[#400858] Support for multiple Inheritance by classes — Ross Konsolebox <lists@...>

Will Ruby ever support multiple inheritance through classes instead of

23 messages 2012/11/03
[#400859] Re: Support for multiple Inheritance by classes — Arlen Cuss <ar@...> 2012/11/03

I think I can say "no" with a fair amount of confidence.

[#400902] Re: Support for multiple Inheritance by classes — Ross Konsolebox <lists@...> 2012/11/04

Arlen Cuss wrote in post #1082618:

[#400904] Re: Support for multiple Inheritance by classes — Peter Hickman <peterhickman386@...> 2012/11/04

Even though other languages handle multiple inheritance without any

[#400865] why does UnboundMethod need to remember the class it was retrieved from (not merely owner)? — "Mean L." <lists@...>

class Base; def foo; end end

17 messages 2012/11/03

[#400914] login web page using mechanize — john smith <lists@...>

new to ruby, love the language. read programmatic programmers guide to

25 messages 2012/11/04

[#400985] How to merge two or more hashes in to one? — "Jermaine O." <lists@...>

Hi everyone.

14 messages 2012/11/06

[#401026] Site down watir-webdriver — ajay paswan <lists@...>

Whenever a site is down it keeps on looking for it for sometime and

14 messages 2012/11/07

[#401027] Closing popups watir-webdriver — ajay paswan <lists@...>

Sometimes popup comes when a link is clicked, sometimes popup comes when

14 messages 2012/11/07

[#401125] Complete newbie — "Carlos A." <lists@...>

Hey guys!

14 messages 2012/11/10

[#401161] Convert date to string — Ferdous ara <lists@...>

Hi

12 messages 2012/11/11

[#401173] question on watir — Raj pal <lists@...>

I am automating Idit application using Ruby, at one screen I can't feed

233 messages 2012/11/12

[#401191] Extending Array instances — Charles Hixson <charleshixsn@...>

I'm trying to figure out a good way to extend an Array, when the items

17 messages 2012/11/12
[#401195] Re: Extending Array instances — Brian Candler <lists@...> 2012/11/12

Charles Hixson wrote in post #1084111:

[#401200] Efficient way for comparing records between 2 large files (16 million records) — Ruby Student <ruby.student@...>

Team,

9 messages 2012/11/12

[#401274] following along with "Beginning Ruby." — Al Baker <lists@...>

I'm having trouble following along with some of the examples in this

15 messages 2012/11/15

[#401279] Question on exceptions — Justin Gamble <lists@...>

Hello! I have a simple bank program where I have to have an exception

16 messages 2012/11/15
[#401281] Re: Question on exceptions — Justin Gamble <lists@...> 2012/11/15

What is the reason of doing the .new(...)in

[#401295] Re: Question on exceptions — Brian Candler <lists@...> 2012/11/16

Justin Gamble wrote in post #1084635:

[#401296] Re: Question on exceptions — tamouse mailing lists <tamouse.lists@...> 2012/11/16

On Fri, Nov 16, 2012 at 1:43 AM, Brian Candler <lists@ruby-forum.com> wrote:

[#401301] Alternatives to methods for large number of nested "ifs" — Philip Rhoades <phil@...>

People,

11 messages 2012/11/16

[#401336] Advice for simple client/server application — Panagiotis Atmatzidis <atma@...>

Hello,

12 messages 2012/11/17

[#401364] Metaprogramming — "Aurimas N." <lists@...>

Hello,

12 messages 2012/11/19

[#401404] "undefined method `synchronize' for #<Mutex:0xa0f5adc>" from embedded Ruby program — Graham Menhennitt <graham@...>

I'm writing a C++ program (on Centos 5 Linux) that embeds a Ruby 1.9.3

9 messages 2012/11/21

[#401422] how to increase variable inside the while loop — Ferdous ara <lists@...>

Hi, my question might be confusing as its hard for me to make it clear,

12 messages 2012/11/21

[#401451] Arrays with records as objects — Steve Tucknott <lists@...>

I am completely new to Ruby.

11 messages 2012/11/22

[#401458] working with mysql in ruby — john smith <lists@...>

i have been trying to successfully connect ruby with mysql. there are a

17 messages 2012/11/22

[#401567] click on link not working with ie #watir-webdriver — ajay paswan <lists@...>

Greetings,

12 messages 2012/11/26

[#401578] atomic statements in multithreading — ajay paswan <lists@...>

suppose I am working in multiple thread each thread runs following

10 messages 2012/11/26

[#401607] Novice: Understanding instance 'variables' and methods — Steve Tucknott <lists@...>

A question - or comment - on instance variables.

10 messages 2012/11/26

[#401644] Getting the smallest Items of an Array — "Ismail M." <lists@...>

Hello guys,

14 messages 2012/11/27

[#401655] gem problems(sigh) — Al Baker <lists@...>

i tried to make a gem and tried to build the spec file and this is what

10 messages 2012/11/28

[#401688] sorting data from a file — "Ismail M." <lists@...>

Hey guys,

16 messages 2012/11/28

[#401706] Newbie question: (free) on-line courses? — Ken D'Ambrosio <ken@...>

Hello, all. There's a bunch of free on-line training for Javascript,

11 messages 2012/11/28

Re: Support for multiple Inheritance by classes

From: Robert Klemme <shortcutter@...>
Date: 2012-11-06 21:04:20 UTC
List: ruby-talk #400993
On Mon, Nov 5, 2012 at 6:44 PM, Marc Heiler <lists@ruby-forum.com> wrote:

> There is one thing that is however not looked at much at
> all in this discussion - less the distinction between
> multiple inheritance vs. module mixins, and much more so
> what the distinction class vs. module actually serves.
>
> Because I often feel that the distinction between classes
> and modules is much more arbitrary than seems to be reasonable.
>

The difference between class and module in Ruby is
- classes can be instantiated, modules can't
- classes can be inherited (SI), modules can be included (MI)

Did I miss any?  Other than that both are identical (e.g. both can be used
as namespace).  For me the more dramatic difference is actually the first
one because despite the differences between SI and MI in Ruby it's just
gradual (i.e. the number of items to inherit from - 1 for classes, n for
modules).

So if we assume for a moment that we agree on the most significant
difference then it follows quite naturally (for me at least) that classes
should be used for entities, tangible things while modules should rather be
used for capabilities (behavior).  And I believe you can see that
distinction at work in the standard library: there's Array which is a list
of objects (entity) and Enumerable which is a set of capabilities.


> But why is that behaviour contained within a module? Why
> could we not assume that ALL behaviour of every object
> resides in an (perhaps invisible) module?
>
> Then we could use classes the same way as modules.
>

I do not understand how this follows from the premise.  If all behavior
would reside in modules than classes would not contain behavior at all.
But then classes and modules could not be used the same way.  What am I
missing here?


> Why must there be this distinction between classes and
> modules in this way?
>

I do not think there is a reason why the distinction "must" be there.  It's
just what Matz designed the language to be.  I think the distinction I was
trying to make above is actually not too unreasonable.  It seems so far it
has served the language quite well so far.

Kind regards

robert

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

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