http://www.perlmonks.org?node_id=1029739


in reply to string on right side of m//?

It's deeply ingrained in Perl that the operators dictate what to do, and not the type of the operands (with few exceptions).

So =~ always does a regex match. If the right-hand side isn't a regex, it becomes one.

Same with . (coerces the arguments to be strings), + (coerces to numeric) etc.

Update: since the question was about documentation, I checked perlop if this was explained somewhere. I didn't find anything, so I've submitted a patch which adds such an explanation.