Allow actions on multiple ids without MultiCommand

This feature means that commands like `tag`, `append` or `dep` can work
now with multiple (marked) todo items in column UI.

topydo/ui/columns/Main.py

@@ -38,6 +38,7 @@ from topydo.ui.columns.ConsoleWidget import ConsoleWidget
 from topydo.ui.columns.KeystateWidget import KeystateWidget
 from topydo.ui.columns.TodoWidget import TodoWidget
 from topydo.ui.columns.TodoListWidget import TodoListWidget
+from topydo.ui.columns.Transaction import Transaction
 from topydo.ui.columns.Utils import PaletteItem, to_urwid_color
 from topydo.ui.columns.ViewWidget import ViewWidget
 from topydo.ui.columns.ColumnLayout import columns
@@ -269,11 +270,6 @@ class UIApplication(CLIApplicationBase):
 
         self._last_cmd = (p_command, p_output == self._output)
 
-        if '{}' in p_command:
-            if self._has_marked_todos():
-                p_todo_id = ' '.join(self.marked_todos)
-            p_command = p_command.format(p_todo_id)
-
         try:
             p_command = shlex.split(p_command)
         except ValueError as verr:
@@ -281,24 +277,30 @@ class UIApplication(CLIApplicationBase):
             return
 
         try:
-            (subcommand, args) = get_subcommand(p_command)
+            subcommand, args = get_subcommand(p_command)
         except ConfigError as cerr:
             self._print_to_console(
                 'Error: {}. Check your aliases configuration.'.format(cerr))
             return
 
-        self._backup(subcommand, args)
+        env_args = (self.todolist, p_output, self._output, self._input)
+        ids = None
+
+        if '{}' in args:
+            ids = self.marked_todos if self._has_marked_todos() else [p_todo_id]
+
+        transaction = Transaction(subcommand, env_args, ids)
+        transaction.prepare(args)
 
         try:
-            command = subcommand(
-                args,
-                self.todolist,
-                p_output,
-                self._output,
-                self._input,
-            )
+            self._backup(subcommand, args)
+        except TypeError:
+            self._print_to_console('Error: no todo item was marked for this'
+                                   ' action.')
+            return
 
-            if command.execute() != False:
+        try:
+            if transaction.execute():
                 self._post_execute()
 
         except TypeError:

topydo/ui/columns/Transaction.py

+# Topydo - A todo.txt client written in Python.
+# Copyright (C) 2017 Bram Schoenmakers <bram@topydo.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from topydo.lib.MultiCommand import MultiCommand
+
+
+class Transaction(object):
+    """
+    This class implements basic handling of executing any subcommand on multiple
+    todo items.
+    """
+    def __init__(self, p_subcommand=None, p_env_args=(), p_todo_ids=None):
+        self._multi = issubclass(p_subcommand, MultiCommand)
+        self._cmd = lambda op: p_subcommand(op, *p_env_args)
+        self._todo_ids = p_todo_ids
+        self._operations = []
+
+    def prepare(self, p_args):
+        """
+        Prepares list of operations to execute based on p_args, list of
+        todo items contained in _todo_ids attribute and _subcommand
+        attribute.
+        """
+        if self._todo_ids:
+            id_position = p_args.index('{}')
+
+            # Not using MultiCommand abilities would make EditCommand awkward
+            if self._multi:
+                p_args[id_position:id_position + 1] = self._todo_ids
+                self._operations.append(p_args)
+            else:
+                for todo_id in self._todo_ids:
+                    operation_args = p_args[:]
+                    operation_args[id_position] = todo_id
+                    self._operations.append(operation_args)
+        else:
+            self._operations.append(p_args)
+
+    def execute(self):
+        """
+        Executes each operation from _operations attribute.
+        """
+        last_operation = len(self._operations) - 1
+        for i, operation in enumerate(self._operations):
+            command = self._cmd(operation)
+
+            if command.execute() is False:
+                return False
+            elif i == last_operation:
+                return True