[Help] Translating from LinqKit Invoke + Expand to NeinLinq

[SpaceOgre]

Hi, please feel free to close this if you feel I should ask this somewhere else.

Today I'm using LinqKit to be able to reuse some Expression for selecting from collections, but I would like if I could only use NeinLinq since I want the Apply feature of it. I have tried for a long time now, but I can't figure out how to translate this to NeinLinq:

Base expression that should be reused:

    internal static class MapperForDTO
    {
        internal static Expression<Func<Subject, EducationEvent, PeriodData, MyStudentsListDTO>> ToDTO =>
            (subject, educationEvent, _) => new MyStudentsListDTO
            {
                Id = subject.Id,
                School Name = educationEvent.Name,
                //more stuff here
            };
    }

Code to use it for the specified entity:

Expression<Func<EducationEvent, MyStudentsListDTO>> mapper =
    educationEvent => MapperForDTO.ToDTO.Invoke(educationEvent.Subject, educationEvent, null);
var selectExpression = mapper.Expand();

Code for the second entity using the same base expression:

Expression<Func<PeriodData, MyStudentsListDTO>> mapper =
    periodData => MapperForDTO.ToDTO.Invoke(periodData.Subject, periodData.EducationEvent, periodData);
var selectExpression = mapper.Expand();

It might be that I'm just thinking about this the wrong way but any help would be appreciated.

[axelheer]

You could apply “Lambda Injection” to your MapperForDTO and use ToDTO directly within your queries.

If you need the “expanded” selectExpression outside your query, you could use the InjectLambdaVisitor somehow directly or play with the various Apply methods.

I can play with it, but I’m on the road right now.