title: Argument expansion with format command
body: <p>I came across a scenario, where I need to use the argument expansion with <code>format</code> command. With Tcl8.5, I am using <code>{*}</code> and it works like charm. </p>
  
  <p>But, with Tcl8.4, i have tried <code>eval</code>. But, no luck. </p>
  
  <pre><code>% set x "This is stackoverflow"
  This is stackoverflow
  % format "%10s %5s %20s" {*}$x
        This    is        stackoverflow
  % eval format "%10s %5s %20s" $x
     %5s
  % eval list format "%10s %5s %20s" $x
  format %10s %5s %20s This is stackoverflow
  % eval [list format "%10s %5s %20s" $x]
  not enough arguments for all format specifiers
  % eval format "%10s %5s %20s" [list $x]
         %5s
  % eval format "%10s %5s %20s" [concat $x]
         %5s
  </code></pre>
  
  <p>What is my mistake here ? </p>