Add Info operations family and start with GetColumnType

PyRDF/Operation.py

@@ -32,7 +32,7 @@ class Operation(object):
         print(PyRDF.current_backend.supported_operations)
     """
 
-    Types = Enum("Types", "ACTION TRANSFORMATION INSTANT_ACTION")
+    Types = Enum("Types", "ACTION TRANSFORMATION INSTANT_ACTION INFO")
 
     def __init__(self, name, *args, **kwargs):
         """
@@ -80,7 +80,15 @@ def _classify_operation(self, name):
             'Take': ops.ACTION,
             'Graph': ops.ACTION,
             'Snapshot': ops.INSTANT_ACTION,
-            'Foreach': ops.INSTANT_ACTION
+            'Foreach': ops.INSTANT_ACTION,
+            'Alias': ops.INFO,
+            'GetColumnNames': ops.INFO,
+            'GetDefinedColumnNames': ops.INFO,
+            'GetColumnType': ops.INFO,
+            'GetColumnTypeNamesList': ops.INFO,
+            'GetFilterNames': ops.INFO,
+            'Display': ops.INFO,
+            'SaveGraph': ops.INFO
         }
 
         op_type = operations_dict.get(name)
@@ -107,3 +115,13 @@ def is_transformation(self):
             False otherwise.
         """
         return self.op_type == Operation.Types.TRANSFORMATION
+
+    def is_info(self):
+        """
+        Checks if the current operation is an info.
+
+        Returns:
+            bool: True if the current operation is an info,
+            False otherwise.
+        """
+        return self.op_type == Operation.Types.INFO

PyRDF/Proxy.py

@@ -3,6 +3,7 @@
 from abc import ABCMeta, abstractmethod
 from PyRDF.Operation import Operation
 from PyRDF.Node import Node
+import ROOT
 # Abstract class declaration
 # This ensures compatibility between Python 2 and 3 versions, since in
 # Python 2 there is no ABC class
@@ -89,6 +90,28 @@ def _call_action_result(self, *args, **kwargs):
         return getattr(self.GetValue(), self._cur_attr)(*args, **kwargs)
 
 
+def _trigger_info_operation(node, op, *args, **kwargs):
+    """
+    Function to retrieve the PyROOT node objects defined by the user
+    up to the point of calling an Info operation. This function triggers the
+    creation of PyROOT objects in order to call the ROOT function issued by the
+    user.
+    """
+    generator = CallableGenerator(node.get_head())
+
+    mapper = generator.get_callable()  # Get the callable
+
+    # Create a PyROOT RDataFrame
+    pyroot_rdf = ROOT.ROOT.RDataFrame(*generator.head_node.args)
+
+    # Execute the mapper function
+    mapper(pyroot_rdf)
+
+    # Call the function on the PyROOT object with the arguments provided by
+    # the user.
+    return getattr(node.pyroot_node, op.name)(*args, **kwargs)
+
+
 class TransformationProxy(Proxy):
     """
     A proxy object to an non-action node. It implements acces to attributes
@@ -133,8 +156,15 @@ def _create_new_op(self, *args, **kwargs):
         # Add the new node as a child of the current node
         self.proxied_node.children.append(newNode)
 
-        # Return the appropriate proxy object for the node
+        # Behave accordingly to the type of the operation
         if op.is_action():
             return ActionProxy(newNode)
+        elif op.is_info():
+            return _trigger_info_operation(
+                self.proxied_node,
+                op,
+                *args,
+                **kwargs
+            )
         else:
             return TransformationProxy(newNode)

PyRDF/backend/Backend.py

@@ -40,7 +40,15 @@ class Backend(ABC):
         'Foreach',
         'Reduce',
         'Aggregate',
-        'Graph'
+        'Graph',
+        'Alias',
+        'GetColumnNames',
+        'GetDefinedColumnNames',
+        'GetColumnType',
+        'GetColumnTypeNamesList',
+        'GetFilterNames',
+        'Display',
+        'SaveGraph'
     ]
 
     initialization = staticmethod(lambda: None)

PyRDF/backend/Local.py

@@ -28,6 +28,14 @@ def __init__(self, config={}):
             'Foreach',
             'Reduce',
             'Aggregate',
+            'Alias',
+            'GetColumnNames',
+            'GetDefinedColumnNames',
+            # 'GetColumnType',
+            'GetColumnTypeNamesList',
+            'GetFilterNames',
+            'Display',
+            'SaveGraph'
         ]
         if ROOT.ROOT.IsImplicitMTEnabled():
             # Add `Range` operation only if multi-threading