Should macro_module_names allow for ?FUNCTION_NAME?

[paulo-ferraz-oliveira]

We seem to allow for ?MODULE already, so ?FUNCTION_NAME seems kinda controlled to. Useful in generic definition modules, for example.

get() ->
  ...,
  stats(?FUNCTION_NAME),
  ....

put() ->
  ...,
  stats(?FUNCTION_NAME),
  ....

post() ->
  ...,
  stats(?FUNCTION_NAME),
  ....

stats(get) ->
  ...;
stats(put) ->
  ...;
stats(post) ->
  ....

Oh, and, of course, your favorite, Brujo, would be using it in a macro. (⚠️ high readability/maintainability ahead)

-define(STATS, stats(?FUNCTION_NAME)).

get() ->
  ...,
  ?STATS(),
  ....

put() ->
  ...,
  ?STATS(),
  ....

post() ->
  ...,
  ?STATS(),
  ....

stats(get) ->
  ...;
stats(put) ->
  ...;
stats(post) ->
  ....

😄

We have no_macros, but that one seems to avoid ?MODULE and ?FUNCTION_NAME already.

[elbrujohalcon]

But nothing in your code uses ?FUNCTION_NAME in a dynamic call, right?

🤨

[elbrujohalcon]

I mean… what's the argument for writing ?FUNCTION_NAME (14 characters, in upper case, and including a ?) instead of log 🤨

[paulo-ferraz-oliveira]

It's a smaller example in a larger extensible way of writing. But you're right, maybe not worth the effort, as error prone.

In any case, macro_module_names is mis-named, I guess, since it also looks at function names in the dynamic call. But that's a different issue.

[paulo-ferraz-oliveira]

Code like Logger:?FUNCTION_NAME(Msg) is precisely what this rule is trying to prevent.

I mean, sure, but ?FUNCTION_NAME is pretty well defined in terms of scope, unlike some other random macro the developer defines somewhere. You can argue, for example, that moving that code to another function would change its behaviour, but that argument would apply similarly to ?MODULE.

[elbrujohalcon]

Yeah, but ?MODULE:a_function(…) will have the effect of that function using the new version of it if the module is re-compiled/re-loaded. In other words, it's a common practice used in conjunction with hot-code reloading. Not my favorite paradigm (I would happily write the module name there) but at least a well-known one that is somewhat intuitive to whoever is reading.

[paulo-ferraz-oliveira]

I saw your update on the documentation. Rationale's are always good to have.