How can I determine if an object or reference has a valid string coercion?
- by Ether
I've run into a situation (while logging various data changes) where I need to determine if a reference has a valid string coercion (e.g. can properly be printed into a log or stored in a database). There isn't anything in Scalar::Util to do this, so I have cobbled together something using other methods in that library:
use strict;
use warnings;
use Scalar::Util qw(reftype refaddr);
sub has_string_coercion
{
my $value = shift;
my $as_string = "$value";
my $ref = ref $value;
my $reftype = reftype $value;
my $refaddr = sprintf "0x%x", refaddr $value;
if ($ref eq $reftype)
{
# base-type references stringify as REF(0xADDR)
return $as_string !~ /^${ref}\(${refaddr}\)$/;
}
else
{
# blessed objects stringify as REF=REFTYPE(0xADDR)
return $as_string !~ /^${ref}=${reftype}\(${refaddr}\)$/;
}
}
# Example:
use DateTime;
my $ref1 = DateTime->now;
my $ref2 = \'foo';
print "DateTime has coercion: " . has_string_coercion($ref1) . "\n\n";
print "scalar ref has coercion: " . has_string_coercion($ref2) . "\n";
However, I suspect there might be a better way of determining this by inspecting the guts of the variable in some way. How can this be done better?
