Comments on: Understanding Ruby blocks, Procs and methods

By: Bryan

Bryan — Tue, 26 Jan 2010 22:00:22 +0000

Hi there,

Nice article.

What I have a hard time with is knowing when to use a plain method and when to use a Proc-object.

Your thoughts ?

btw:
Isn’t the shortcut for Proc.new not simply proc instead of lambda which is something on it’s own ?

By: jimmi

jimmi — Tue, 26 Jan 2010 10:53:05 +0000

Complex topics, simply presented…..
helps a lot, thanks.

By: cipriano

cipriano — Fri, 20 Nov 2009 01:54:34 +0000

Great post for someone that isn’t new to programming, but new to ruby. I still don’t understand the reason to write code this way, but I think that will become more apparent as I learn more about Ruby. Thanks!

By: Peter

Peter — Thu, 20 Aug 2009 15:27:48 +0000

Thanks; definitely the best summary I’ve found. Either that, or my background on this stuff finally got to the point where it all makes sense when I see it written out .

Wanted to second the point of Coffee_fan above; you don’t use return to get out of blocks (unless you actually want to pop out of the enclosing method), but you can use break or next. These are useful in different situations. Also, break and next can both take arguments to return to the outer context, just like return.

@elliottcable:

By: Biju Subhash

Biju Subhash — Sat, 27 Dec 2008 07:58:43 +0000

Nice Post
Thank You

By: Brian

Brian — Thu, 12 Jun 2008 15:32:26 +0000

Great article. Really cleared up a lot of my understanding about this topic!

By: Andriy

Andriy — Tue, 26 Feb 2008 01:39:14 +0000

Great explanation. Finally i understand “how” yield works.

By: Deepak Gole

Deepak Gole — Tue, 15 Jan 2008 07:28:30 +0000

Hello If I want pass arguments to method (&:center), then how to send it
class Symbol

# A generalized conversion of a method name
# to a proc that runs this method.
#
def to_proc
lambda {|x, *args| x.send(self, *args)}
end

end

# Viola !
words = %w(Jane, aara, multiko)
upcase_words = words.map(&:center)

By: cks2k2

cks2k2 — Mon, 10 Dec 2007 06:10:37 +0000

# this doesn’t (ArgumentError), because &f
# isn’t really an argument – it’s only there
# to convert a block
contrived(25, lambda {|x| puts x})

I tried this on 1.8.6-25 but getting an ArgumentError(2 for 1).
Or am I the only getting this error?
I’ve tried contrived( 25, Proc.new {|x| puts x}) but it’s still not working.

By: elliottcable

elliottcable — Tue, 27 Nov 2007 21:44:15 +0000

In addition to being way cooler a whopping two characters shorter

Or, if you’re really awesomely cool, you could do this instead:
module Kernel alias λ proc # (U+03BB) end

padd = λ {|x, y| puts x + y} padd.call