Introduce list format option.

The `ls` output can be customized with the list_format option in the
configuration, or the `-F` flag for `ls`.

Open issues:

* Relative dates to be implemented (see PR #52)
* Using (%p) without todo items without priority results in ()
* Ability to print todo on a single line (see PR #52)

topydo.conf

@@ -15,6 +15,7 @@ auto_creation_date          = 1
 hide_tags                   = id,p,ical
 indent                      = 0
 list_limit                  = -1
+list_format                 = |%i| (%p) %s
 
 [tags]
 tag_start                   = t

topydo/commands/ListCommand.py

@@ -20,7 +20,8 @@ from topydo.lib.IcalPrinter import IcalPrinter
 from topydo.lib.JsonPrinter import JsonPrinter
 from topydo.lib.PrettyPrinter import pretty_printer_factory
 from topydo.lib.PrettyPrinterFilter import (PrettyPrinterHideTagFilter,
-                                            PrettyPrinterIndentFilter)
+                                            PrettyPrinterIndentFilter,
+                                            PrettyPrinterFormatFilter)
 
 
 class ListCommand(ExpressionCommand):
@@ -34,6 +35,7 @@ class ListCommand(ExpressionCommand):
         self.printer = None
         self.sort_expression = config().sort_string()
         self.show_all = False
+        self.format = config().list_format()
 
     def _poke_icalendar(self):
         """
@@ -49,7 +51,7 @@ class ListCommand(ExpressionCommand):
         return True
 
     def _process_flags(self):
-        opts, args = self.getopt('f:s:x')
+        opts, args = self.getopt('f:F:s:x')
 
         for opt, value in opts:
             if opt == '-x':
@@ -64,6 +66,8 @@ class ListCommand(ExpressionCommand):
                         self.printer = IcalPrinter(self.todolist)
                 else:
                     self.printer = None
+            elif opt == '-F':
+                self.format = value
 
         self.args = args
 
@@ -81,6 +85,8 @@ class ListCommand(ExpressionCommand):
             hidden_tags = config().hidden_tags()
 
             filters = []
+            filters.append(PrettyPrinterFormatFilter(self.todolist,
+                           self.format))
             filters.append(PrettyPrinterIndentFilter(indent))
             filters.append(PrettyPrinterHideTagFilter(hidden_tags))
 

topydo/lib/Config.py

@@ -69,6 +69,7 @@ class _Config:
                 'hide_tags': 'id,p,ical',
                 'indent': '0',
                 'list_limit': '-1',
+                'list_format': '|%i| (%p) %s',
             },
 
             'tags': {
@@ -307,6 +308,11 @@ class _Config:
 
         return alias_dict
 
+    def list_format(self):
+        """ Returns the list format used by `ls` """
+        return self.cp.get('ls', 'list_format')
+
+
 def config(p_path=None, p_overrides=None):
     """
     Retrieve the config instance.

topydo/lib/PrettyPrinterFilter.py

@@ -125,3 +125,55 @@ class PrettyPrinterHideTagFilter(PrettyPrinterFilter):
                                 p_todo_str)
 
         return p_todo_str
+
+
+class PrettyPrinterFormatFilter(PrettyPrinterFilter):
+    def __init__(self, p_todolist, p_format=None):
+        super(PrettyPrinterFormatFilter, self).__init__()
+        self.todolist = p_todolist
+        self.format = p_format or config().list_format()
+
+    def filter(self, p_todo_str, p_todo):
+        placeholders = {
+            # absolute creation date
+            'c': lambda t: t.creation_date().isoformat() if t.creation_date() else '',
+
+            # relative creation date
+            'C': lambda t: '#', # TODO: humanized creation date
+
+            # absolute due date
+            'd': lambda t: t.due_date().isoformat() if t.due_date() else '',
+
+            # relative due date
+            'D': lambda t: '#', # TODO: humanized due date
+
+            # todo ID
+            'i': lambda t: str(self.todolist.number(t)),
+
+            # list of tags (spaces)
+            'K': lambda t: ' '.join(['{}:{}'.format(tag, value)
+                                     for tag, value in sorted(p_todo.tags())]),
+
+            # priority
+            'p': lambda t: t.priority() if t.priority() else '',
+
+            # text
+            's': lambda t: t.text(),
+
+            # absolute start date
+            't': lambda t: t.start_date().isoformat() if t.start_date() else '',
+
+            # relative start date
+            'T': lambda t: '#', # TODO: humanized start date
+
+            # literal %
+            '%': lambda _: '%',
+        }
+
+        p_todo_str = self.format
+
+        for placeholder, getter in placeholders.items():
+            p_todo_str = re.sub(r'%\[?{}\]?'.format(placeholder), getter(p_todo), p_todo_str)
+
+        return p_todo_str
+