From: Sam Roberts <sroberts@...>
Date: 2003-03-16T02:24:34+09:00
Subject: Re: Overloaded operator interprets block as hash (bug?)

Quoteing ptkwt@shell1.aracnet.com, on Sat, Mar 15, 2003 at 05:44:40PM +0900:
> In article <b4ughr02k6f@enews4.newsguy.com>,
> Phil Tomson <ptkwt@shell1.aracnet.com> wrote:
> >In article <3E729E3F.7020007@day-reynolds.com>,
> >Lennon Day-Reynolds  <lennon@day-reynolds.com> wrote:
> >True, but...
> >1) I'm sort of creating a domain specific language from Ruby (an HDL) and 
> >I'm trying to hide that sort of thing from the user.
> >2) I'm wondering if this is some sort of bug? 
> 
> I was just talking to some folks on IRQ and Apparently it's not a bug,
> you've got to do:  
> f.<< {puts "An Action"}
> 
> The '.' is needed in this case.

Yeah, but in that case you're just calling << directly as if it was a function,
so why not just MAKE a function:

f.add {puts "an Action"}

Having a method with the same name as an operator << is useful so that ruby
hooks statements like

a << b

and converts the statement to

a.<<(b)

I think having a method called << that can't actually be used as

a << b

is pretty confusing! :-)

I guess its not considered a bug because a block isn't an arg, and the ruby syntax
doesn't allow blocks on binary operators, it appears, I just tried!

[ensemble] ~/p/ruby/vcard $ irb
irb(main):001:0> class T; def <<(arg); yield "hi #{arg}"; end; end
nil
irb(main):002:0> t = T.new
#<T:0x170a1c>
irb(main):005:0> t << 5 { |y| p y }
SyntaxError: compile error
(irb):5: parse error
t << 5 { |y| p y }
        ^
        from (irb):5

Cheers,
Sam