$ perl -MO=Deparse,-p -e '($s,$m,$h,$md,$mo,$y,$w,$g,$i)=localtime;pri
+nt $y+1900 . "." . ($mo+1) . ".$md." . ($h-5) . "$m\n";'
(($s, $m, $h, $md, $mo, $y, $w, $g, $i) = (localtime));
print((((((($y + 1900) . '.') . ($mo + 1)) . ".$md.") . ($h - 5)) . "$
+m\n"));

$ perl -MO=Deparse,-p -e '($s,$m,$h,$md,$mo,$y,$w,$g,$i)=localtime;pri
+nt $y+1900 . "." . $mo+1 . ".$md." . ($h-5) . "$m\n";'
(($s, $m, $h, $md, $mo, $y, $w, $g, $i) = (localtime));
print(((((((($y + 1900) . '.') . $mo) + 1) . ".$md.") . ($h - 5)) . "$
+m\n"));
[download]

I knew it had to be precedence, but was unsure what it really looked like. The B::Deparse showed it beautifully. I will have to remember that one.

Tangential, but you might look at POSIX and strftime or something like DateTime::Format rather than monkeying with reimplementing wheels.

As to your question you can see how the precedence changes omitting the parens plays out if you stick -MO=Deparse,-p before the -e.

Update: Yeah, what he said below.

POSIX and strftime

I'd suggest Time::Piece instead, it's been a core module since 5.10.

<update>

$ perl -MTime::Piece -le 'print localtime->strftime("%Y.%m.%d.%H%M")'
2019.08.01.2239
[download]

</update>

DateTime::Format

Note that link goes to a defunct module, you probably meant the DateTime::Format::* family of modules instead. But plain DateTime has both strftime and CLDR formatting built right in, that's generally been enough for me (I usually parse with DateTime::Format::Strptime).