ENH: Added a register function to extend command list.

pptgen/__init__.py

@@ -101,6 +101,21 @@ def replicate_slides(data, prs, change, slide, slides_to_remove, index):
     copy_slide = None
 
 
+def register(config):
+    """Function to register a new `command` to command list."""
+    global COMMANDS_LIST
+    if 'register' in config:
+        resister_command = config.pop('register')
+        if not isinstance(resister_command, (dict,)):
+            raise NotImplementedError()
+        for command_name, command_function in resister_command.items():
+            if command_name not in COMMANDS_LIST:
+                if not isinstance(command_function, (dict,)):
+                    command_function = {'function': command_function}
+                _vars = {'shape': None, 'spec': None, 'data': None}
+                COMMANDS_LIST[command_name] = build_transform(command_function, vars=_vars)
+
+
 def pptgen(source, target, **config):
     '''
     Process a configuration. This loads a Presentation from source, applies the
@@ -108,8 +123,6 @@ def pptgen(source, target, **config):
     '''
     # Config was being over written using PPTXHandler and data key was being
     # removed from yaml config.
-    global COMMANDS_LIST
-
     handler = config.pop('handler') if 'handler' in config else None
     _config = copy.deepcopy(config)
     if _config.get('is_formhandler', False):
@@ -117,17 +130,6 @@ def pptgen(source, target, **config):
         _config.pop('is_formhandler')
     else:
         data = AttrDict(load_data(_config.pop('data', {}), handler=handler))
-
-    if 'register' in _config:
-        resister_command = _config.pop('register')
-        if not(isinstance(resister_command), (dict),):
-            raise NotImplementedError()
-        for command_name, command_function in resister_command.items():
-            if command_name not in COMMANDS_LIST:
-                if not isinstance(command_function, (dict,)):
-                    command_function = {'function': command_function}
-                COMMANDS_LIST[command_name] = build_transform(command_function)[0]
-
     prs = Presentation(source)
     slides = prs.slides
     # Loop through each change configuration
@@ -136,6 +138,7 @@ def pptgen(source, target, **config):
 
     for key, change in _config.items():
         # Apply it to every slide
+        register(change)
         slide_data = copy.deepcopy(data)
         slide_data['handler'] = handler
         if 'data' in change and change['data'] is not None:
@@ -236,6 +239,5 @@ def change_shapes(collection, change, data, **kwargs):
         for cmd, method in COMMANDS_LIST.items():
             if cmd in spec:
                 method(shape, spec, shape_data)
-
         commands.copy_slide_elem(shape, dest)
     commands.add_new_slide(dest, source_slide)