Re^2: Named Captures

[BrowserUk]

Okay. What is going on here then?

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

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

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

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

[Corion]

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

/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

/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

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?

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.

[BrowserUk]

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

[JavaFan]

Not quite.

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

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