in reply to Re^2: Reference assessment techniques and how they fail
in thread Reference assessment techniques and how they fail

Good point, but there's actually another problem I forgot to mention. In a &{}, undef is code.

That's not true. Why is your eval always returning 1 unless it dies? With 

sub is_code {
    no warnings qw( void uninitialized );
    return eval { defined &{$_[0]} };
}

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things look more reasonable. If undef were code, it'd be a serious bug.

--shmem 

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

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Re^4: Reference assessment techniques and how they fail
by kyle (Abbot) on Feb 17, 2008 at 19:50 UTC

    Ah, you're right. I was thinking of the wrong exception and wrote the wrong test. 

    use Test::More 'tests' => 5;

sub is_code {
    no warnings qw( void uninitialized );
    return eval { defined &{$_[0]} };
}

sub real_sub { die 'real sub called' }
my $sub_ref = sub { die 'sub ref called' };
my $undef;

ok( is_code( \&real_sub ), 'real sub ref is code' );
ok( is_code( $sub_ref   ), 'lexical sub ref is code' );
ok( ! is_code( $undef   ), 'undef is not code' );
ok( ! is_code( 'string' ), 'string is not code' );
ok( is_code( 'real_sub' ), 'string is code' );

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    So you still need an extra check in is_code. 

    sub is_code {
    no warnings qw( void uninitialized );
    return '' ne ref $_[0] && eval { defined &{$_[0]} };
}

    [download]

    That's fairly simple, but I think I still prefer the battery of ref, Scalar::Util::reftype, Scalar::Util::blessed and overload::Method.

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