Are explicitly typed regexes allowed as keys in a Perl YAML dump?

Question

This relates to the previous question: How can I read Perl data structures from Python? ... It might be a bug in the version of the YAML parser I'm working with (0.66), but when I run:

perl -MYAML -le 'do shift; print YAML::Dump( $CPAN::Config )' simple.pl

In the following simple.pl

:

%config = (
    'color' => 'red',
    'numbers' => [5, 8],
    qr/^spam/ => qr/eggs$/,
);

I get:

---
(?-xism:^spam): !!perl/regexp (?-xism:eggs$)
color: red
numbers:
  - 5
  - 8

Note that the key regex is not explicitly typed. What gives? (Thank!)

+1

cdleary 06 jan. '09 at 7:55

1 answer

mirod · Accepted Answer · 2009-01-06T12:48:45+0000

From man perldata

:

Hashes are unordered collections of scalar values, indexed by their associated string key ...

Keys don't have a type in the YAML dump because they don't have a Perl type. They're just strings. In this case, the line(?-xism:^spam)

Try the following: perl -l -e'%config = ( qr/^spam/ => qr/eggs$/); print $config{"(?-xism:^spam)"}'