Re^2: Is ": lvalue" attribute usefull or something to avoid?

It is possible to validate the values, it's just traditionally a pain in the arse, because it involves using something like Variable::Magic or returning a tied scalar.

I wrote LV to try to get around these issues, and it does indeed make writing lvalue subs pretty friendly. The primary drawback becomes speed - none of the implementations are as fast as a more traditionally written accessor.

use Moops; class Cow :rw { has name => (default => 'Ermintrude') }; say Cow->new->name

Comment on Re^2: Is ": lvalue" attribute usefull or something to avoid?

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Re^3: Is ": lvalue" attribute usefull or something to avoid? by BrowserUk (Patriarch) on Feb 12, 2014 at 14:16 UTC
It is possible to validate the values, it's just traditionally a pain in the arse, because it involves using something like Variable::Magic or returning a tied scalar. Yes. I've done it using a tied scalars, but the penalties -- not just performance, but the obfuscation factor -- makes it a complete non-starter IMO. none of the implementations are as fast as a more traditionally written accessor. If the performance penalty was a few percent, the syntactic sugar might be viable; but when it is closer 200% or 300% for subroutines/methods that already have a high overhead to work-done ratio, it simply isn't worth it. With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' 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.	[reply]
Re^4: Is ": lvalue" attribute usefull or something to avoid? by tobyink (Canon) on Feb 12, 2014 at 15:05 UTC
300%? In my experience it's often a lot more than that! That said, our old friend Class::XSAccessor to the rescue! If you're writing OO code, want lvalue accessors, and don't give a crap about validating incoming data, then its lvalue accessors are likely to be much faster than any pure Perl accessor you could write. (Not quite as fast as Class::XSAccessors non-lvalue accessors though.) Read more... (2 kB) `use Moops; class Cow :rw { has name => (default => 'Ermintrude') }; say Cow->new->name`	[reply] [d/l]