See also while...wend in Tcl
There is a difference between do..until and whild..wend. By do..until the statment is executeted at least once
We can simulate such behaviour in Tcl by:
while 1 {
# ..statement
if {!expresion} break
}DKF: Try this:
proc do {body keyword expression} {
if {$keyword eq "while"} {
set expression "!($expression)"
} elseif {$keyword ne "until"} {
return -code error "unknown keyword \"$keyword\": must be until or while"
}
set condition [list expr $expression]
while 1 {
uplevel 1 $body
if {[uplevel 1 $condition]} {
break
}
}
return
}