private static bool TryParseFunctionDeclaration(IdentifierNode identifier, ArgumentSetNode argumentSet, [NotNullWhen(true)] out FunctionDeclaration?declaration)
{
declaration = default;
var functionName = identifier.TextValue;
var arguments = argumentSet.Arguments.Select(ParseParameterDeclaration).ToArray();
// Check for a required parameter that exists after an optional parameter
var firstOptionalIndex = int.MaxValue;
for (int argIndex = 0; argIndex < arguments.Length; ++argIndex)
{
var arg = arguments[argIndex] ?? throw new NotImplementedException();
if (arg.Optional)
{
firstOptionalIndex = Math.Min(firstOptionalIndex, argIndex);
}
else if (firstOptionalIndex != int.MaxValue)
{
// This is *NOT* optional, yet exists after an optional parameter.
throw new NotImplementedException();
}
}
ParameterDeclaration[] nonNullArguments = arguments.Where(arg => arg != null).Select(arg => arg).ToArray() !;
if (nonNullArguments.Length != arguments.Length)
{
return(false);
}
declaration = new FunctionDeclaration(returnType: typeof(object), functionName, nonNullArguments);
return(true);
}
public object?Transform(ArgumentSetNode item)
{
throw new NotImplementedException();
}
public IEnumerable <bool> Transform(ArgumentSetNode item)
{
yield return(false);
}
