Bug #14935: Inconsitent behaviour with puts and enumerator with different block format.

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin16]
• Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN

[[e-mail] (Puneet Sutar)]

Case: 1

➜  ~ ruby
puts [1,2,3].map do |i|
  puts i
end
#<Enumerator:0x007ffe930b76d0>
➜  ~
# block does get evaluated.

Case 2:

➜  ~ ruby
puts [1, 2, 3].map { |i| puts i }
1
2
3



➜  ~
# Block gets evaluated. 

My question is Shouldn't both cases give consistent output.

[shan (Shannon Skipper)]

#puts returns nil, so when you're mapping you end up with [nil, nil, nil], which prints with #puts as three blank lines. If you use p instead of puts inside the block, the block will return i instead of nil and you'll see the same output.

[lucasbuchala (Lucas Buchala)]

I think this is because do ... end blocks has lower precedence than {...} blocks. As documented in [1]. So, probably, not a bug.

method1 method2 { ... }     # method2's block
method1 method2 do ... end  # method1's block

[1] http://ruby-doc.org/core-2.5.1/doc/syntax/calling_methods_rdoc.html#label-Block+Argument

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Rejected