title: Nim-lang: list comprehension with two variables
body: <p>Confused on how to perform a list comprehension using two variables.</p>
  
  <p>Here's what i'm trying to do so far:</p>
  
  <pre><code>let profile_row = lc[profile[r][c] | ( r &lt;- 0..&lt;4, c &lt;- 0..&lt;k ), int]
  </code></pre>
  
  <p>Here's the error:</p>
  
  <pre><code>greedy_motif_ba2d.nim(22, 40) Error: type mismatch: got &lt;seq[int], float&gt;
  </code></pre>
  
  <p>How is this correctly done?</p>