What does the “head mismatch” compiler error mean?

Question

I tries to write code to print Z character.

zzzzzzz
     z
    z
   z
  z
 z
zzzzzzz

But when I compile this code, it throws

D         


        

Answer 1

the problem is that you have mixed up 2 functions:

zeez/2 and zeez/3

If you terminate the zeez/3 function by ending it with a full stop not a semi-colon it should compile:

zeez(true, M, N) ->
    io:format("~p~n", [zeez(space, N-M)] ), % line 16
    zeez(M rem N =:= 0, M + 1 , N );                      <-- should end with .

The error message means, 'hey I'm in zeez/3 and you have thrown in a 2-arity clause, wtf?'