From: Robert Klemme <shortcutter@...>
Date: 2009-09-01T22:38:10+09:00
Subject: Re: Private methods’ viability (was: What is the ruby conventions to name private method?)

2009/8/31 Shot (Piotr Szotkowski) <shot@hot.pl>:
> Ryan Davis:
>
>> 4) Don't have private methods if you don't need them.
>> 5) You don't need them. No, really.
>
> I’ll bite. Note: I consider myself a beginner Rubyist and I’d love to
> hear your (and others’!) reasons for the above and/or against the below. :)
>
> I use private methods when I factor them out of my public methods (once
> the public methods have decent spec coverage). This makes me think
> harder on the (hopefully – minimal) public API of my objects and
> prevents me from calling such methods ‘in just that single place
> where it would be useful’; a method’s either useful to the outside
> world (and should be promoted to public API with individual, descriptive
> spec coverage) or not, period. Using private methods helps me keep
> checks on this.

+1

> I also use protected attr_readers so that my objects can tell whether
> they == others of the same kind without exposing their instance
> variables to the outside world; an attr_reader on an Array/Hash/Set
> does not guarantee that the given Array/Hash/Set is not modifiable from
> the outside world¹, hence I’d rather not expose such instance variables
> more than necessary.

-0 - you cannot really prevent access to internals and if you include
attributes in the equivalence relation you usually want to access them
from the outside.

My 0.02 EUR...

> ¹ It’s one of the few places where Ruby diverges from the principle
> of least surprise; I can see certain lovely symmetry and simplicity
> in attr_reader working the same for all variables, but I found the name
> a bit misleading when I started to learn Ruby – my thoughts were that
> it should either not be called a reader or should return a dup of the
> variable in question… (I did get used to this since then, though, and
> realised that other languages’ generic getters usually do the same.)

This is not necessary as a general functionality because there are
immutable classes, others can be frozen and last but not least
sometimes you want to give someone access to internals.

Kind regards

robert


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