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These interview questions were about Ruby, not Rails. If you are hiring for a position where the developer will work primarily with Ruby, it makes sense to ask

These interview questions were about Ruby, not Rails. If you are hiring for a position where the developer will work primarily with Ruby, it makes sense to ask Ruby-specific questions or have a Ruby coding exercise. That shouldn't be the whole interview of course; as you mention, an all-around strong candidate is preferable. That said, the questions in the article don't require much Ruby experience. Anyone with a grasp of OOP concepts could probably get most of them right.

coffeemug 17y ago
I don't completely disagree with you, but a part in me wonders. Ruby isn't a conceptually challenging language - it doesn't introduce any new ideas that you wouldn't have known by coding a combination, of say, Lisp, Perl, and Python. So if you have an all-around strong candidate on your hands that didn't write a line of Ruby in his life, would you pass? I generally prefer candidates that can reason about language design issues - if you can hold your own in a discussion about whether objects or closures are more primitive, can code well in one or two unrelated languages, and can reason about algorithms in the abstract, it's extremely likely you'll have no trouble picking up Ruby within a very short period of time. Of course there are exceptions where you need domain expertise, but I find these situations to be very rare. I'm actually thinking that asking the candidate to design the structure of his own interview might not be a bad idea - you can probably learn a ton about the candidate and avoid the trap of hiring clones of yourself.
tptacek 17y ago
Coffeemug beat me to my comment about this post. We're an all Ruby shop, and I don't think we've ever hired someone who (a) knew Ruby well coming in and (b) wasn't up to speed in under a week. If you're strong with Python, Perl, or Lisp, you will do fine in Ruby. It is not a buyer's market for Ruby devs. Any post that suggests you screen a candidate based on whether they know what the "||=" operator does is offering bad advice.
- oscardelben 17y ago
  Yes but if you are looking to hire people who already know Ruby, they should know at least those basic questions.
  - xtho 17y ago
    The precise semantics of ||= were subject to a longer discussion on ruby-talk. I don't think it's really that important whether it expands to 1.) a || a = b or 2.) a = a || b, is it? So all you would know about a person giving answer 1) is that he/she was subscribed to ruby-talk at that time. I find his answer to his own questions about proc/lambda/blocks unsatisfying since that would be IMHO a good question to identify people who know ruby well.
  - tptacek 17y ago
    The point is that you shouldn't be looking to specifically hire people who know a language you can learn inside of a week.

coffeemug 17y ago

I don't completely disagree with you, but a part in me wonders. Ruby isn't a conceptually challenging language - it doesn't introduce any new ideas that you wouldn't have known by coding a combination, of say, Lisp, Perl, and Python. So if you have an all-around strong candidate on your hands that didn't write a line of Ruby in his life, would you pass? I generally prefer candidates that can reason about language design issues - if you can hold your own in a discussion about whether objects or closures are more primitive, can code well in one or two unrelated languages, and can reason about algorithms in the abstract, it's extremely likely you'll have no trouble picking up Ruby within a very short period of time. Of course there are exceptions where you need domain expertise, but I find these situations to be very rare. I'm actually thinking that asking the candidate to design the structure of his own interview might not be a bad idea - you can probably learn a ton about the candidate and avoid the trap of hiring clones of yourself.

tptacek 17y ago

Coffeemug beat me to my comment about this post. We're an all Ruby shop, and I don't think we've ever hired someone who (a) knew Ruby well coming in and (b) wasn't up to speed in under a week. If you're strong with Python, Perl, or Lisp, you will do fine in Ruby. It is not a buyer's market for Ruby devs. Any post that suggests you screen a candidate based on whether they know what the "||=" operator does is offering bad advice.

oscardelben 17y ago
Yes but if you are looking to hire people who already know Ruby, they should know at least those basic questions.
- xtho 17y ago
  The precise semantics of ||= were subject to a longer discussion on ruby-talk. I don't think it's really that important whether it expands to 1.) a || a = b or 2.) a = a || b, is it? So all you would know about a person giving answer 1) is that he/she was subscribed to ruby-talk at that time. I find his answer to his own questions about proc/lambda/blocks unsatisfying since that would be IMHO a good question to identify people who know ruby well.
- tptacek 17y ago
  The point is that you shouldn't be looking to specifically hire people who know a language you can learn inside of a week.