Go makes composition less powerful than it could be by slicing structs, which means a lot of hoop jumping to get template methods (where blanks are filled in downstream).

I've been playing around with first class environments [0] lately in g-fu [1], which allow convenient and flexible composition of data and behavior using only what was already there.

I have a feeling Lua might be playing similar tricks with its tables, but I lack enough experience to judge.

[0] https://github.com/codr7/g-fu/blob/master/v1/lib/eos.gf

[1] https://github.com/codr7/g-fu