In my project I have many collection (slices) of different data types. Any particular collection should define fields it can sort by. I want to write one sort function and call it with user input (sort field and order) whenever collection should be sorted. I came up with the following boilerplate code (described only one type of collection, but for others it will be the same): https://gist.github.com/abonec/f1ee23a38e78ea48d470c39885de47ba
I have an interface Sortable for collections. Sortable should be passed to the sortStats with user input of sort field. If concrete implementation supports this type of sort it should return sort.Interface with corresponding interface.
Problem with many repeated implementations of sort.Interface where Len() and Swap() method is identical. Different is only Less().
Is there any approach to get a rid of Len() and Swap() methods in this case or may be other approach to write generic sort function with dynamic sort field?
You're looking for generics, which Go doesn't currently support. See this FAQ entry.
The Go team is working to add generics to the language - it's a work in progress, and everyone is free to participate in the discussion. Once generics exist, they will provide the solution you seek here.
In the meantime, you could use code generation or think of a slightly different design for your problem. Some code duplication is OK too, Go doesn't frown upon it as badly as some other languages.