public static IMemberExpression Parse(string text, int start, int count, Action <string> onError)
{
if (string.IsNullOrEmpty(text))
{
return(null);
}
if (start < 0 || start >= text.Length)
{
throw new ArgumentOutOfRangeException(nameof(start));
}
if (count < 1)
{
count = text.Length - start;
}
else if (count > text.Length - start)
{
throw new ArgumentOutOfRangeException(nameof(count));
}
//创建解析上下文对象
var context = new StateContext(text.Length, onError);
//状态迁移驱动
for (int i = start; i < start + count; i++)
{
context.Character = text[i];
switch (context.State)
{
case State.None:
if (!DoNone(ref context, i))
{
return(null);
}
break;
case State.Gutter:
if (!DoGutter(ref context, i))
{
return(null);
}
break;
case State.Separator:
if (!DoSeparator(ref context, i))
{
return(null);
}
break;
case State.Identifier:
if (!DoIdentifier(ref context, i))
{
return(null);
}
break;
case State.Method:
if (!DoMethod(ref context, i))
{
return(null);
}
break;
case State.Indexer:
if (!DoIndexer(ref context, i))
{
return(null);
}
break;
case State.Parameter:
if (!DoParameter(ref context, i))
{
return(null);
}
break;
case State.Number:
if (!DoNumber(ref context, i))
{
return(null);
}
break;
case State.String:
if (!DoString(ref context, i))
{
return(null);
}
break;
}
}
//获取最终的解析结果
return(context.GetResult());
}
