Richard Suchenwirth 2006-02-07 - For doing some OO sugar, I needed a way that interp aliases are cleaned up when the proc scope where they were defined is left. Here's my solution with a guard variable, to which an unset trace is tied:
proc alias {name = args} {
upvar 1 __$name __$name
eval [list interp alias {} $name {}] $args
set __$name ""
trace var __$name u "interp alias {} $name {} ;#"
}
proc test {} {
alias up = string toupper
return [up hello],[up world]
}
146 % test
HELLO,WORLD
277 % up this
invalid command name "up"