title: Attempt to create nested for loops generating missing arguments error
body: <p>Am attempting to teach myself to program using Tcl. (I want to become more familiar with the language to understand someone else's code - SCID chess)
  The task i've set myself to motivate my learing of Tcl is to solve the 8 queens problem.
  My approach to creating a program is to sucessively 'prototype' a solution.
  So.
  I'm up to nesting a for loop holding the q pos on row 2 
     inside the for loop holding the q pos on row 1 </p>
  
  <p>Here is my code </p>
  
  <pre><code>set allowd 1
  set notallowd 0
  
  for {set r1p 1} {$r1p &lt;= 8} {incr r1p } {
      puts "1st row q placed at $r1p" 
      ;# re-initialize r2 'free for q placemnt' array after every change of r1 q pos:
      for {set i 1 } {$i &lt;= 8} {incr i} { set r2($i) $allowd    }
  
      for { set r2($r1p) $notallowd ; set r2([eval $r1p-1]) $notallowd ;
             set r2([eval $r1p+1]) $notallowd ; set r2p 1}   {$r2p &lt;= 8} {
           incr r2p ;# end of 'next' arg of r2 forloop
          }
          ;# commnd arg of r2 forloop placed below: 
          {puts "2nd row q placed at $r2p"    
      }
  } 
  </code></pre>
  
  <p>My problem is that when i run the code the interpreter is aborting with the fatal error:
  "wrong #args should be for start test next command.</p>
  
  <p>I've gone over my code a few times and can't see that i've missed any of the for loop arguments.</p>