erp5_data_notebook bt5: Use interactivity/mode and finally execute all code...

erp5_data_notebook bt5: Use interactivity/mode and finally execute all code using exec to get rid of try:except

bt5/erp5_data_notebook/ExtensionTemplateItem/portal_components/extension.erp5.JupyterCompile.py

@@ -4,12 +4,30 @@ from StringIO import StringIO
 from Products.ERP5Type.Globals import  PersistentMapping
 
 import sys
+import ast
 
 def Base_compileJupyterCode(self, jupyter_code, old_local_variable_dict):
   """
     Function to execute jupyter code and update the local_varibale dictionary.
-    It also handles the exception raised, catch them and return them as a python
-    dictionary. Use of eval for expressions and exec for statements
+    Code execution depends on 'interactivity', a.k.a , if the ast.node object has
+    ast.Expr instance(valid for expressions) or not.
+
+    The behaviour would be similar to that of jupyter notebook:-
+    ( https://github.com/ipython/ipython/blob/master/IPython/core/interactiveshell.py#L2954 )
+    Example:
+
+      code1 = '''
+      23
+      print 23 #Last node not an expression, interactivity = 'last'
+      '''
+      out1 = '23'
+
+      code2 = '''
+      123
+      12 #Last node an expression, interactivity = 'none'
+      '''
+      out2 = '12'
+
   """
   # Other way would be to use all the globals variables instead of just an empty
   # dictionary, but that might hamper the speed of exec or eval.
@@ -31,39 +49,54 @@ def Base_compileJupyterCode(self, jupyter_code, old_local_variable_dict):
   # catching errors on server/erp5.
   status = u'ok'
 
-  # eval used before exec because exec can handle the error raised by both eval
-  # and exec. Example to explain execution :-
-  # code        eval_result      eval_error     exec_result       exec_error
-  # =======================================================================
-  # print 42    None            Syntax Error     42                None
-  # 42          42              None             None              None
-  # abc         None            Name Error       None              Name Error
-  # a=42;print ab None          Syntax Error     None              Name Error
-  # From above, it infers that the invalid syntax is being handled by exec only
-  try:
-    jupyter_compiled = compile(jupyter_code, '<string>', 'eval')
-    eval_result = eval(jupyter_compiled, g, g)
-    result_string = str(eval_result)
-  # Trying to catch everything which results in error from eval
-  # It can be just an invalid syntax, invalid expression or some error
-
-  except Exception:
-    # Returning the printed statement from exec using sys.stdout
-    # Catching the executed output and saving it in a variable
+  # Execute only if jupyter_code is not empty
+  if jupyter_code:
+    # Create ast parse tree
+    ast_node = ast.parse(jupyter_code)
+    # Get the node list from the parsed tree
+    nodelist = ast_node.body
+
+    # If the last node is instance of ast.Expr, set its interactivity as 'last'
+    # This would be the case if the last node is expression
+    if isinstance(nodelist[-1], ast.Expr):
+      interactivity = "last"
+    else:
+      interactivity = "none"
+
+    # Here, we define which nodes to execute with 'single' and which to execute
+    # with 'exec' mode.
+    if interactivity == 'none':
+      to_run_exec, to_run_interactive = nodelist, []
+    elif interactivity == 'last':
+      to_run_exec, to_run_interactive = nodelist[:-1], nodelist[-1:]
+
     old_stdout = sys.stdout
     result = StringIO()
     sys.stdout = result
 
+    # Execute the nodes with 'exec' mode
+    for node in to_run_exec:
+      mod = ast.Module([node])
+      code = compile(mod, '<string>', "exec")
+      exec(code, g, g)
+
+    # Execute the interactive nodes with 'single' mode
+    for node in to_run_interactive:
+      mod = ast.Interactive([node])
+      code = compile(mod, '<string>', "single")
+      exec(code, g, g)
+
     # Letting the code fail in case of error while executing the python script/code
     # XXX: Need to be refactored so to acclimitize transactions failure as well as
     # normal python code failure and show it to user on jupyter frontend.
     # Decided to let this fail silently in backend without letting the frontend
     # user know the error so as to let tranasction or its error be handled by ZODB
     # in uniform way instead of just using half transactions.
-    jupyter_compiled = compile(jupyter_code, '<string>', 'exec')
-    exec(jupyter_compiled, g, g)
+
     sys.stdout = old_stdout
     result_string = result.getvalue()
+  else:
+    result_string = jupyter_code
 
   # Difference between the globals variable before and after exec/eval so that
   # we don't have to save unnecessary variables in database which might or might

bt5/erp5_data_notebook/ExtensionTemplateItem/portal_components/extension.erp5.JupyterCompile.xml

@@ -46,8 +46,8 @@
             <key> <string>text_content_warning_message</string> </key>
             <value>
               <tuple>
-                <string>W: 45, 18: Use of eval (eval-used)</string>
-                <string>W: 64,  4: Use of exec (exec-used)</string>
+                <string>W: 81,  6: Use of exec (exec-used)</string>
+                <string>W: 87,  6: Use of exec (exec-used)</string>
               </tuple>
             </value>
         </item>