[ruby-talk:01385] Re: Say hi (bis)

[e-mail] writes:

> one other thing for which it was missing is giving a function instead of a
> block, eg:  
> 
> def f(n); [n,n+1]; end; 
> #l.collect \f 
>   #instead of 
> l.collect{|n| f(n)}

You could use a Proc for this:

  fn = proc {|n| [n, n+1] }

or you can use Object.method to return a Method object for a named
method (optionally converting it to a Proc object:

  fn = self.method(:f).to_proc

> > |-- ?? can't redefine a function
> > 
> > you can.
> 
> i was thinking of:
> 
> # !warning! perl here
> sub f { 1 }
> {  
>   my $f = \&f;
>   *f = sub { print "f called\n"; goto &f };
> }

alias oldF f
def f(*args)
  puts "f called"
  oldF(*args)
end


Renaming using 'alias' is one of the joys of Ruby.

> > |- you have to initialize before doing +=
> > 
> > Explicit initialization is good thing I think.
> > 
> > You can avoid them by
> > 
> >   def <<nil
> >     def +(other)
> >       other
> >     end
> >   end
> 
> i don't quite understand that one :(
> 
> i'd have said:
> 
> class NilClass
>   def +(other); other; end
> end

'nil' is the only instantiation of NilClass, so the two are
effectively the same.



Regards

Dave