[George Peter Staplin]: July 10, 2004 - It sometimes amazes me how beautiful some aspects of Tcl are.  I've been using proc unknown args {expr $args} for a while for doing calculations and tests when designing software.  Today it occured to me that I could make life easier and avoid so many parentheses by extending that simple unknown procedure to this:

 proc unknown args {set ::that [expr $args]}

Now I can do:

 $ echo "proc unknown args {set ::that [expr \$args]}" > .tclshrc
 $ tclsh8.4 
 % 1000 * 256
 256000
 % $that / 8
 32000

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[Scott Nichols] Really cool. Would there be any issues adding your calculator proc to existing Tcl applications? This would be helpful and save typing time for programmers.

[George Peter Staplin]: Error handling and auto-loading/lazy-loading might not work the same.  You could do it this way: 

 rename unknown _unknown
 proc unknown args {
  global that
  if {[catch {expr $args} that]} {
   uplevel 1 [concat _unknown $args]
  }
 }