Ruby Tips Part 1 | Hacker News Reader

Ruby Tips Part 1

globaldev.co.uk

48 pointsPeroni14 comments

Sorry, offtopic mini-rant coming: this site (and so many others) become much more readable if you disable the body text CSS. Actually this specific site does quite well when you disable all CSS.

What is with the trend of mid-range gray on white or light gray these days? Does anyone find that easy to read?

Maybe it's old age but I find that annoying too. Looks pretty but is unreadable.

Is this:

    def fibonacci(max=Float::INFINITY)
    # ...
      while i < max
        # ...
      end
    end

better than this:

    def fibonacci(max=nil)
    # ...
      while max && i < max
        # ...
      end
    end

? (genuine question)

yes. The first one does what it's intended to, the second plain fails :)

    Voice-of-Evening:~ $ irb
    irb(main):001:0> max=Float::INFINITY
    => Infinity
    irb(main):002:0> i = 0
    => 0
    irb(main):003:0> i < max
    => true
    irb(main):004:0> max = nil
    => nil
    irb(main):005:0> max && i < max
    => nil

The second version will only provide any result when a specific max value was given, while the first one will loop into infinity.

Yes, I messed up. I meant `!max && i < max`.

Then the code is functionally equivalent, but the first version is much more readable. As pointed out on the parent comment, the first version does one test less, a minor performance benefit.

What you meant is `while !max || max < i`, but the answer is the same: the former will perform better because it only makes one comparison for each iteration of the loop. The latter needs to additionally check the existence of max.

Ruby is neat! Except for this part:

    return nil unless other.is_a?(self.class)

Wait, why? Try to read it aloud and it will make sense. I've seen lot's of hard and confusing syntax but this is not one of them. And I'm not a Ruby developer.

Post conditions are odd if you're not used to them, but once you start to mentally allow for them, they're really quite nice.

Ah, seems everybody misunderstood my comment (not hard to see why). It's not the post conditions that bother me, its the dynamic typing! In my opinion, ruby's duck typing really only works until you actually need it.

Is it a statement-modifier 'unless' that bothers you? `return ... unless ...` is kind of idiomatic way of returning early in the function. You get used to this shortcut ridiculously fast.

I'm a fan of:

  while true do
    puts 'lol'
  end unless true

but seriously, I like postconditions. they're also handy for encoding intent, if you have a pattern of the left-hand-side being the primary logic flow.

this can also be written as

    other.is_a?(self.class) || return

if you prefer that.

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