnalyzer(_expression);
_link_OP = analyze.Analyze();
}
else
{
throw new Exception("Error! 表达式为空");
}
}
}
/// <summary>
/// 词法分析
/// </summary>
public Link_OP Analyze()
{
_link_OP = new Link_OP();
char[] chArray = _expression.Trim().ToCharArray();
int i = 0;
int startpos = 0;
int endpos = 0;
EDFAState prestate = EDFAState.Start; //DFA的前一个状态
while (i < chArray.Length)
{
if (prestate == EDFAState.CharStr)
{
//字符串结构 - 字符串结构是处理当前态 - 其它类型是处理上一态
if (chArray[i] == '"' && chArray[i - 1] != '\\')
{
endpos = i;
AddToLink(startpos, endpos, prestate);
prestate = EDFAState.Start;
startpos = i + 1;
}
else if (i + 1 == chArray.Length)
{
throw new Exception("Error! 词法.缺少字符串引号（\"）");
}
}
else if (chArray[i] == '"')
{
//字符串开始
if (prestate != EDFAState.Start)
{
endpos = i - 1;
AddToLink(startpos, endpos, prestate);
startpos = i;
}
prestate = EDFAState.CharStr;
}
else if (Char.IsLetter(chArray[i]))
{
//字母
if (prestate == EDFAState.Start)
{
prestate = EDFAState.ABCStr;
}
else if (prestate != EDFAState.ABCStr)
{
//处理前一个词
endpos = i - 1; //保存结束位置
AddToLink(startpos, endpos, prestate);
prestate = EDFAState.ABCStr;
startpos = i; //保存开始位置
}
}
else if (Char.IsDigit(chArray[i]))
{
//数字
if (prestate == EDFAState.Start)
{
prestate = EDFAState.IntStr;
}
else if (prestate != EDFAState.IntStr && prestate != EDFAState.DoubleStr)
{
endpos = i - 1;
AddToLink(startpos, endpos, prestate);
prestate = EDFAState.IntStr;
startpos = i;
}
}
else if (chArray[i] == '.')
{
//小数点
if (prestate == EDFAState.IntStr)
{
prestate = EDFAState.DoubleStr;
}
else
{
throw new Exception(string.Format("Error! 词法.错误的小数点位置,索引：{0}", i.ToString()));
}
}
else if (chArray[i] == ',')
{
//逗号
endpos = i - 1;
AddToLink(startpos, endpos, prestate);
prestate = EDFAState.Comma;
startpos = i;
}
else if (Char.IsWhiteSpace(chArray[i]) || chArray[i] == '\r' || chArray[i] == '\n' || chArray[i] == '\t')
{
//空格，回车，制表符 跳过
}
else if (chArray[i] == '(' || chArray[i] == ')' || chArray[i] == '+' || chArray[i] == '-' || chArray[i] == '*' ||
chArray[i] == '/' || chArray[i] == '%' || chArray[i] == '>' || chArray[i] == '<' || chArray[i] == '=')
{
//操作符只能是单值符号+多值符号在链表添加时处理
if (prestate != EDFAState.Start)
{
endpos = i - 1;
AddToLink(startpos, endpos, prestate);
startpos = i;
}
prestate = EDFAState.OperatorStr;
}
else
{
throw new Exception(string.Format("Error! 词法.非法字符“{0}”（索引：{1}）", chArray[i].ToString(), i.ToString()));
}
i++;
if (i == chArray.Length)
{
endpos = i - 1;
if (startpos == endpos && chArray[endpos] == '"')
{
throw new Exception("Error! 词法.缺少字符串引号（\"）");
}
AddToLink(startpos, endpos, prestate);
}
}// end while
return(_link_OP);
}
