From: Nokan Emiro <uzleepito@...>
Date: 2013-01-26T07:52:51+09:00
Subject: limitations

--e89a8fb1f27a5ada4004d424c9a2
Content-Type: text/plain; charset=UTF-8

Hi,

Is there any way to somehow redefine operations like '&&' between my
objects?
'&&' is not defined as a method so I can't just overload it.  (Ruby does
not care
if an object responds to :&&, it is simply not used.)  Operators with
higher precedence
than '&&' usually work fine -- except '[]='.  Seems like above '&&' it is
the object's
responsibility to do operations and below that line it is the language
itself that
enforces the rules.  But is there a way to define custom code what should
de done by
an expression like 'x && y'?

The same limitation bothers me with '||', and with 'and', 'or' and 'not'.
(Yes, I know that they are not operators but designed to be flow control
keywords,
however they are often used as operators...)

At the same time I'm struggling with the []=.  The strange thing with this
is
that the return value of the []= method is abandoned by Ruby but I expected
it to be the value of the expression that the []= method returns:

class X
  def []=(key, value)
    "I want to be the value!!"
  end
end
x = X.new
x[123] = 456   #=> 456

The value of the last expression is 456, and not the string.  I'd like to
get back the whole
x object instead of the right hand side value here.  Yes, I know that the
value of assignments
is the rhs value, but assignments in general are out of the scope of an
object, while []=
is an exceptional one.  It is done by the object itself, so it would be
logical to give the
power to the object to decide the value of the operation.  Is this a
deliberate behaviour or
just nobody cares the value of it?

--e89a8fb1f27a5ada4004d424c9a2
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

<div>Hi,</div><div><br></div>Is there any way to somehow redefine operation=
s like &#39;&amp;&amp;&#39; between my objects?<div>&#39;&amp;&amp;&#39; is=
 not defined as a method so I can&#39;t just overload it. =C2=A0(Ruby does =
not care</div>
<div>if an object responds to :&amp;&amp;, it is simply not used.) =C2=A0Op=
erators with higher precedence</div><div>than &#39;&amp;&amp;&#39; usually =
work fine -- except &#39;[]=3D&#39;. =C2=A0Seems like above &#39;&amp;&amp;=
&#39; it is the object&#39;s</div>
<div>responsibility to do operations and below that line it is the language=
 itself that</div><div>enforces the rules. =C2=A0But is there a way to defi=
ne custom code what should de done by</div><div>an expression like &#39;x &=
amp;&amp; y&#39;?</div>
<div><br></div><div>The same limitation bothers me with &#39;||&#39;, and w=
ith &#39;and&#39;, &#39;or&#39; and &#39;not&#39;.</div><div>(Yes, I know t=
hat they are not operators but designed to be flow control keywords,</div>
<div>however=C2=A0they are=C2=A0often used as operators...)</div><div><br><=
/div><div>At the same time I&#39;m struggling with the []=3D. =C2=A0The str=
ange thing with this is</div><div>that the return value of the []=3D method=
 is abandoned by Ruby but I expected</div>
<div>it to be the value of the expression that the []=3D method returns:</d=
iv><div><br></div><div>class X</div><div>=C2=A0 def []=3D(key, value)</div>=
<div>=C2=A0 =C2=A0 &quot;I want to be the value!!&quot;</div><div>=C2=A0 en=
d</div><div>end</div>
<div>x =3D X.new</div><div>x[123] =3D 456 =C2=A0 #=3D&gt; 456</div><div><br=
></div><div>The value of the last expression is 456, and not the string. =
=C2=A0I&#39;d like to get back the whole</div><div>x object instead of the =
right hand side value here. =C2=A0Yes, I know that the value of assignments=
</div>
<div>is the rhs value, but assignments in general are out of the scope of a=
n object, while []=3D</div><div>is an exceptional one. =C2=A0It is done by =
the object itself, so it would be logical to give the</div><div>power to th=
e object to decide the value of the operation. =C2=A0Is this a deliberate b=
ehaviour or</div>
<div>just nobody cares the value of it?</div><div><br></div>

--e89a8fb1f27a5ada4004d424c9a2--