Evaluated proc magic:resize {wand {x {}} {y {}}} { if {$y != "" && $x != ""} { @@$wand resize $x $y } elseif { $x != "" && $y == "" } { magic:scalex $wand $x; save $wand } elseif {$x == "" && $y != ""} { magic:scaley $wand $y; save $wand } else { error {you must supply a height or width} } }