public Expression SubStringMethod(SubStringMethod method, LiteralExpression[] arguments)
{
if (arguments[0].LiteralType == LiteralType.Null)
{
return(arguments[0]);
}
else
{
int startIndex;
int length;
string result;
if (!LiteralUtil.TryCoerceInt(arguments[1], out startIndex))
{
throw new ODataException(String.Format(
ErrorMessages.Method_InvalidArgumentType,
method.MethodType, 2, "Edm.Int32"
));
}
if (arguments.Length == 3)
{
if (!LiteralUtil.TryCoerceInt(arguments[2], out length))
{
throw new ODataException(String.Format(
ErrorMessages.Method_InvalidArgumentType,
method.MethodType, 3, "Edm.Int32"
));
}
result = LiteralUtil.CoerceString(arguments[0]).Substring(startIndex - 1, length);
}
else
{
result = LiteralUtil.CoerceString(arguments[0]).Substring(startIndex - 1);
}
return(new LiteralExpression(result, LiteralType.String));
}
}
