Apparently it's Bool, not Boolean...

Author: TeaSeaLancs

lib/sassc/script.rb

@@ -39,5 +39,5 @@ module Script
 SassC::Script::Color = Sass::Script::Value::Color
 SassC::Script::Value::Color = Sass::Script::Value::Color
 
-SassC::Script::Boolean = Sass::Script::Value::Boolean
-SassC::Script::Value::Boolean = Sass::Script::Value::Boolean
+SassC::Script::Bool = Sass::Script::Value::Bool
+SassC::Script::Value::Bool = Sass::Script::Value::Bool

lib/sassc/script/value_conversion.rb

@@ -13,7 +13,7 @@ def self.from_native(native_value, options)
           argument
         when :sass_boolean
           value = Native.boolean_get_value(native_value)
-          argument = Script::Boolean.new(value)
+          argument = Script::Bool.new(value)
 
           argument
         when :sass_number

lib/sassc/script/value_conversion/boolean.rb renamed to lib/sassc/script/value_conversion/bool.rb

@@ -1,7 +1,7 @@
 module SassC
   module Script
     module ValueConversion
-      class Boolean < Base
+      class Bool < Base
         def to_native
           Native::make_boolean(@value.value)
         end