With block in ruby

ruby-talk
1

is there any way in ruby to do something like:

with thisobject do
....

end

···

--
Posted via http://www.ruby-forum.com/.

2

Depends on what you want to do, probably use #instance_eval e.g

irb(main):001:0> "foo".instance_eval do p size end
3
=> 3

Or you can use #tap (1.9)

irb(main):002:0> "foo".tap do |x| p x.size end
3
=> "foo"

Cheers

robert

···

On Mon, Mar 28, 2011 at 5:05 PM, Mario Ruiz <tcblues@gmail.com> wrote:

is there any way in ruby to do something like:

with thisobject do
....

end

--
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

3

Do you mean something like this?

def with(arg)
  yield arg
end

with [1,2,3] do |i|
  p i.size # => 3
end

···

On Tue, Mar 29, 2011 at 12:05 AM, Mario Ruiz <tcblues@gmail.com> wrote:

is there any way in ruby to do something like:

with thisobject do
....

end

--
Posted via http://www.ruby-forum.com/\.

--
Haruka YAGNI
hyagni@gmail.com

4

You could use

obj.instance_eval do
  puts self.inspect
end

or:

obj.instance_eval do |something|
  puts something.inspect
end

···

On Mon, Mar 28, 2011 at 4:05 PM, Mario Ruiz <tcblues@gmail.com> wrote:

is there any way in ruby to do something like:

with thisobject do
....

end

5

Yes, you can accomplish that with instance_eval:

    def with(obj, &block)
      obj.instance_eval &block
    end

    with do
      p length # => 0
    end

-- fxn

···

On Mon, Mar 28, 2011 at 5:05 PM, Mario Ruiz <tcblues@gmail.com> wrote:

is there any way in ruby to do something like:

with thisobject do
....

end

6

try #instance_eval

eg,

def with o, &block
  o.instance_eval &block
end
#=> nil

with "test" do
  puts capitalize
end
Test

best regards -botp

7

Also available in 1.8.7 :).

···

On Mon, Mar 28, 2011 at 5:13 PM, Robert Klemme <shortcutter@googlemail.com> wrote:

Or you can use #tap (1.9)