Sorry, I meant withArgs -- setArgs is internal. But instead of resetting, how about making setting the args the whole function of the new command, so then they can run main (or anything else) several times with the same argument?
This is mainly motivated by my recent development work - I kept ending up with a function called main2 which is called by main with the arguments, so I could develop it more easily. A :main removes this need, if only :args was available then it would require twice as many commands, i.e. :args blah, main, if you were continually changing the arguments. Also, this way main more closely models the Clean approach, where command line arguments are passed into main, not in a monad. However, having :args as well might be quite handy.
(I'm not sure what WinHugs interface you had in mind.) Currently the run button when the user has typed no expression runs 'main', I intend to change this to ':main'
Thanks Neil