title: How to force expr to address a value as a string and not a number?
body: <p>When TCL gets a string that starts with a <code>0</code> as its return value, it'll treat it as an octal number and will return the decimal value of the octal number. Is there a way to circumvent it and force <code>expr</code> to address the value as a string?</p>
  
  <p>I encounter this problem because I have a line:</p>
  
  <pre><code>set val [expr {( $obj == "" ) ? "" : [$obj data]}]
  </code></pre>
  
  <p>And one the results of the <code>[$obj data]</code> operation is a binary string starting with 0, and the <code>expr</code> turns it into another number. Is there a way to fix this without turning the <code>expr</code> into an <code>if</code>?</p>