I use this proc to parse a proc's args and allow any parameter to be
specified as a switch.  

To redefine proc so that all procs are "procargs" enabled:

   procargs proc

To "procargs" enable an existing proc

   procargs existingprocname 

To define a proc with "procargs" enabeled

   procargs proc { args } { body }

I also use it as a replacement for getopt and friends.  I write the 
main function of the scripted command as a proc and then eval that 
proc at the bottom of the file with $argv.

procargs main { parameter list here } {
	...
}

eval main $argv