How do I force a key to enter just one character when being pressed?

[DunbarX at aol.com]

I had tried a few methods in my last post. One line is not necessary. So 
this:

on keyDown var
    if the stillPressed of me = "true" then exit to top
    put var after me
    set the stillPressed of me to "true"
end keyDown

on keyup
   set the stillPressed of me to "false"
end keyup