4 ms·

Didn't see anyone mention this little gem about Ruby: a = [1,2,3] x = :foo puts x a = a.map do |x| x+1 end See anything wrong here? (hint: what is the

Didn't see anyone mention this little gem about Ruby: a = [1,2,3] x = :foo puts x a = a.map do |x| x+1 end See anything wrong here? (hint: what is the value of x?)

prog 16y ago
Yes, thats surprising behavior. Fortunately its fixed in 1.9. :) Spoiler alert: . . . 1.8.x produces 3 while 1.9 produces :foo
- jluxenberg 16y ago
  Hmm, interesting. I suspect this will break many things, but I'm happy that they have changed it.
  - kemiller 16y ago
    The problem is not as pervasive as you might think, though it does happen.
- lincolnq 16y ago
  Why was this broken in the first place? (What abomination of semantics would cause this behaviour)?
  - gnaritas 16y ago
    Closure variables not having their own scope and shadowing method level vars. They're simply implemented as method level vars, so not true closures.
    - lincolnq 16y ago
      I got that, but I don't understand why it should gain the value 3 before a single execution of the loop.
      - mike 16y ago
        It's only at the end that the value of x is 3. The puts x immediately after x = :foo does print :foo
bartl 16y ago
All I can see is that this code makes no sense whatsoever to me. I guess that means that Ruby is not for me...
- Zak 16y ago
  Any programming language you don't know is bound to look something like line noise with some words mixed in.
  - JadeNB 16y ago
    > Any programming language you don't know is bound to look something like line noise with some words mixed in. Nuh-uh, not APL! That looks like line noise with no words mixed in. :-)
gcv 16y ago
Here's another fun thing in Ruby: irb(main):001:0> x = true or "hi" => true irb(main):002:0> x => true irb(main):003:0> x = false or "hi" => "hi" irb(main):004:0> x => false What? Short-circuit evaluation doesn't work in an assignment..? Oh. irb(main):005:0> x = (false or "hi") => "hi" irb(main):006:0> x => "hi" In fairness, the || operator does not require explicit parentheses — but I still hold that operator precedence is just evil.
- brettnak 16y ago
  I actually was bitten by this just 2 weeks ago. It took me quite a while to figure this out.
jpr 16y ago
Sometimes I wonder whether I should really try Ruby, but brainfarts like these always remind me why I decided against it the last time.

Didn't see anyone mention this little gem about Ruby: a = [1,2,3] x = :foo puts x a = a.map do |x| x+1 end See anything wrong here? (hint: what is the value of x?)

prog 16y ago

Yes, thats surprising behavior. Fortunately its fixed in 1.9. :) Spoiler alert: . . . 1.8.x produces 3 while 1.9 produces :foo

jluxenberg 16y ago
Hmm, interesting. I suspect this will break many things, but I'm happy that they have changed it.
- kemiller 16y ago
  The problem is not as pervasive as you might think, though it does happen.
lincolnq 16y ago
Why was this broken in the first place? (What abomination of semantics would cause this behaviour)?
- gnaritas 16y ago
  Closure variables not having their own scope and shadowing method level vars. They're simply implemented as method level vars, so not true closures.
  - lincolnq 16y ago
    I got that, but I don't understand why it should gain the value 3 before a single execution of the loop.
    - mike 16y ago
      It's only at the end that the value of x is 3. The puts x immediately after x = :foo does print :foo

bartl 16y ago

All I can see is that this code makes no sense whatsoever to me. I guess that means that Ruby is not for me...

Zak 16y ago
Any programming language you don't know is bound to look something like line noise with some words mixed in.
- JadeNB 16y ago
  > Any programming language you don't know is bound to look something like line noise with some words mixed in. Nuh-uh, not APL! That looks like line noise with no words mixed in. :-)

gcv 16y ago

Here's another fun thing in Ruby: irb(main):001:0> x = true or "hi" => true irb(main):002:0> x => true irb(main):003:0> x = false or "hi" => "hi" irb(main):004:0> x => false What? Short-circuit evaluation doesn't work in an assignment..? Oh. irb(main):005:0> x = (false or "hi") => "hi" irb(main):006:0> x => "hi" In fairness, the || operator does not require explicit parentheses — but I still hold that operator precedence is just evil.

brettnak 16y ago
I actually was bitten by this just 2 weeks ago. It took me quite a while to figure this out.

jpr 16y ago

Sometimes I wonder whether I should really try Ruby, but brainfarts like these always remind me why I decided against it the last time.