From: William James <w_a_x_man@...>
Date: 2005-09-01T08:26:24+09:00
Subject: Re: Semantics of << and <<-

Anders H�ckersten wrote:
> Hi,
> I recently joined this list, so please forgive me if this question has
> been asked recently. I am wondering about the precise semantics of <<
> and <<-. "Programming Ruby"[1] and the pseudo-BNFs[2][3] say that you
> can use a quoted string after <<. As I see it, this means I should be
> able to able to use the #{expr} construct inside this string, like this:
> print <<"#{2+2}"
> foobar
> #{4}

The purpose of quoting the here-document label is to make the
text be treated as though it were enclosed in single quotes.
----------------------------------------------
puts <<'HERE'
#{3**3} bells.
HERE

puts <<"HERE"
#{3**3} bells.
HERE

puts <<HERE
#{3**3} bells.
HERE
------------------------------------------------

#{3**3} bells.
27 bells.
27 bells.