erlang: Simple Debug macro

When testing things I need some quick way to debug "a la" printf() style. Old habits :)

Here's is the simple debug macro I use:

-ifdef(debug).
-define(DEBUG(Format, Args),
  io:format("~s.~w: DEBUG: " ++ Format, [ ?MODULE, ?LINE | Args])).
-else.
-define(DEBUG(Format, Args), true).
-endif.

Write it down in a "debug.hrl" file, then you only need to add this line in any file header:

-include("debug.hrl").

This simple macro gives you the module name and the line number. This saves me a lot of time.

Then you need to define the "debug" atom to let your macro do what you want. The compile:file/2 handles options for this, the syntax is {d, debug}

Quick Tip, list join

Another "lists:join" :

Join = fun([X|Rest], D) -> 
  [ X | [ [D,E] || E <- Rest ] ] 
  end.

Usage:

io:format("~s~n", [Join(["a", "b", "cde", "h", "k", "lm"], $,)]).
a,b,cde,h,k,lm
ok