You may know that Tcl can do this:

set a 2; set b 5
return [expr {$a<$b ? 1 : 0}]

It returns 1 when $a<$b, otherwise 0. But did you know that this works as well:

return [expr {$a<$b ? -1 : $a>$b ? 1 : 0}]

It will return -1 when $a<$b, 1 when $a>$b, else 0!