From: roob noob <lists@...>
Date: 2012-07-20T13:05:38+09:00
Subject: unless if not == unless post_on_ruby_forum

So everything I have thus far read and heard about the Ruby unless
keyword lead me to believe that it is just another word for if not. This
is not true.

 unless 1 + 1 == 2
   puts "a"
 elsif 1 + 1 == 5
   puts "b"
 else
   puts "c"
 end

this code fails and complains that it expects an end to be where elsif
is
however

 if not 1 + 1 == 2
   puts "a"
 elsif 1 + 1 == 5
   puts "b"
 else
   puts "c"
 end

works as expected. This took me quite a while to figure out as everyone
had always lead me to believe that unless is just the cool kids way of
saying if not in ruby.

So I guess my question is, are there any other unexpected behaviors of
unless that I should know about? I think I might just start using if not
and ignoring unless, I actually end up having to translate it to if not
in my head anyway to read things clearly, and it doesn't work with
elsif. Why does everyone rave about how unless is exactly like if not
but with clearer language, if this is not the case ?

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