On 6 Feb 2009, at 15:58, Kenneth McDonald wrote:
> > OK, I see how this works now, but I can't figure out how to get extra > args in > there, i.e. something like [1, 2, 3].collect(&:modulo, 2) doesn't work > because > it's improper Ruby syntax. I assume there's a reason extra args are > allowed, > so could someone give a brief illustration of the calling convention? > I don't think you can - you just have to use the longhand syntax in those cases. Fred > Thanks in advance, > Ken > > > On Feb 5, 2009, at 6:13 PM, [email protected] wrote: > >> >> It is not possible in "plain" ruby because Rails extends the Symbol >> class with the possibility of converting it into a Proc (that's what >> happens when you precede something with a &). From the Rails source >> code: >> >> unless :to_proc.respond_to?(:to_proc) >> class Symbol >> # Turns the symbol into a simple proc, which is especially useful >> for enumerations. Examples: >> # >> # # The same as people.collect { |p| p.name } >> # people.collect(&:name) >> # >> # # The same as people.select { |p| p.manager? }.collect { |p| >> p.salary } >> # people.select(&:manager?).collect(&:salary) >> def to_proc >> Proc.new { |*args| args.shift.__send__(self, *args) } >> end >> end >> end >> >> And it does come very handy indeed. >> Balint >> >> On Feb 6, 1:07 am, Kenneth McDonald >> <[email protected]> >> wrote: >>> I've seen a claim on the web that &:f is just Ruby shorthand for >>> &proc >>> { |i| i.f }, but I've certainly never been able to get this &:f >>> notation to work in standard ruby. >>> >>> Thanks, >>> Ken >>> > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
