<< could be used as heredoc.

[Billy.Zheng]

valid:

def test_heredoc
    <<HEREDOC
      Subscription expiring soon!
HEREDOC
end

invalid:

def test_heredoc
    <<HEREDOC
      Subscription expiring soon!
    HEREDOC
end

puts test_heredoc

valid:

def test_heredoc
    <<-HEREDOC
      Subscription expiring soon!
    HEREDOC
end

puts test_heredoc

BTW: for the integrality, why not plus sign and minus sign ??

[Billy.Zheng]

supplement:

"#{}" in many language, e.g. lisp, bash shell, named: String interpolation

[Juanito Fatas]

please help send pull request :)