The only reliable way I know is to look for regexp magic on the SV:

$ perl -MDevel::Peek
my $r = qr/foo/;
my $n = 'bar';
Dump( $r );
Dump( $n );

SV = RV(0x817fb18) at 0x8152cdc
  REFCNT = 1
  FLAGS = (PADBUSY,PADMY,ROK)
  RV = 0x81535dc
  SV = PVMG(0x816dac8) at 0x81535dc
    REFCNT = 1
    FLAGS = (OBJECT,SMG)
    IV = 0
    NV = 0
    PV = 0
    MAGIC = 0x817c1f8
      MG_VIRTUAL = 0x814ee88
      MG_TYPE = PERL_MAGIC_qr(r)
      MG_OBJ = 0x8175270
    STASH = 0x81530f0   "Regexp"
SV = PV(0x8153b00) at 0x815360c
  REFCNT = 1
  FLAGS = (PADBUSY,PADMY,POK,pPOK)
  PV = 0x816ba88 "bar"\0
  CUR = 3
  LEN = 4

[download]

Unfortunately, I don't have an easy way to do that from pure-Perl code. I've also never had the need to do so.

In reply to Re: How can I tell if an object is based on a regex? by chromatic
in thread How can I tell if an object is based on a regex? by kyle

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