Initial commit.

Wrote the base class that represents a single todo item.

Todo.py

+"""
+This module contains the class that represents a single todo item.
+"""
+
+import re
+
+import TodoParser
+
+class Todo(object):
+    """
+    This class represents a single todo item in a todo.txt file. It maintains
+    an internal data dictionary of various attributes, but also keeps the plain
+    text format in shape such that it can be printed back to a file with as few
+    distortions as possible (no re-shuffling of attributes).
+    """
+
+    src = None
+    fields = {}
+
+    def __init__(self, p_src):
+        self.src = p_src
+        self.fields = TodoParser.parse_line(p_src)
+
+    def tag_value(self, p_key):
+        """
+        Returns a tag value associated with p_key. Returns None if p_key
+        does not exist.
+        """
+        values = self.tag_values(p_key)
+        return values[0] if len(values) else None
+
+    def tag_values(self, p_key):
+        """ Returns a list of all tag values associated with p_key. Returns
+        empty list if p_key does not exist. """
+
+        tags = self.fields['tags']
+        matches = [tag[1] for tag in tags if tag[0] == p_key]
+        return matches if len(matches) else []
+
+    def has_tag(self, p_key):
+        """
+        Returns true iff this todo has at least one tag with the given key.
+        """
+        return len(self.tag_values(p_key)) > 0
+
+    def set_tag(self, p_key, p_value=""):
+        """
+        Sets a occurrence of the tag identified by p_key. Sets an arbitrary
+        instance of the tag when the todo contains multiple tags with this key.
+        When p_key does not exist, the tag is added.
+
+        When p_value is not set, the tag will be removed.
+        """
+
+        if p_value == "":
+            self.remove_tag(p_key)
+            return
+
+        value = self.tag_value(p_key)
+        if value:
+            # remove old value from the tags
+            self.fields['tags'] = [t for t in self.fields['tags'] \
+                if t[0] != p_key and t[1] != value]
+
+            self.src = re.sub(
+                r'\b' + p_key + ':' + value + r'\b',
+                p_key + ':' + p_value,
+                self.src
+            )
+        else:
+            self.src += ' ' + p_key + ':' + p_value
+
+        self.fields['tags'].append((p_key, p_value))
+
+    def remove_tag(self, p_key, p_value=""):
+        """
+        Removes a tag from the todo.
+        When the value is empty (default), all occurrences of the tag will be
+        removed.
+        Else, only those tags with the value will be removed.
+        """
+
+        # Build a new list that excludes the specified tag, match by value when
+        # p_value is given.
+        self.fields['tags'] = [t for t in self.fields['tags'] \
+            if not (t[0] == p_key and (p_value == "" or t[1] == p_value))]
+
+        # when value == "", match any value having key p_key
+        value = p_value if p_value != "" else r'\S+'
+        self.src = re.sub(r'\s?' + p_key + ':' + value, '', self.src)
+
+    def set_priority(self, p_priority):
+        """
+        Sets the priority of the todo. Must be a single capital letter [A-Z].
+        Priority remains unchanged when invalid priority is given.
+        """
+        if re.match('[A-Z]', p_priority):
+            self.fields['priority'] = p_priority
+            self.src = re.sub(r'^\([A-Z]\)', '(' + p_priority + ')', self.src)
+
+    def priority(self):
+        """
+        Returns the priority of this todo, or None if no priority is set.
+        """
+        return self.priority
+
+    def text(self):
+        """ Returns the todo text with tags stripped off. """
+        return self.text
+
+    def __print__(self):
+        """ A printer for the todo item. """
+        print self.src + "\n"

TodoParser.py

+"""
+This module contains the parse function which parses a single line of a
+todo.txt file.
+"""
+
+import re
+
+def parse_line(p_string):
+    """
+    Parses a single line as can be encountered in a todo.txt file.
+    First checks whether the standard elements are present, such as priority,
+    creation date, completeness check and the completion date.
+
+    Then the rest of the analyzed for any occurences of contexts, projects or
+    tags.
+
+    Returns an dictionary with the default values as shown below.
+    """
+    result = {
+        'completed': False,
+        'completionDate': None,
+        'priority': None,
+        'creationDate': None,
+        'text': "",
+        'projects': [],
+        'contexts': [],
+        'tags': []
+    }
+
+    date = r'\d{4}-\d{2}-\d{2}'
+    completed_head = re.match(
+        r'x ((?P<completionDate>' + date + ') )' +
+        '((?P<creationDate>' + date + ') )?(?P<rest>.*)',
+        p_string
+    )
+
+    normal_head = re.match(
+        r'(\((?P<priority>[A-Z])\) )?' +
+        '((?P<creationDate>' + date + ') )?(?P<rest>.*)',
+        p_string
+    )
+
+    rest = p_string
+
+    if completed_head:
+        result['completed'] = True
+        result['completionDate'] = completed_head.group('completionDate')
+        result['creationDate'] = completed_head.group('creationDate')
+        rest = completed_head.group('rest')
+    elif normal_head:
+        result['priority'] = normal_head.group('priority')
+        result['creationDate'] = normal_head.group('creationDate')
+        rest = normal_head.group('rest')
+
+    for word in rest.split():
+        project = re.match(r'\+(.*)', word)
+        if project:
+            result['projects'].append(project.group(1))
+
+        context = re.match('@(.*)', word)
+        if context:
+            result['contexts'].append(context.group(1))
+
+        tag = re.match('(?P<key>.*):(?P<value>.*)', word)
+        if tag:
+            result['tags'].append((tag.group('key'), tag.group('value')))
+            continue
+
+        result['text'] += word + ' '
+
+    # strip trailing space from resulting text
+    result['text'] = result['text'][:-1]
+
+    return result
+