From: Stefan Holst <mail@...>
Date: 2005-10-21T19:22:59+09:00
Subject: Re: Fun with function definitions

Anders H�ckersten wrote:
> Me and a friend realised earlier today that this is actually a legal
> Ruby program:
> foo(def foo(a=nil)
>         puts "hello"
>     end)
> foo
> 
> The fact that this works seems to be a side effect of Ruby's semantics
> rather than an intended feature, but maybe it's actually useful to be
> able to do this? I can't think of any (practical) use of it -
> suggestions are welcome.
> 
> Regards,
> Anders

neat. i experimented a bit an found this one:

irb(main):027:0> foo def foo(o); o+'o'; end || foo('f')
=> "foo"

interestingly, 'or' and || are not the same:

irb(main):030:0> nil or 'fo'
=> "fo"
irb(main):031:0> nil || 'fo'
=> "fo"
irb(main):032:0> foo(nil or 'fo')
SyntaxError: compile error
(irb):32: syntax error
foo(nil or 'fo')
           ^
(irb):32: syntax error
         from (irb):32
         from (null):0
irb(main):033:0> foo(nil || 'fo')
=> "foo"

'or' works however with an extra parenthesis:

irb(main):034:0> foo((nil or 'fo'))
=> "foo"

and even

irb(main):035:0> foo((nil; 'fo'))
=> "foo"

ry
stefan