public void MapParameter(ParameterInfo pi) {
int indexForArgBuilder;
int nameIndex = _argNames.IndexOf(pi.Name);
if (nameIndex == -1) {
// positional argument, we simply consume the next argument
indexForArgBuilder = _argIndex++;
} else {
// keyword argument, we just tell the simple arg builder to consume arg 0.
// KeywordArgBuilder will then pass in the correct single argument based
// upon the actual argument number provided by the user.
indexForArgBuilder = 0;
}
// if the parameter is default we need to build a default arg builder and then
// build a reduced method at the end.
if (!pi.IsMandatory()) {
// We need to build the default builder even if we have a parameter for it already to
// get good consistency of our error messages. But consider a method like
// def foo(a=1, b=2) and the user calls it as foo(b=3). Then adding the default
// value breaks an otherwise valid call. This is because we only generate MethodCandidates
// filling in the defaults from right to left (so the method - 1 arg requires a,
// and the method minus 2 args requires b). So we only add the default if it's
// a positional arg or we don't already have a default value.
if (nameIndex == -1 || !_hasDefaults) {
_defaultArguments.Add(new DefaultArgBuilder(pi));
_hasDefaults = true;
} else {
_defaultArguments.Add(null);
}
} else if (_defaultArguments.Count > 0) {
// non-contigious default parameter
_defaultArguments.Add(null);
}
ArgBuilder ab;
if (pi.ParameterType.IsByRef) {
_hasByRef = true;
Type refType = typeof(StrongBox<>).MakeGenericType(pi.ParameterType.GetElementType());
_parameters.Add(new ParameterWrapper(pi, refType, pi.Name, ParameterBindingFlags.ProhibitNull));
ab = new ReferenceArgBuilder(pi, refType, indexForArgBuilder);
} else if (pi.Position == 0 && _overload.IsExtension) {
_parameters.Add(new ParameterWrapper(pi, pi.ParameterType, pi.Name, ParameterBindingFlags.IsHidden));
ab = new SimpleArgBuilder(pi.ParameterType, indexForArgBuilder, false, false);
} else {
ab = AddSimpleParameterMapping(pi, indexForArgBuilder);
}
if (nameIndex == -1) {
_arguments.Add(ab);
} else {
Debug.Assert(KeywordArgBuilder.BuilderExpectsSingleParameter(ab));
_arguments.Add(new KeywordArgBuilder(ab, _argNames.Count, nameIndex));
}
}