can in Re: ref, no, maybe?

This thread strongly reminds me of Readonly error on $_. In his response, merlyn displays some trick using the can method. /me thinks it can be applied here also. Saves the use of UNIVERSAL, but uses eval.

if eval( $r->can('can')) {
    #we have an object
} elsif ref( $r) {
    #we have an unblessed reference
} else {
    #no reference at all
}
[download]

Merlyn's solution looks somewhat cleaner to me. What do you think?

Jeroen
I was dreaming of guitarnotes that would irritate an executive kind of guy (FZ)

Comment on can in Re: ref, no, maybe? Download Code

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(tye)Re: can in Re: ref, no, maybe?
by tye (Sage) on Jan 11, 2001 at 19:35 UTC

I'd rewrite your code like this:

if(  ! ref($r)  ) {
    #no reference at all
} elsif(  ! eval { $r->can('can') }  ) {
    #unblessed ref
} else {
    #blessed ref
}
[download]

$r->can('can')

merlyn

version

"This is a test"->can('can')

As for the difference between eval { $r->can('can') } and eval { $r->isa('UNIVERSAL') }, the only advantage I see to the first is fewer keystrokes. I find the latter clearer, personally. But that gave me the idea for $r->can('isa'), which I find clear (as well as short). I guess isa() screams "object" to my brain faster than can() does, not sure why.

tye

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