Trying to return a value (no pointer) to a generic type?

Getting Help
1

I have the following function which works:

package main

type CISettings interface {
	Clone() CISettings
	Merge(other CISettings)
}

type Settings struct{}

func (s *Settings) Clone() CISettings {
	return &Settings{}
}

func (s *Settings) Merge(other CISettings) {
}

func ParseCISettings[T CISettings](settings T) error {
	sett := settings.Clone()
	settings.Merge(sett)
	return nil
}

func main() {
	sett := Settings{}
	ParseCISettings[*Settings](&sett)
}

link

I have trouble finding out why a signature where I return the settings does not work:

ParseCISettings[T CISettings](settings T, err error)

link

I am not grocking what the compiler trys to tell me. If I make value receivers it works, but thats not how Merge should be implemented, it needs a pointer receiver.

2

This is a very simple interface problem, in your code implementation, it is ‘*Settings’ that implements ‘CISettings’, not ‘Settings’.

You can try calling it like this:

func main() {
	sett := Settings{}
	ParseCISettings(&sett)
}
3

You understood the question wrong:
I want to return a new type Settings not passing it in.

4

I don’t know what you’re trying to express, if you can, write some pseudocode.

5

I am still a little bit confused of you expected results, but maybe you are trying to do something like this:

?

6

It tells you that you cannot use Settings type as the interface, because this type does not implement this interface. The error is in main function here:

ParseCISettings[Settings]()

You implemented both methods Clone and Merge for pointer: *Settings!

func (s *Settings) Clone() CISettings {
	return &Settings{}
}

func (s *Settings) Merge(other CISettings) {}

You either need to change it to value itself or change the generic type you are passing in main:

ParseCISettings[*Settings]()
7

Thanks, thats close to what I want.
But what ever the parse function does I wanted to return a value Settings (or a pointer to it). But I dont know how to construct such a thing, cause var v T does not work. Or how do I construct a new value in a generic function using T as parameter?

8

Can you please be more specific on what exactly you are trying to achieve? What parameters the parsing function should have, what it will return, because now, I’m lost

9

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