Comments on: factory method in ruby

By: Kevin Rutherford

Kevin Rutherford — Fri, 24 Jul 2009 08:58:31 +0000

@Daniel, I agree with your concern about name clashes. In the final code I did indeed name the methods ‘to_reek_source’.

By: Daniel Lucraft

Daniel Lucraft — Fri, 24 Jul 2009 08:50:40 +0000

That’s great, but aren’t you worried about naming conflicts with other gems? You could call the methods ‘to_reek_source’ instead for instance. Or if you’re not worried about this, why not?

By: Ashley Moran

Ashley Moran — Sun, 19 Jul 2009 10:09:37 +0000

The thing that makes me go hmmm is (still) the way reek accepts both source and pathnames. If this was not the case, you could define #to_source_string on String, File, IO, etc, and have a method like Source.from_source_source – possibly without the homonym abuse. That would factor out the `Reek::Source.new`, but leave the conversion code where it belongs.

(BTW I’m starting to prefer instance-method factory methods, having used a few lately.)

By: TimM

TimM — Fri, 17 Jul 2009 16:40:31 +0000

This is actually a common pattern in Smalltalk (which I recall the Gof book also used?) and I think they use the term Converter as well, so your in a good place!

By: Chaz

Chaz — Thu, 16 Jul 2009 03:30:08 +0000

It’s a good enough name, and now I at least have something to call these. I use C# extension methods to do exactly this sort of thing.

By: Kevin Rutherford

Kevin Rutherford — Tue, 14 Jul 2009 18:50:08 +0000

Nice, thanks for the link. In my example above, the name-collision problem is another force pushing back towards the Java-style Factory Method approach. I suppose naming the extension methods “to_reek_source” would pretty much avoid that possibility too.

By: Dan Kubb

Dan Kubb — Tue, 14 Jul 2009 16:43:41 +0000

There was an article last month that kicked off a series of other blog posts on solving a related problem to yours:

http://sandimetz.com/2009/06/ruby-case-statements-and-kindof.html

By: Kevin Rutherford

Kevin Rutherford — Tue, 14 Jul 2009 16:29:50 +0000

Doh! I’ve just figured out the major reason to use Converters: The need to know which parts of the object should be dug out and passed to the Source’s constructor. The example above is trivial in this regard, but one could imagine it being a deal-clincher for something big and hairy that contains “source code” in a non-obvious (and non-public) way.

(See, this is why the Pomodoro technique doesn’t work for me — I’m just so sloooow…)