/// <summary>
/// 初始化预定义运算符表达式。
/// </summary>
/// <param name="line">指定预定义运算符表达式所在位置的行数。</param>
/// <param name="col">指定预定义运算符表达式所在位置的列数。</param>
/// <param name="lhs">指定预定义运算符表达式的左侧值。</param>
/// <param name="op">指定预定义运算符表达式的运算符。</param>
/// <param name="rhs">指定预定义运算符表达式的右侧值。</param>
public BinaryExpression(int line, int col, Expression lhs, TokenKind op, Expression rhs)
: base(line, col)
{
_Lhs = lhs;
_Rhs = rhs;
_op = op;
}
/// <summary>
/// 初始化回调方法表达式。
/// </summary>
/// <param name="line">指定回调方法表达式所在位置的行数。</param>
/// <param name="col">指定回调方法表达式所在位置的列数。</param>
/// <param name="obj">指定回调方法表达式的回调对象。</param>
/// <param name="name">指定回调方法表达式的名称。</param>
/// <param name="args">指定回调方法表达式的参数列表。</param>
public MethodCall(int line, int col, Expression obj, string name, Expression[] args)
: base(line, col)
{
_Name = name;
_Args = args;
_Obj = obj;
}
/// <summary>
/// 添加字符串表达式的实例。
/// </summary>
/// <param name="exp">指定一个表达式。</param>
public void Add(Expression exp)
{
_Exps.Add(exp);
}
/// <summary>
/// 初始化字段访问表达式。
/// </summary>
/// <param name="line">指定字段访问表达式所在位置的行数。</param>
/// <param name="col">指定字段访问表达式所在位置的列数。</param>
/// <param name="exp">指定字段访问表达式的值。</param>
/// <param name="field">指定字段访问表达式的字段名。</param>
public FieldAccess(int line, int col, Expression exp, string field)
: base(line, col)
{
_Exp = exp;
_Field = field;
}
/// <summary>
/// 初始化数组访问表达式。
/// </summary>
/// <param name="line">指定数组访问表达式所在位置的行数。</param>
/// <param name="col">指定数组访问表达式所在位置的列数。</param>
/// <param name="exp">指定数组访问表达式的值。</param>
/// <param name="index">指定数组访问表达式的索引。</param>
public ArrayAccess(int line, int col, Expression exp, Expression index)
: base(line, col)
{
_Exp = exp;
_Index = index;
}
/// <summary>
/// 执行表达式，并返回执行结果。
/// </summary>
/// <param name="exp">指定一个表达式实例。</param>
/// <returns>object</returns>
public object EvalExpression(Expression exp)
{
_CurrentExpression = exp;
try
{
if (exp is StringLiteral)
return ((StringLiteral)exp).Content;
else if (exp is Name)
{
return GetValue(((Name)exp).id);
}
else if (exp is FieldAccess)
{
FieldAccess fa = (FieldAccess)exp;
object obj = this.EvalExpression(fa.Exp);
string propertyName = fa.Field;
return EvalProperty(obj, propertyName);
}
else if (exp is MethodCall)
{
MethodCall ma = (MethodCall)exp;
object obj = this.EvalExpression(ma.CallObject);
string methodName = ma.Name;
return EvalMethodCall(obj, methodName, EvalArguments(ma.Args));
}
else if (exp is IntLiteral)
return ((IntLiteral)exp).Value;
else if (exp is DoubleLiteral)
return ((DoubleLiteral)exp).Value;
else if (exp is FCall)
{
FCall fcall = (FCall)exp;
if (!_Functions.ContainsKey(fcall.Name))
{
string msg = string.Format("函数未定义：{0}", fcall.Name);
throw new TemplateRuntimeException(msg, exp.Line, exp.Col);
}
TemplateFunction func = _Functions[fcall.Name];
object[] values = EvalArguments(fcall.Args);
return func(values);
}
else if (exp is StringExpression)
{
StringExpression stringExp = (StringExpression)exp;
StringBuilder sb = new StringBuilder();
foreach (Expression ex in stringExp.Expressions)
sb.Append(this.EvalExpression(ex));
return sb.ToString();
}
else if (exp is BinaryExpression)
return EvalBinaryExpression(exp as BinaryExpression);
else if (exp is ArrayAccess)
return EvalArrayAccess(exp as ArrayAccess);
else
throw new TemplateRuntimeException("无效的表达式类型：" + exp.GetType().Name, exp.Line, exp.Col);
}
catch (TemplateRuntimeException ex)
{
this.DisplayError(ex);
return null;
}
catch (Exception ex)
{
this.DisplayError(new TemplateRuntimeException(ex.Message, _CurrentExpression.Line, _CurrentExpression.Col));
return null;
}
}
/// <summary>
/// 处理表达式。
/// </summary>
/// <param name="exp">指定一个表达式实例。</param>
protected void ProcessExpression(Expression exp)
{
object value = this.EvalExpression(exp);
this.WriteValue(value);
}
/// <summary>
/// 执行参数列表，并返回执行结果。
/// </summary>
/// <param name="args">包含参数列表的表达式。</param>
/// <returns>object[]</returns>
protected object[] EvalArguments(Expression[] args)
{
object[] values = new object[args.Length];
for (int i = 0; i < values.Length; i++)
values[i] = this.EvalExpression(args[i]);
return values;
}
/// <summary>
/// 初始化回调函数表达式。
/// </summary>
/// <param name="line">指定回调函数表达式所在位置的行数。</param>
/// <param name="col">指定回调函数表达式所在位置的列数。</param>
/// <param name="name">指定回调函数表达式的名称。</param>
/// <param name="args">指定回调函数表达式的参数列表。</param>
public FCall(int line, int col, string name, Expression[] args)
: base(line, col)
{
_Name = name;
_Args = args;
}