lib/iruby.rb in iruby-0.3 vs lib/iruby.rb in iruby-0.4.0

@@ -2,29 +2,35 @@
 require 'multi_json'
 require 'securerandom'
 require 'openssl'
 require 'tempfile'
 require 'set'
+
 require 'iruby/version'
+require 'iruby/jupyter'
 require 'iruby/kernel'
 require 'iruby/backend'
 require 'iruby/ostream'
 require 'iruby/input'
 require 'iruby/formatter'
 require 'iruby/utils'
 require 'iruby/display'
 require 'iruby/comm'
-require 'iruby/session/mixin'
 
-begin
-  require 'iruby/session/cztop'
-rescue LoadError
+if ENV.fetch('IRUBY_OLD_SESSION', false)
+  require 'iruby/session/mixin'
   begin
-    require 'iruby/session/rbczmq'
+    require 'iruby/session/ffi_rzmq'
   rescue LoadError
     begin
-      require 'iruby/session/ffi_rzmq'
+      require 'iruby/session/cztop'
     rescue LoadError
-      STDERR.puts "You should install cztop, rbczmq or ffi_rzmq before running iruby notebook. See README."
+      begin
+        require 'iruby/session/rbczmq'
+      rescue LoadError
+        STDERR.puts "You should install ffi-rzmq, cztop, or rbczmq before running iruby notebook. See README."
+      end
     end
   end
+else
+  require 'iruby/session'
 end