From: Rick DeNatale <rick.denatale@...>
Date: 2007-10-22T10:30:34+09:00
Subject: Re: gsub does not work with do/end block, only brackets

On 10/21/07, Michael Chow <nanostuff@magma.ca> wrote:
> puts "abcdefg".gsub(/abc/) do |x|
>   x.upcase
> end
>
> ^This does not work. ArgumentError, it's expecting the second argument
> that's required when a block is not provided.
>
> puts "abcdefg".gsub(/abc/) { |x|
>   x.upcase
> }
>
> ^This works.
>
> Why??

Because {} binds tighter than do end

puts "abcdefg".gsub(/abc/) do |x|
   x.upcase
end

Is parsed as:

> puts "abcdefg".gsub(/abc/) { |x|
>   x.upcase
> }
>
> ^This works.
>
> Why??

Because {} binds tighter than do end

(puts ("abcdefg".gsub(/abc/))) do |x|
   x.upcase
end

Which means that the block is associated with the call to puts rather than gsub.

While

puts "abcdefg".gsub(/abc/) { |x|
   x.upcase
\ }

Is parsed as

puts ("abcdefg".gsub(/abc/) { |x|
   x.upcase
\ })
-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/