Well yeah, referring to my above comment the primitives are symbols and it's expected that the user knows them, just as you're supposed to know the keywords in

Well yeah, referring to my above comment the primitives are symbols and it's expected that the user knows them, just as you're supposed to know the keywords in any language. Good (professional) APL though, will intersperse those primitives with meaningful variable names. Whether one thinks it's worth the effort to know the symbols vs know the keywords is matter of opinion. But if one dares calling oneself let's say a python programmer, I'd argue that anybody would expect that you'd know the keywords anyways.