added docs for Base.cache :if.

CHANGES.textile

@@ -3,6 +3,9 @@ h2. 3.6.5
 h3. Bugfixes
   * `Cell::TestCase#invoke` now properly accepts state-args.
 
+h3. Changes
+  * Added the `:if` option to `Base.cache` which allows adding a conditional proc or instance method to the cache definition. If it doesn't return true, caching for that state is skipped. 
+
 
 h2. 3.6.4
 

lib/cell/caching.rb

@@ -19,6 +19,11 @@ module ClassMethods
       #
       #   cache :show, :expires_in => 10.minutes
       #
+      # The +:if+ option lets you define a conditional proc or instance method. If it doesn't
+      # return a true value, caching for that state is skipped.
+      #
+      #   cache :show, :if => proc { |cell, options| options[:enable_cache] }
+      #
       # If you need your own granular cache keys, pass a versioner block.
       #
       #   cache :show do |cell, options|
@@ -112,12 +117,12 @@ def call_proc_or_method(state, method, *args)
 
     def call_state_versioner(state, *args)
       method = self.class.version_procs[state] or return
-      call_proc_or_method state, method, *args
+      call_proc_or_method(state, method, *args)
     end
 
     def call_state_conditional(state, *args)
       method = self.class.conditional_procs[state] or return true
-      call_proc_or_method state, method, *args
+      call_proc_or_method(state, method, *args)
     end
 
   end