perl -wE"'abcde' =~ m[(?<a>a)|(?<b>b)|(?<c>c)|(?<d>d)|(?<e>e)]g and do
+{ say for keys %+ }"
a
[download]

/g in scalar context matches once, %+ contains the first value, a.

perl -wE"()='abcde' =~ m[(?<a>a)|(?<b>b)|(?<c>c)|(?<d>d)|(?<e>e)]g and
+ do{ say for keys %+ }"
e
[download]

/g in list context matches all locations, and after having matched all, %+ contains the result of the last match, e.

perl -wE"my@a = 'abcde' =~ m[(?<a>a)|(?<b>b)|(?<c>c)|(?<d>d)|(?<e>e)]g
+ and do{ say for keys %+ }"
e
[download]

Same as above, except that you store the intermediate values.

perl -wE"my@a = 'abcde' =~ m[(?<a>a)|(?<b>b)|(?<c>c)]g and do{ say for
+ keys %+ }"
## big fat nothing?
[download]

You have removed [de] from the matching class. %+ is a global variable and it (seems it) is cleared by the last failing match.

It might or might not be nice to have %+ retain the value(s) of the last successful match, but maybe you can work around this by padding your RE with .*$re.* to convert it into a truely floating RE.

Okay. That begins to make sense ;)

But, I discovered that I can get (sort of) what I was after by switching to %-

perl -wE"()='abcde' =~ m[(?<a>a)|(?<b>b)|(?<c>c)|(?<d>d)|(?<e>e)]g and
+ do{ say for keys %- }"
e
c
a
b
d
[download]

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

RIP an inspiration; A true Folk's Guy

Not quite.

() = 'abc' =~ /(?<a>a)|(?<f>f)/ and do {say for keys %-};
__END__
a
f
[download]

%- will have a key for every named capture in the pattern, whether that capture was involved in the match or not.