Prev: [ANN] Harvested 0.3.0
Next: Google Wave: A new type of "Ruby Quiz" ?
From: Albert Schlef on 11 Apr 2010 21:00
Let's say I have this code:

class Mambo
attr_accesstor :safe
end

Now,

'safe', in my case, is a boolean. Problem is, the getter will be named
'safe', whereas I want it to be 'safe?'.

In other words, how do I make the getter 'safe?' and the setter 'safe'
?
--
Posted via http://www.ruby-forum.com/.

From: Daniel N on 11 Apr 2010 21:03
[Note: parts of this message were removed to make it a legal post.]

There's no built in way in ruby for it to know that you're going to put a
boolean in there. You'll need to do something like

class Mambo
attr_writer :safe

def safe?
!!@safe
end
end

HTH
Daniel

On 12 April 2010 11:00, Albert Schlef <albertschlef(a)gmail.com> wrote:

> Let's say I have this code:
>
> class Mambo
> attr_accesstor :safe
> end
>
> Now,
>
> 'safe', in my case, is a boolean. Problem is, the getter will be named
> 'safe', whereas I want it to be 'safe?'.
>
> In other words, how do I make the getter 'safe?' and the setter 'safe'
> ?
> --
> Posted via http://www.ruby-forum.com/.
>
>

From: Daniel N on 11 Apr 2010 21:13
[Note: parts of this message were removed to make it a legal post.]

On 12 April 2010 11:10, Aaron Patterson <aaron(a)tenderlovemaking.com> wrote:

> On Mon, Apr 12, 2010 at 10:00:06AM +0900, Albert Schlef wrote:
> > Let's say I have this code:
> >
> > class Mambo
> > attr_accesstor :safe
> > end
> >
> > Now,
> >
> > 'safe', in my case, is a boolean. Problem is, the getter will be named
> > 'safe', whereas I want it to be 'safe?'.
> >
> > In other words, how do I make the getter 'safe?' and the setter 'safe'
> > ?
>
> In situations like this, I make two "getters" and leave the assignment
> alone. Other ruby programmers expect your "setters" to be in the form
> of "obj.safe = true", not "obj.safe(true)".
>
> Try something like this:
>
> class Mambo
> attr_accesstor :safe
> alias :safe? :safe
> end
>
> Here it is in action:
>
> irb(main):001:0> class Mambo
> irb(main):002:1> attr_accessor :safe
> irb(main):003:1> alias :safe? :safe
> irb(main):004:1> end
> => nil
> irb(main):005:0> m = Mambo.new
> => #<Mambo:0x000001010cab50>
> irb(main):006:0> m.safe = true
> => true
> irb(main):007:0> m.safe?
> => true
> irb(main):008:0>
>
> --
> Aaron Patterson
> http://tenderlovemaking.com/


Unfortunately this doesn't support safe? being boolean always. It could be
something other than true false (may not be a problem)

If you want to use attr_accessor rather than simply aliasing the method I'd
suggest

def safe?
!!safe
end

This way the expectation of a ? method to return a boolean is preserved.

Cheers
Daniel

From: Albert Schlef on 12 Apr 2010 01:28
Aaron Patterson wrote:
> alias :safe? :safe

Daniel wrote:
> def safe?
> !!@safe
> end


Thank you both. I wanted to make sure there's no built-in way to do
this.

(BTW, in Lisp (CLOS) it's possible to specify the getter/setter names.)
--
Posted via http://www.ruby-forum.com/.

From: Albert Schlef on 12 Apr 2010 01:35
Albert Schlef wrote:
> Thank you both. I wanted to make sure there's no built-in way to do
> this.

Hey, I've just discovered that 'ri' tells me that Module has an
'attr_reader?' method that creates a question-mark attribute.

Problem is, 'ri' displays methods from everything I've installed on my
system, so I can't know if 'attr_reader?' is provided by Ruby itself or
by some wacky gem.
--
Posted via http://www.ruby-forum.com/.

 |  Next  |  Last
Pages: 1 2 3
Prev: [ANN] Harvested 0.3.0
Next: Google Wave: A new type of "Ruby Quiz" ?