In fiddling with ruby, I noticed that the method names can be really interesting – rails (maybe others too, dunno) has some methods that look like:
object.stop?
which is typically used to return a boolean indicating wether or not “stop” is true. Ok, cool. Another interesting method call is
object.close
which appears to be identical to
object.close()
. That part really confused me, and I’m still not sure I have it completely clear.
In python
object.close
and
object.close()
are two very different things. The first is a reference to the instance method close – which you can pass around. The second is a specific invocation to the instance method. In ruby the parentheses appear to be optional if there are no arguments getting passed in to the function.
Update:
Dave Slorah pointed out that the parantheses option thing extends beyond just the no-argument methods – it applies all over the place!
irb(main):010:0> def foo(bar,baz) irb(main):011:1> puts bar irb(main):012:1> puts baz irb(main):013:1> end => nil irb(main):014:0> foo "hello", "world" hello world
My first thought it “Wow – that’s almost Objective-C like…”
Rhonabwy 
You are correct — Ruby offers the lack of parentheses as shorthand for invocation of a parameter-less method.
While convenient, it makes for treating methods as first class objects in Ruby considerably less convenient and, thus, you don’t see methods-as-objects used often in Ruby.
Sad, because it enables some pretty simple, straightforward, and very powerful design patterns.
Instead, Ruby encourages the use of blocks to encapsulate a callable. Powerful in and of itself and enables a different set of patterns not possible with Python’s lambda.
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I haven’t yet grokked the blocks thing in ruby either – but it sort of appeals to me with what it enables. I haven’t yet gotten used to being able to read that code right through and have a gut sense of what it’s supposed to be doing/mean as yet.
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