Re: Variable interpolation of object methods

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Re^2: Variable interpolation of object methods by choroba (Cardinal) on Oct 30, 2010 at 23:22 UTC
Or, even more obscure: `print "'@{[$gene->display_id]}'\n";` [download]	[reply] [d/l]
Re^3: Variable interpolation of object methods by Anonymous Monk on Oct 30, 2010 at 23:37 UTC
Any chance of an explanation rather than ever increasing obscurity ? :-D	[reply]
Re^4: Variable interpolation of object methods by johngg (Canon) on Oct 31, 2010 at 00:45 UTC
I believe it works like this:- `$gene->display_id # Invoke the display_id # method of $gene object [ ] # construct anonymous array # around returned value(s) @{ } # dereference same " " # Interpolate into double- # quoted string` [download] although I'm sure others will correct me if I've got it wrong! Cheers, JohnGG	[reply] [d/l]
Re^4: Variable interpolation of object methods by ambrus (Abbot) on Oct 31, 2010 at 10:21 UTC
You can read an explanation of that secret operator in Perl Idioms Explained - ${\$obj->method} and @{[sort @list]}.	[reply]
Re^5: Variable interpolation of object methods by tod222 (Pilgrim) on Oct 31, 2010 at 16:00 UTC
Re^6: Variable interpolation of object methods by Anonymous Monk on Oct 31, 2010 at 23:25 UTC
Re^2: Variable interpolation of object methods by Anonymous Monk on Oct 30, 2010 at 23:18 UTC
Browseruk, can you explain why your deferencing method worked but mine didn't. I thought perl was deferencing the refernce for the gene object by using the -> notation. Whta exactly are you deferencing as the display_id method doesn't retrun a reference. thanks	[reply]
Re^3: Variable interpolation of object methods by Anonymous Monk on Oct 30, 2010 at 23:21 UTC
are you creating a reference to this variable `$gene->display_id` and then deferencing it straight away with `${ }` Why do you have to do this? Why doesnt perl perform variable interpolation of these types of things out of the box as it were?	[reply] [d/l] [select]
Re^4: Variable interpolation of object methods by BrowserUk (Patriarch) on Oct 30, 2010 at 23:55 UTC
When the interpolation has read `$gene`, it stops parsing and so never sees the dereference (->). Whereas, inside `${ ... }`, it expect any code, so it is parsed using the full Perl parser, rather than a limited parser looking only for a variable name. Note:That's my fits-the-evidence assumption, not definitive deep source-diving knowledge. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. RIP an inspiration; A true Folk's Guy	[reply] [d/l] [select]