Examples of Ruby hoisting variables

hoisting.rb

# generic hoisting
if true
  a = 1
end
a # => 1


begin
  b = 2
end
b # => 2


for whatevz in [1, 2]
  c = 3
end
c # => 3


# multi-level hoisting
if true
  if true
    if true
      d = 4
    end
  end
end
d # => 4


if false
  if false
    if false
      e = 5
    end
  end
end
e # => nil


# Ruby's multiline if statement hoists, but its inline one doesn't, inconsistent enough to seem like a bug:
if f = 'F'
  f # => "F"
end
f # => "F"

g if g = 'B' # => NameError: undefined local variable or method `g' for main:Object

# ~> NameError
# ~> undefined local variable or method `g' for main:Object
# ~>
# ~> /var/folders/7g/mbft22555w3_2nqs_h1kbglw0000gn/T/seeing_is_believing_temp_dir20150323-47469-1c0cwrl/program.rb:47:in `<main>'

i total agree with you @baldwindavid

Yeah, this is different than JavaScript hoisting (confusing nonetheless).

Also, let me increase confusion by a little bit :)

g if g = 'B' # => NameError: undefined local variable or method `g' for main:Object
g # => "B"

# or, in a .rb file rather than irb/pry
begin
  g if g = 'B'
rescue => e
  p g # => "B"
  raise e
end