protected virtual Expression <T> Unary(IEnumerator <Token> tokens, IDictionary <string, VariableExpression <T> > variables)
{
tokens.MoveNext();
switch (tokens.Current.TokenType)
{
case TokenType.Scalar:
ScalarExpression <T> subExpr = ParseScalarValue(tokens.Current.Value);
tokens.MoveNext();
return(subExpr);
case TokenType.Identifier:
string identifierName = tokens.Current.Value;
tokens.MoveNext();
ConstantExpression <T> consExpr = ConstantFactory.CreateConstant(identifierName);
if (consExpr != null)
{
return(consExpr);
}
VariableExpression <T> varExpr = null;
if (!variables.TryGetValue(identifierName, out varExpr))
{
varExpr = new VariableExpression <T>(identifierName);
variables.Add(identifierName, varExpr);
}
return(varExpr);
case TokenType.Operator:
Func <IEnumerator <Token>, IDictionary <string, VariableExpression <T> >, Expression <T> > func;
if (UnaryOperatorHandlers.TryGetValue(tokens.Current.Value, out func))
{
return(func(tokens, variables));
}
else
{
throw new SyntaxException(String.Format("Incorrect operator \"{0}\".", tokens.Current.Value));
}
case TokenType.Function:
string funcName = tokens.Current.Value;
IList <Expression <T> > args = new List <Expression <T> >();
tokens.MoveNext();
if (tokens.Current.Value != "(")
{
throw ThrowExpectedException("(");
}
args.Add(AddSub(tokens, variables));
while (tokens.Current.Value != ")" && tokens.Current.Value == ",")
{
args.Add(AddSub(tokens, variables));
}
if (tokens.Current.Value != ")")
{
throw ThrowExpectedException(")");
}
tokens.MoveNext();
return(FunctionFactory.CreateFunction(funcName, args.ToArray()));
default:
throw new SyntaxException();
}
}
