regnames_count

Return the number of distinct named capture groups in the pattern of the most recent successful match.

The count is always the number of distinct names defined in the pattern — it does not depend on which names participated in the match, and it does not necessarily match the length of what regnames() returns when that is called without its $all argument.

Synopsis

use re 'regnames_count';
"abc" =~ /(?<a>x)|(?<b>b)/;
my $n = regnames_count();     # 2

What you get back

An integer count, or undef if there was no prior successful match in the current scope.

Examples

"foobar" =~ /(?<w>\w+)/;
print regnames_count();         # 1

"abc" =~ /(?<a>.)(?<b>.)(?<a>.)/;   # duplicate name 'a'
print regnames_count();         # 2 — counts distinct names

Edge cases

• No prior successful match — returns undef.

• Pattern has no named captures — returns 0.