Thank you. Very informative.

YAML seems ok in this case:

 ysh -r
Welcome to the YAML Test Shell. Type ':help' for more information.

ysh > $a = { type => 'int' };
--- #YAML:1.0
type: int
ysh > $b = \$a->{type};
--- #YAML:1.0 !perl/ref:
=: int
ysh > [$b,$a]
--- #YAML:1.0
- !perl/ref:
  =: int
- type: !perl/ref:
    =: int
ysh > $$b={hi=>'there'}
--- #YAML:1.0
hi: there
ysh > [$b,$a]
--- #YAML:1.0
- !perl/ref:
  =: &1
    hi: there
- type: *1
[download]

Update: I'm not so sure. That !perl/ref: disappears
Ah. Perhaps b/c a hash is assumed to be a reference in YAML.