/// <summary>
/// 解析表达式
/// </summary>
/// <param name="text"></param>
public void Parse(string text)
{
this._Text = text;
DCTokenList tokens = new DCTokenList(text);
this._RootItem = new DCGroupExpressionItem();
ParseItem(this._RootItem, tokens);
}
private void toolStripButton1_Click(object sender, EventArgs e)
{
DCTokenList tokens = new DCTokenList(cboExpression.Text);
StringBuilder result = new StringBuilder();
for (int iCount = 0; iCount < tokens.Count; iCount++)
{
result.AppendLine(iCount.ToString("00") + ":" + tokens[iCount].ToString());
}
DCExpression exp = new DCExpression(cboExpression.Text);
result.AppendLine(exp.ToDebugString());
MyContext c = new MyContext();
object vresult = exp.Eval(c);
result.AppendLine("运算结果:" + vresult);
txtResult.Text = result.ToString();
}
/// <summary>
/// 解析表达式项目
/// </summary>
/// <param name="rootItem"></param>
/// <param name="tokens"></param>
private void ParseItem(DCExpressionItem rootItem, DCTokenList tokens)
{
List <DCExpressionItem> items = new List <DCExpressionItem>();
while (tokens.MoveNext())
{
DCExpressionItem newItem = null;
DCToken token = tokens.Current;
if (token.Type == CharType.Symbol)
{
// 根据关键字 And Or 进行修复。
if (string.Equals(token.Text, "And", StringComparison.CurrentCultureIgnoreCase))
{
token.Type = CharType.MathOperator;
token.Text = "&&";
}
else if (string.Equals(token.Text, "or", StringComparison.CurrentCultureIgnoreCase))
{
token.Type = CharType.MathOperator;
token.Text = "||";
}
}
if (token.Type == CharType.Symbol)
{
// 标识符
DCToken next = tokens.NextItem;
if (next != null && next.Type == CharType.CurLeft)
{
// 函数调用
tokens.MoveNext();
DCFunctionExpressionItem func = new DCFunctionExpressionItem();
func.Name = token.Text;
ParseItem(func, tokens);
newItem = func;
newItem.Priority = 0;
}
else
{
if (string.Compare(token.Text, "true", true) == 0)
{
// 布尔值常量
newItem = new DCConstExpressionItem(true, DCValueType.Boolean);
}
else if (string.Compare(token.Text, "false", true) == 0)
{
// 布尔值常量
newItem = new DCConstExpressionItem(false, DCValueType.Boolean);
}
else
{
double dbl = 0;
if (double.TryParse(token.Text, out dbl))
{
// 数字常量
newItem = new DCConstExpressionItem(dbl, DCValueType.Number);
}
else
{
// 引用的变量
DCVariableExpressionItem var = new DCVariableExpressionItem();
var.Name = token.Text;
newItem = var;
}
}
newItem.Priority = 0;
}
}
else if (token.Type == CharType.StringConst)
{
// 字符串常量
var strV = token.Text;
if (strV != null && strV.Length >= 2)
{
if (strV[0] == '\'' || strV[0] == '"')
{
strV = strV.Substring(1, strV.Length - 2);
}
}
newItem = new DCConstExpressionItem(strV, DCValueType.String);
}
else if (token.Type == CharType.CurLeft)
{
// 左圆括号，则进行分组
DCGroupExpressionItem group = new DCGroupExpressionItem();
newItem = group;
newItem.Priority = 0;
ParseItem(group, tokens);
}
else if (token.Type == CharType.Spliter ||
token.Type == CharType.CurRight)
{
// 分隔符号或者右圆括号则退出分组
if (items == null || items.Count == 0)
{
throw new System.Exception("项目分组无效:" + this.Text);
}
if (items != null && items.Count > 0)
{
DCExpressionItem item = CollpaseItems(items);
rootItem.AddSubItem(item);
}
items = new List <DCExpressionItem>();
if (token.Type == CharType.CurRight)
{
//退出分组
break;
}
else
{
continue;
}
}
else if (token.Type == CharType.MathOperator ||
token.Type == CharType.LogicOperator)
{
// 操作符号
DCOperatorExpressionItem math = new DCOperatorExpressionItem();
math.Text = token.Text;
switch (token.Text)
{
case "+":
math.Operator = DCOperatorType.Plus;
math.Priority = 1;
break;
case "-":
math.Operator = DCOperatorType.Minus;
math.Priority = 1;
break;
case "*":
math.Operator = DCOperatorType.Multi;
math.Priority = 2;
break;
case "/":
math.Operator = DCOperatorType.Division;
math.Priority = 2;
break;
case ">":
math.Operator = DCOperatorType.Bigger;
math.Priority = 0;
math.IsLogicExpression = true;
break;
case ">=":
math.Operator = DCOperatorType.BiggerOrEqual;
math.Priority = 0;
math.IsLogicExpression = true;
break;
case "=":
math.Operator = DCOperatorType.Equal;
math.Priority = 0;
math.IsLogicExpression = true;
break;
case "==":
math.Operator = DCOperatorType.Equal;
math.Priority = 0;
math.IsLogicExpression = true;
break;
case "<":
math.Operator = DCOperatorType.Less;
math.Priority = 0;
math.IsLogicExpression = true;
break;
case "<=":
math.Operator = DCOperatorType.LessOrEqual;
math.Priority = 0;
math.IsLogicExpression = true;
break;
case "%":
math.Operator = DCOperatorType.Mod;
math.Priority = 2;
break;
case "||":
math.Operator = DCOperatorType.Or;
math.Priority = -1;
math.IsLogicExpression = true;
break;
case "&&":
math.Operator = DCOperatorType.And;
math.Priority = -1;
math.IsLogicExpression = true;
break;
case "!=":
math.Operator = DCOperatorType.Unequal;
math.Priority = 0;
math.IsLogicExpression = true;
break;
default:
throw new NotSupportedException("无效操作符:" + token.Text);
}
newItem = math;
}
else
{
throw new NotSupportedException(token.Type + ":" + token.Text);
}
items.Add(newItem);
}//while
DCExpressionItem item2 = CollpaseItems(items);
if (item2 != null)
{
rootItem.AddSubItem(item2);
}
}