Posted to tcl by aspect at Wed Jan 29 18:27:33 GMT 2014view pretty

proc main {{x 2}} {
    if {$x < 3} {
        set ::result "too small"
    } elseif {$x > 5} {
        set ::result "too high"
    }
}

trace add execution main leavestep {apply {{_ _ r _} {set ::result $r}}}
main 2
puts [set result]