ruby-core

Issue #13560 has been updated by shevegen (Robert A. Heiler).


What would perhaps be nice would be to have a way to initialize these to nil, upon
attr_* definition, but I guess that would require another name - it would probably
be bad in general to change the attr_* default behaviour at this point.

> In current state, where attr_* methods return nil, it makes class definition more
> prone to errors, especially at code refactoring

I do not know whether it makes anything more prone to errors.

The interesting thing is that I myself only rarely  use the attr_* methods these
days. One reason is that I also want reader methods that have a trailing '?'
(I love them!), but I do not want to carry my custom modifications into my 
gem-projects (I use them locally, but I don't want to require of people to 
go "off default ruby" - it is much better to stay with the idioms of main 
ruby in my opinion). But another reason also is that I have more control 
over methods (readers, setters, getters, accessors) with a custom definition.

It means that I have to write more code though, so sometimes I'd wish that
there would be more ways to automatically define such accessor methods. The
current attr_* ways are fine but I believe that active* (activerecord?) 
uses some custom modifications too, so I may assume that there could be
a need for some more of these. I digress though, feel free to disregard
my comment. :D

----------------------------------------
Feature #13560: Module#attr_ methods return reasonable values
https://bugs.ruby-lang.org/issues/13560#change-64809

* Author: dunrix (Damon Unrix)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
Hi,

I'm suggesting all `Module#attr_` [methods](http://ruby-doc.org/core-2.4.1/Module.html#method-i-attr_accessor) should return array of generated method names, instead of useless `nil`.
Make them more concise across `Module` API, corresponding to logic of [`Module#define_method`](http://ruby-doc.org/core-2.4.1/Module.html#method-i-define_method), allow pass as arguments to visibility `public/protected/private` methods etc.

Concerned method names:

* attr_accessor
* attr_reader
* attr_writer

Demonstration example:

```
class LookBeforeYouLeap
  api_meths = attr_accessor :ruby_api
  # api_meths == [:ruby_api, :ruby_api=]
  private *api_meths

  # Or you can pass generated methods directly
  # protected *attr_reader(:ruby_papi, :ruby_cext)
end

# Assignment to temporary local variable `api_meths` does not pollute class'es
# namespace.
```

I'm aware *attr_** methods also create corresponding instance variables, but `Module` API has no use for them, unlike created accessor methods.

In current state, where *attr_** methods return `nil`, it makes class definition more prone to errors, especially at code refactoring:

```
class ExistingWay
  attr_accessor :ruby_api  # result is nil

  # Need write method names manually
  private :ruby_api, :rby_api=  # throws NameError exception when executed

  # Any change of generated accessor methods names require manual rewrite
  # at each visibility method call also.
end
```




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