From: Rodrigo Rosenfeld Rosas <rr.rosas@...>
Date: 2013-04-09T00:54:54+09:00
Subject: [ruby-core:54111] Re: [ruby-trunk - Feature #8237][Open] Logical method chaining via inferred receiver
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Em 08-04-2013 11:50, Trans escreveu:
> There are at least three other ways to approach this:
>
> user.try.profile.try.website.try.thumbnail
>
> user.trying{ |u| u.profile.website.thumbnail }
>
> user.trying.profile.website.thumbnail.resolve
>
> It occurs to me the first could be fairly concise if we think of #s
> as possessive:
>
> user.s.profile.s.website.s.thumbnail
>
> Albeit it looks a bit odd.
>
I'd probably use _? instead of "s" for the andand approach:
https://github.com/raganwald/andand
class NullClass
def method_missing(name, *args, &block); nil; end
end
module NullPattern
def _?; nil? ? NullClass.new : self; end
end
BasicObject.send :include, NullPattern
user._?.profile._?.website._?.thumbnail
But anyway, this is kind of how it currently works using Groovy's
pattern... What I don't understand is how you're thinking about
implementing the CoffeeScript pattern:
user.trying.profile.website.thumbnail.resolve
By the way, I'd write it as:
user._?.profile.website.thumbnail.resolve
You can't inherit NullClass from NilClass. Also, you can't force an
instance to behave like a falsey value in Ruby. Avdi made a great job
explaining the reasons:
http://devblog.avdi.org/2011/05/30/null-objects-and-falsiness/
So, how the "trying" approach would be implemented?
Cheers,
Rodrigo.
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Em 08-04-2013 11:50, Trans escreveu:
<blockquote
cite="mid:CAEu+kw20i-xOfxP_E0U1ANcFWujFER-yC1UOMwEgyjySrb47zA@mail.gmail.com"
type="cite">
<div dir="ltr">
<div style=""><span
style="font-family:arial,sans-serif;font-size:13px">There
are at least three other ways to approach this:</span></div>
<div style=""><span
style="font-family:arial,sans-serif;font-size:13px"><br>
</span></div>
<div style=""><span
style="font-family:arial,sans-serif;font-size:13px">�� �� ��
user.try.profile.try.website.try.thumbnail</span><span
style="font-family:arial,sans-serif;font-size:13px"><br>
</span></div>
<div style="">
<br>
</div>
<div><span style="font-family:arial,sans-serif;font-size:13px">��
�� �� user.trying{ |u| u.profile.website.thumbnail }</span><span
style="font-family:arial,sans-serif;font-size:13px"><br>
</span></div>
<div><br>
</div>
<div><span style="font-family:arial,sans-serif;font-size:13px">��
�� �� user.trying.profile.website.thumbnail.resolve</span><span
style="font-family:arial,sans-serif;font-size:13px"><br>
</span></div>
<div><span style="font-family:arial,sans-serif;font-size:13px"><br>
</span></div>
<div style=""><font face="arial, sans-serif">It occurs to me the
first could be fairly concise if we think of #s
as��possessive:</font></div>
<div style=""><span
style="font-family:arial,sans-serif;font-size:13px"><br>
</span></div>
<div>
<div><span style="font-family:arial,sans-serif;font-size:13px">��
�� �� user.s.profile.s.website.s.thumbnail</span><span
style="font-family:arial,sans-serif;font-size:13px"><br>
</span></div>
</div>
<div><span style="font-family:arial,sans-serif;font-size:13px"><br>
</span></div>
<div style=""><span
style="font-family:arial,sans-serif;font-size:13px">Albeit
it looks a bit odd.</span></div>
<div style=""><span
style="font-family:arial,sans-serif;font-size:13px"><br>
</span></div>
</div>
</blockquote>
<br>
I'd probably use _? instead of "s" for the andand approach:<br>
<br>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<a href="https://github.com/raganwald/andand">https://github.com/raganwald/andand</a><br>
<br>
class NullClass<br>
�� def method_missing(name, *args, &block); nil; end<br>
end<br>
<br>
module NullPattern<br>
�� def _?; nil? ? NullClass.new : self; end<br>
end<br>
<br>
BasicObject.send :include, NullPattern<br>
<br>
user._?.profile._?.website._?.thumbnail<br>
<br>
But anyway, this is kind of how it currently works using Groovy's
pattern... What I don't understand is how you're thinking about
implementing the CoffeeScript pattern:<br>
<br>
<span style="font-family:arial,sans-serif;font-size:13px">user.trying.profile.website.thumbnail.resolve</span><span
style="font-family:arial,sans-serif;font-size:13px"><br>
<br>
By the way, I'd write it as:<br>
<br>
</span><span style="font-family:arial,sans-serif;font-size:13px">user._?.profile.website.thumbnail.resolve</span><span
style="font-family:arial,sans-serif;font-size:13px"><br>
</span><br>
You can't inherit NullClass from NilClass. Also, you can't force an
instance to behave like a falsey value in Ruby. Avdi made a great
job explaining the reasons:<br>
<br>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<a
href="http://devblog.avdi.org/2011/05/30/null-objects-and-falsiness/">http://devblog.avdi.org/2011/05/30/null-objects-and-falsiness/</a><br>
<br>
So, how the "trying" approach would be implemented?<br>
<br>
Cheers,<br>
Rodrigo.<br>
<br>
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