title: Concatenate two atoms in prolog without using atom_concat
body: <p>I want to write prolog that can essentially do what this is doing</p>
  
  <pre><code>atom_concat('3',' =',Answer).
  Answer = '3 ='.
  </code></pre>
  
  <p>But I do not want to use the atom_concat function (or any built in predicates). I would also like the answer to have no quotation marks in it.</p>
  
  <p>I have tried implementing a method that operates the same as the append method, which I have called merge.</p>
  
  <pre><code>merge([],Xs,Xs).
  merge([X|Xs],Ys,[X|Zs]):-
      merge(Xs,Ys,Zs).
  </code></pre>
  
  <p>But when I write this into my db.pl file I get false when running it.</p>
  
  <pre><code>?- [db].
  true.
  
  ?- merge('3',' =',Answer).
  false.
  </code></pre>