From: Robert Klemme <shortcutter@...>
Date: 2013-04-16T00:41:47+09:00
Subject: Re: Wondering why no "increment" or "decrement" operator in ruby

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On Mon, Apr 15, 2013 at 4:01 PM, Rob Biedenharn
<rob@agileconsultingllc.com>wrote:


> Why wouldn't the syntactic sugar for ++a be a=a.succ (for "successor")
> since that is defined on more types?
>

Yes, that's even better.  But, as you discovered


> for --a you could use a=a.pred (for "predecessor"), but that's only
> defined on Integer (and had no built-in use like #succ does).
>

#succ and #pred are not that symmetric in terms of availability.  Maybe
Matz also wanted to avoid hiding an assignment inside an operator which
does not contain an equals sign.

And then there are of course the postfix variants of these operators which
need a temp variable or #tap:

a++ -> a.tap { a = a.succ }

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

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<div dir=3D"ltr"><br><div class=3D"gmail_extra"><br><br><div class=3D"gmail=
_quote">On Mon, Apr 15, 2013 at 4:01 PM, Rob Biedenharn <span dir=3D"ltr">&=
lt;<a href=3D"mailto:rob@agileconsultingllc.com" target=3D"_blank">rob@agil=
econsultingllc.com</a>&gt;</span> wrote:<br>
<div>=A0</div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;=
border-left:1px #ccc solid;padding-left:1ex"><div style=3D"word-wrap:break-=
word"><div>Why wouldn&#39;t the syntactic sugar for ++a be a=3Da.succ (for =
&quot;successor&quot;) since that is defined on more types?</div>
</div></blockquote><div><br></div><div style>Yes, that&#39;s even better. =
=A0But, as you discovered</div><div>=A0</div><blockquote class=3D"gmail_quo=
te" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"=
><div style=3D"word-wrap:break-word">
<div>for --a you could use a=3Da.pred (for &quot;predecessor&quot;), but th=
at&#39;s only defined on Integer (and had no built-in use like #succ does).=
</div></div></blockquote></div><br>#succ and #pred are not that symmetric i=
n terms of availability. =A0Maybe Matz also wanted to avoid hiding an assig=
nment inside an operator which does not contain an equals sign.</div>
<div class=3D"gmail_extra"><br></div><div class=3D"gmail_extra">And then th=
ere are of course the postfix variants of these operators which need a temp=
 variable or #tap:</div><div class=3D"gmail_extra"><br></div><div class=3D"=
gmail_extra" style>
a++ -&gt; a.tap { a =3D a.succ }</div><div class=3D"gmail_extra"><br></div>=
<div class=3D"gmail_extra">Kind regards</div><div class=3D"gmail_extra"><br=
></div><div class=3D"gmail_extra">robert<br clear=3D"all"><div><br></div>--=
 <br>remember.guy do |as, often| as.you_can - without end<br>
<a href=3D"http://blog.rubybestpractices.com/">http://blog.rubybestpractice=
s.com/</a>
</div></div>

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