Comments on Ethan's Software Blog: The options Hash, a classic ruby pattern

@Robert I think I like your version best out of w...

2010-11-07T13:03:09.758-06:00

@Robert

I think I like your version best out of what's on the page so far. Defaults are declared in one place, but in context of the method. Those Rails guys know what they're doing. :)

Rails usually does it this way: def method(option...

2010-11-07T10:56:45.499-06:00

Rails usually does it this way:

def method(options={})
options.reverse_merge!(:volume => 10)
ring(options)
end

@first_Anonymous I like that approach, although I...

2010-11-04T13:05:55.289-05:00

@first_Anonymous

I like that approach, although I haven't used it myself. The only thing that might make me think for a minute about not using it is that I habitually avoid instance variables if possible, but in this case since the only thing that references it is the defaults method, it's really not a "risky" imposition on an otherwise functional process. I may refactor some of my current code to do it this way to see how I like it, thanks for the comment!

@second_Anonymous

What I mean is that instead of calling "ring!" in each branch of the conditional, you could do something like this:

opts = {:volume=>3}
if caller.is_my_friend?
opts.merge!(:volume=>6,:ringtone=>:smooth_jazz)
elsif caller.is_my_boss?
opts.merge(:volume=>11,:ringtone=>:totally_obnoxious)
end

phone.ring!(opts)

I don't know how much better that is, really, since it requires introducing another local variable, but if you prefer only calling ring in one place rather than inside each conditional branch and the each clause at the end, it's viable.

In the first paragraph you say: "the conditio...

2010-11-04T11:41:37.989-05:00

In the first paragraph you say: "the conditional could be constructed to just build the hash and only call the method in one place". Can you please show an example?

I prefer a pattern like this, so default values ar...

2010-11-04T11:15:17.490-05:00

I prefer a pattern like this, so default values are reusable and not mixed throughout the code.

class MyToolkit
def defaults
@options ||= {
:opt => "value",
:integer => 33,
:type => "awesome"
}
end

def method(opts={})
# one time only option overrides
opts = defaults.merge(opts)
# OR... you can make the settings persist between method calls
defaults.merge!(opts)

# ... now do something useful
end
end