From: Brian Candler <b.candler@...>
Date: 2009-08-25T21:51:31+09:00
Subject: Re: operators vs. methods

7stud -- wrote:
>>> So, where might I find a list of the special sugary methods?
>> 
>> There is a list in the printed edition of the Pickaxe IIRC.
>> 
> 
> Ah, yes.  p. 339 (pickaxe2).  The ones with check marks preceding them 
> in the operator table.
> 
> In order of precedence(highest at the top):
> 
> []  []=
> **
> !   ~   +   -  (unary plus and minus, e.g. -1)
> *  /  %
> +  -
>>>  <<
> &
> ^   |
> <=   <   >  >=
> <=>  ==  ===  !=  =~  !~

Note that the majority of these call a method whose symbolic name is the 
same as the operator itself, but there are some exceptions:

(1) unary plus and unary minus are :+@ and :-@

>> 3.send(:-@)
=> -3

(2) !~ and != operators do not map directly to method calls, but call 
:=~ and :== and negate the answers

>> class Foo; def ==(bar); puts "== #{bar}"; end; end
=> nil
>> Foo.new == "x"
== x
=> nil
>> Foo.new != "x"
== x
=> true

I have written programs which use x.send(:[]=, val). I call this smiley 
programming :-@
-- 
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