GPS Oct 16, 2003 - Today it occured to me that I might accidentally set the wrong variable in my Perpheon language translator, and it could cause me to have a nasty debug session, so I decided to come up with a proc that sets a variable but returns an error if it doesn't exist.
proc ?set {vPtr val} {
upvar $vPtr v
if {![info exists v]} {
return -code error "error: variable doesn't exist."
}
set v $val
}Here is a log demonstrating usage:
% ?set foo bar error: variable doesn't exist. % set foo abc abc % ?set foo bar bar % set foo bar %