title: Why do I get unbound variable error in Scheme?
body: <pre><code>(define (even-odd x)
  (if ( ==(% x 2 ) 0) (1) (0)))
  </code></pre>
  
  <p>when i call( even-odd 5 )
   i get this message</p>
  
  <pre><code>;Unbound variable: %
  ;To continue, call RESTART with an option number:
  ; (RESTART 11) =&gt; Specify a value to use instead of %.
  ; (RESTART 10) =&gt; Define % to a given value.
  ; (RESTART 9) =&gt; Return to read-eval-print level 9.
  ; (RESTART 8) =&gt; Return to read-eval-print level 8.
  ; (RESTART 7) =&gt; Return to read-eval-print level 7.
  ; (RESTART 6) =&gt; Return to read-eval-print level 6.
  ; (RESTART 5) =&gt; Return to read-eval-print level 5.
  ; (RESTART 4) =&gt; Return to read-eval-print level 4.
  ; (RESTART 3) =&gt; Return to read-eval-print level 3.
  ; (RESTART 2) =&gt; Return to read-eval-print level 2.
  ; (RESTART 1) =&gt; Return to read-eval-print level 1.
  </code></pre>
  
  <p>;Start debugger? (y or n): </p>
  
  <p>Am i doing something wrong ?Also let me know how to select text in edwin.</p>