adding body-less while expressions

examples/poignant.coffee

@@ -14,9 +14,9 @@
 # end
 
 LotteryTicket: {
-  get_picks:    => this.picks
-  set_picks:    nums => this.picks: nums
-  get_purchase: => this.purchase
+  get_picks:           => this.picks
+  set_picks:      nums => this.picks: nums
+  get_purchase:        => this.purchase
   set_purchase: amount => this.purchase: amount
 }
 

lib/coffee_script/grammar.y

@@ -340,6 +340,7 @@ rule
   # The while loop. (there is no do..while).
   While:
     WHILE Expression Block            { result = WhileNode.new(val[1], val[2]) }
+  | WHILE Expression                  { result = WhileNode.new(val[1], nil) }
   ;
 
   # Array comprehensions, including guard and current index.

lib/coffee_script/nodes.rb

@@ -609,6 +609,7 @@ module CoffeeScript
       o[:top]     = true
       cond        = @condition.compile(o)
       post        = returns ? "\n#{idt}return null;" : ''
+      return write("#{idt}while (#{cond});#{post}") if @body.nil?
       write("#{idt}while (#{cond}) {\n#{@body.compile(o)}\n#{idt}}#{post}")
     end
   end