silenced "already initialized constant" warnings

lib/json/common.rb

@@ -49,6 +49,7 @@ def deep_const_get(path) # :nodoc:
 
     # Set the module _generator_ to be used by JSON.
     def generator=(generator) # :nodoc:
+      old, $VERBOSE = $VERBOSE, nil
       @generator = generator
       generator_methods = generator::GeneratorMethods
       for const in generator_methods.constants
@@ -77,6 +78,8 @@ def generator=(generator) # :nodoc:
         :object_nl      => "\n",
         :array_nl       => "\n"
       )
+    ensure
+      $VERBOSE = old
     end
 
     # Returns the JSON generator modul, that is used by JSON. This might be

lib/json/ext.rb

@@ -11,5 +11,5 @@ module Ext
     JSON.generator = Generator
   end
 
-  JSON_LOADED = true
+  JSON_LOADED = true unless const_defined?(:JSON_LOADED)
 end

lib/json/pure.rb

@@ -73,5 +73,5 @@ module Pure
     JSON.generator = Generator
   end
 
-  JSON_LOADED = true
+  JSON_LOADED = true unless const_defined?(:JSON_LOADED)
 end