From: Hugh Sasse Staff Elec Eng <hgs@...>
Date: 2002-07-10T18:36:32+09:00
Subject: Case expressions and LHS of assignment....

While trying to avoid Repetition in my code I tried to rewrite a case
statement, thinking how they can be used on the right hand side of an
assignment, so I tried the left hand side.  It basically came down to
this:

#!/usr/local/bin/ruby -w

class Lvalue
   def initialize
      @a = @b = @c = "initial"
   end
   def assign(x,y)
      (case x
       when 1
          @a
       when 2
          @b
       when 3
          @c
       end) = y
   end
end

lvalue = Lvalue.new
lvalue.assig(2,"Different")
p lvalue

__END__
but this gives:

/home/hgs/progs/ruby/lvalue1.rb:15: parse error
       end) = y
             ^

I tried leaving the () off too.  I was not really surprised when it
failed, but I was left wondering about it.  In an ideal world is this
desirable, or is it complicating things too much?  I bet it would
complicate the parser. Is it even sensible?

This might not lead to Repetition, but may lead to Deviation
(http://www.bbc.co.uk/radio4/comedy/justaminute.shtml)!

        Hugh (possibly thinking too far outside the box!)