Ruby and Chef Syntax - Learning Chef - page 62

iif false
puts "this can't possibly happen"
elsif elsif nil

puts "this won't happen either"
elsif elsif true

puts "this will definitely happen"
else

else
puts "this won't happen, because the method is short-circuited
end

If the result of an expression is falsey, the body of that block will not be executed.

ni l is considered a falsey value, so this block will not be evaluated.

Be cause the former elsif block will always execute, this else block is unnecessary.

Less common in Ruby (but common in Chef) is the case statement. Very similar to the
if statement, the case statement applies more syntactic sugar and logic for the deve-
loper:

case case some_condition

when

when "literal string"
# ...
when when /regular expression/

# ...
when when list , of , items

# ...
else

else
# ...
end end

If a literal object is supplied, the case statement will perform a pure equality match.

If a regular expression is supplied, Ruby will attempt to call match on the receiving ob-
ject.

If multiple items are given, they are interpreted as “or” (if the item matches “list”, “of”,
or “items”).