Nicolas Richard <youngf...@members.fsf.org> writes: > Rolf Ade <r...@pointsman.de> writes: >> (That is: >> http://mbork.pl/2016-05-23_Literal_values_and_destructive_functions) >> >> Wait, what? >> [...] >> in *Messages*. Could someone please explain that to me? > > The article you're referring to explains just that. Is it somehow > unclear ? Quoting the article: > > | What’s going on? > | > | Well, the literal in the function definition was actually changed. (If > | you evaluate the defun form now, it will be redefined once again to > | the “correct” value.) If you don’t believe it, try this: M-: > | (symbol-function #'destructive-havoc), or even better, M-x > | pp-eval-expression RET (symbol-function #'destructive-havoc) RET and > | see for yourself.
Well ..., sorry, yes, that explanation isn't clear to me. While I'm far away to claim I'm a versed emacs lisp programmer, I've written a few screen full of emacs lisp code. Now this thing left me back with the feeling, that I've missed to understand something at the core of the language (with the additional unpleasant feeling, that my emacs lisp programming is even more cargo cult coding, than I already suspected). The "explanation", that the literal in the function definition was changed by the (sort) call doesn't help me on track. While I'm fluent with other programming languages, that are able to rewrite function definitions during run-time I don't know a programming language that do this as a 'side effect' of a function call (other than you craft one, that deliberate does so). Is what the article demonstrates something special to the 'build-in' function sort or to emacs lisp? It would help me, if someone explains what happen in this example in other words (not in implementation detail but language concepts).
