From: Etienne Vallette d'Osia <etienne.vallettedosia@...>
Date: 2010-10-08T17:21:46+09:00
Subject: [ruby-core:32719] Re: [Ruby 1.9-Feature#3845][Open] "in" infix operator

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Hi,

On Fri, Oct 8, 2010 at 9:16 AM, "Martin J. D=FCrst" <duerst@it.aoyama.ac.jp=
>wrote:

> I would understand that if it were [a, b, c].included? x
> But it's include?, so the order seems just fine. Easy to read as
> "does [a, b, c] include x?". Any other order would feel strange, wouldn't
> it?
>
> Also, an 'in?' method on Object has been proposed, so that you can write
> x.in? [a, b, c]
> That's very short, and fully object oriented pure Ruby, no syntactic suga=
r
> necessary.


I totally agree : in as keyword is too different than the rest of Ruby
syntax.
I fear this kind of add would make Ruby syntax cryptic...


>
>    3) it is inefficient; new array object is created every times
>>
>
> That's a problem for a good compiler/interpreter. There are many cases in
> Ruby where similar stuff happen, and nevertheless, many people are using
> Ruby. If it really needs to be fast, why not use C or so?
>
>
What about
  x.in?(a, b, c)

The Ruby naive implementation is really simple
  class Object
    def in?(*collections)
      collections.any?{|c| c.include?(self) }
    end
  end
but I guess a C version could add optimizations (but are they needed ?)


Regards,

=C9tienne


--=20
=C9tienne Vallette d'Osia

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Hi,<br><br><div class=3D"gmail_quote">On Fri, Oct 8, 2010 at 9:16 AM, &quot=
;Martin J. D=FCrst&quot; <span dir=3D"ltr">&lt;<a href=3D"mailto:duerst@it.=
aoyama.ac.jp">duerst@it.aoyama.ac.jp</a>&gt;</span> wrote:<br><blockquote c=
lass=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;=
padding-left:1ex;">


I would understand that if it were [a, b, c].included? x<br>
But it&#39;s include?, so the order seems just fine. Easy to read as<br>
&quot;does [a, b, c] include x?&quot;. Any other order would feel strange, =
wouldn&#39;t it?<br>
<br>
Also, an &#39;in?&#39; method on Object has been proposed, so that you can =
write<br>
<a href=3D"http://x.in/" target=3D"_blank">x.in</a>? [a, b, c]<br>
That&#39;s very short, and fully object oriented pure Ruby, no syntactic su=
gar necessary.</blockquote><div><br>I totally agree : in as keyword is too =
different than the rest of Ruby syntax.<br>I fear this kind of add would ma=
ke Ruby syntax cryptic...<br>

=A0</div><blockquote class=3D"gmail_quote" style=3D"margin: 0pt 0pt 0pt 0.8=
ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div cla=
ss=3D"im">
<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">
 =A0 3) it is inefficient; new array object is created every times<br>
</blockquote>
<br></div></blockquote><blockquote class=3D"gmail_quote" style=3D"margin: 0=
pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: =
1ex;">
That&#39;s a problem for a good compiler/interpreter. There are many cases =
in Ruby where similar stuff happen, and nevertheless, many people are using=
 Ruby. If it really needs to be fast, why not use C or so?<div class=3D"im"=
>

<br></div></blockquote><div><br>What about <br>=A0 <a href=3D"http://x.in?(=
a">x.in?(a</a>, b, c)<br><br>The Ruby naive implementation is really simple=
<br>=A0 class Object<br>=A0=A0=A0 def in?(*collections)<br>=A0=A0=A0=A0=A0 =
collections.any?{|c| c.include?(self) }<br>

=A0=A0=A0 end<br>=A0 end<br></div>
</div>but I guess a C version could add optimizations (but are they needed =
?)<br><br><br>Regards,<br><br>=C9tienne<br><br><br>-- <br>=C9tienne Vallett=
e d&#39;Osia<br>

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