Ruby doesn't implement x++ for Fixnum's because ???
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From: Tobias Cohen on 5 Nov 2009 06:21 On 05/11/2009, at 1:31 AM, Marnen Laibow-Koser wrote: > I believe you are quite wrong. If a destructive function like gsub! > can > be implemented as a method, then I see no reason that +=, |=, or > postfix > ++ couldn't be. It can be done, if you are willing to make your numbers mutable: class MutableNum def initialize n @n = n end def pp @n += 1 @n - 1 end def method_missing symbol, *args @n.method(symbol).call(*args) end def to_s @n.to_s end end a = MutableNum.new 1 puts a.pp #=> 1 puts a #=> 2 Having said that, I agree with others that the post-increment operator is not needed in Ruby at all. -- Tobias Cohen http://tobiascohen.com/
From: David A. Black on 5 Nov 2009 07:54 Hi -- On Thu, 5 Nov 2009, Tony Arcieri wrote: > On Wed, Nov 4, 2009 at 2:41 PM, Marnen Laibow-Koser <marnen(a)marnen.org>wrote: > >> What semantics do you intend here? I'm not sure I understand. >> > > You can think of it like: > > alias_method :++, :increment! But what would it mean to send the message increment! to, say, the object 10? In the same vein: >> 10.succ! NoMethodError: undefined method `succ!' for 10:Fixnum David -- The Ruby training with D. Black, G. Brown, J.McAnally Compleat Jan 22-23, 2010, Tampa, FL Rubyist http://www.thecompleatrubyist.com David A. Black/Ruby Power and Light, LLC (http://www.rubypal.com)
From: Aldric Giacomoni on 5 Nov 2009 08:06 David A. Black wrote: > > But what would it mean to send the message increment! to, say, the > object 10? In the same vein: > > >> 10.succ! > NoMethodError: undefined method `succ!' for 10:Fixnum I agree with David.. At which point are we completely violating the principle of least surprise? A number is a number is a number. It took me all of half an hour to forget about ++ and I haven't looked back since. I -like- typing +=1 because it, simply put, makes sense. -- Posted via http://www.ruby-forum.com/.
From: Tony Arcieri on 5 Nov 2009 12:12 [Note: parts of this message were removed to make it a legal post.] On Thu, Nov 5, 2009 at 3:40 AM, Gavin Sinclair <gsinclair(a)gmail.com> wrote: > > def ++ > > incrementing_logic_goes_here > > end > > > > I could see this as being handy > > What's wrong with > > def inc > incrementing_logic_goes_here > end > > How is that any different? > What's wrong with Array#push? Why do we need Array#<<? How is that any different? -- Tony Arcieri Medioh/Nagravision
From: David A. Black on 5 Nov 2009 19:28
Hi-- On Fri, 6 Nov 2009, Tony Arcieri wrote: > On Thu, Nov 5, 2009 at 3:40 AM, Gavin Sinclair <gsinclair(a)gmail.com> wrote: > >>> def ++ >>> incrementing_logic_goes_here >>> end >>> >>> I could see this as being handy >> >> What's wrong with >> >> def inc >> incrementing_logic_goes_here >> end >> >> How is that any different? >> > > What's wrong with Array#push? Why do we need Array#<<? How is that any > different? irb(main):001:0> [].push(1,2,3) => [1, 2, 3] irb(main):002:0> [].<<(1,2,3) ArgumentError: wrong number of arguments (3 for 1) :-) But I know that's not what you meant. The thing is, a method called ++ that did in-place incremention would not be meaningful for numbers (if I understand correctly that you mean it would be similar to succ!), and having it for other objects would probably just lead to more confusion. That's my hunch, at least. David -- The Ruby training with D. Black, G. Brown, J.McAnally Compleat Jan 22-23, 2010, Tampa, FL Rubyist http://www.thecompleatrubyist.com David A. Black/Ruby Power and Light, LLC (http://www.rubypal.com) |