The function "grade up" has the symbol "<". The composition of this function with itself "<<" is not a special case- it's "grade up of grade up". Compositions o

The function "grade up" has the symbol "<". The composition of this function with itself "<<" is not a special case- it's "grade up of grade up". Compositions of functions are first-class objects in K, so you could certainly give it a name if you like (as well as eliding some of the brackets in the above example): ordinal: <<: (x,y,z)[ordinal g] "1a23z4z56b7c8d9" (x,y,z)ordinal g "1a23z4z56b7c8d9" The idiom << is common enough, though, that K programmers learn to recognize it when they see it in code. I'd have to look up the definition of "ordinal" to be certain it did what I think, but << is totally unambiguous. Contrary to your argument, naming short idioms like ,/ << +| and so on actually makes a program less explicit.