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0 pointsrlivsey15y ago0 comments

Yep, the equivalent would probably be something along the lines of:

    if baz > 10
      func = :foo
    else
      func = :bar
    end

    result = self.send(func)

0 comments

8 comments · 1 top-level

sandal15y ago· 7 in thread

That may accomplish the same thing, but the direct translation would be:

    if baz > 10
       func = method(:foo)
    else
       func = method(:bar)
    end
 
    result = func.call

Here, we actually deal with the Method objects, rather than just sending a dynamic message. Although the send() approach would be closer to idiomatic Ruby, I wanted to emphasize that dealing with methods as first class objects in Ruby is indeed possible.

mcantor15y ago

I HATE dealing with first class functions in Ruby. I understand that it was a design choice, but man, in Python you can pass a function or a lambda and you just don't have to worry about which one you're calling. In Ruby, () will explode on a Proc object. What is with that?!!?

Twisol15y ago

Because () doesn't call a method, it's simply used where a method call occurs. To call a callable object, you use #call or (as mentioned by epochwolf) #[], the latter of which I personally detest.

It's fun to contrast this with Lua, by the way.

2 more replies

carbon815y ago

Are you actually passing around methods in Ruby and, if so, why? As I've pointing out in the past (http://news.ycombinator.com/item?id=1141245), passing around methods is very rare in Ruby due to the flexibility of Procs.

1 more reply

sandal15y ago

Well, a Method object and a Proc are two different things, but somewhat similar, so it still makes sense to discuss Proc behavior here. I would like it if this worked:

    a = lambda { |x| x + 1 }
    a(3) #=> 4

But since it doesn't, the alternatives are not too bad (though likely far too numerous for Python tastes)

    a[3] #=> 4
    a.(3) #=> 4 (on Ruby 1.9)

I think that Ruby's ability to call methods without () make for better readability in the case of writing domain specific interfaces, but come at a cost in other places. Personally I think it's a worthwhile tradeoff but I can see the other side of the argument.

epochwolf15y ago

You can call a proc with []

    p = Proc.new {|str| puts "Hello #{str}" }
    p["World"] # prints "Hello World"

1 more reply

ataggart15y ago

This discussion really makes me appreciate clojure.

rue15y ago

Why is that?

j / k navigate · click thread line to collapse

0 comments

8 comments · 1 top-level

sandal15y ago· 7 in thread

That may accomplish the same thing, but the direct translation would be:

    if baz > 10
       func = method(:foo)
    else
       func = method(:bar)
    end
 
    result = func.call

mcantor15y ago

Twisol15y ago

Because () doesn't call a method, it's simply used where a method call occurs. To call a callable object, you use #call or (as mentioned by epochwolf) #[], the latter of which I personally detest.

It's fun to contrast this with Lua, by the way.

2 more replies

carbon815y ago

1 more reply

sandal15y ago

Well, a Method object and a Proc are two different things, but somewhat similar, so it still makes sense to discuss Proc behavior here. I would like it if this worked:

    a = lambda { |x| x + 1 }
    a(3) #=> 4

But since it doesn't, the alternatives are not too bad (though likely far too numerous for Python tastes)

    a[3] #=> 4
    a.(3) #=> 4 (on Ruby 1.9)

epochwolf15y ago

You can call a proc with []

    p = Proc.new {|str| puts "Hello #{str}" }
    p["World"] # prints "Hello World"

1 more reply

ataggart15y ago

This discussion really makes me appreciate clojure.

rue15y ago

Why is that?

j / k navigate · click thread line to collapse