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Re^2: Value of a statement with modifier

by LTjake (Prior)
on Jan 22, 2007 at 18:18 UTC ( #595959=note: print w/replies, xml ) Need Help??


in reply to Re: Value of a statement with modifier
in thread Value of a statement with modifier

A small quibble, but I believe the first example should be written as:

return $_[ 0 ] ? () : 'hello';

--
"Go up to the next female stranger you see and tell her that her "body is a wonderland."
My hypothesis is that she’ll be too busy laughing at you to even bother slapping you.
" (src)

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Re^3: Value of a statement with modifier
by hossman (Prior) on Jan 23, 2007 at 02:40 UTC

      Returning undef for false is more broken than returning empty lists for false. At least an empty list is easily promoted to a false or undef value but an undef value in a list is not as easily demoted to a false value. I think all the people returning undef for false are shortsighted and I hope they never get their hands on my code.

      sub empty {} if ( empty() ) { ... } # ok @foo = empty(); if ( @foo ) { ... } # ok sub returns_undef { undef } if ( returns_undef() ) { ... } # ok @foo = returns_undef(); if ( @foo ) { ... } # NOT OK if ( grep { defined } @foo ) { ... } # oh ok, now it's "better".

      ⠤⠤ ⠙⠊⠕⠞⠁⠇⠑⠧⠊

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[Corion]: ambrus: Yeah, I read that, but it's somewhat vague as in what I really have to implement, and where/how my "other" mainloop should/needs to call AnyEvent
[Corion]: (or maybe I just work better from existing code that I munge until it works and I understand it rather than a short abstract text like "implement everything that's needed" ;) )
[ambrus]: Corion: I think in this case you can get away with only a stub for idle, one that always dies when you create it, because AnyEvent::HTTP doesn't use it, not even indirectly through AnyEvent::Handle or AnyEvent::Socket or AnyEvent::DNS.
[Corion]: The "and I understand it" part is optional.
[Corion]: ambrus: Yes but I also need to implement the file / IO watcher, because Prima has that (in Prima::File), and I need to supply the appropriate thing to make push_write etc. work with Prima
[ambrus]: Corion: yes, you need to implement the io watcher, which should be simple because Prima::File is basically that, and the timer watcher form Prima::Timer
[Corion]: ... or so I think. As I said, I'm somewhat vague on how to make AnyEvent cooperate with a callback-driven IO event loop that gives me callbacks when data is available or can be written
[ambrus]: what push_write thing? I don't think you need that. that's implemented generically by AnyEvent::Handle
[Corion]: ambrus: Yeah, that's what I think as well. But you give me an idea, maybe I should start with implementing the timer, as that should be far simpler and with fewer edge-cases/nasty interaction than the file watcher
[ambrus]: You only provide the watcher part that tells when the handle is readable or writable, not the actual writing and reading.

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