Just to elucidate on merlyn's can method (no pun intended), the following works just fine:

$b = "foo";
$o->can($b . "_edit")->();
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bbfu
Seasons don't fear The Reaper.
Nor do the wind, the sun, and the rain.
We can be like they are.

If you call a method like a function, and in this case you do, you want to pass the object as the first argument. $o->can($b . "_edit")->($o); -Anomo