Oh OK. $SUB is just a variable... same idea as $TUB or $PUB or $RUB... nothing special. In this case it's undefined, so when interpolated into the string doesn't do anything.

perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

In reply to Re^5: use of $sub by tobyink
in thread use of $sub by JimLS

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