Add new function: 'initial'

test/test_functions.py

@@ -132,6 +132,25 @@ def test_if_def_true_complete(self):
     def test_if_def_false_complete(self):
         self.parseEqual(u'%ifdef{trill,lol,troll}', u'troll')
 
+    # initial
+    def test_initial_use_first_character(self):
+        self.parseEqual(u'%initial{abc}', u'a')
+
+    def test_initial_german_umlaut(self):
+        self.parseEqual(u'%initial{ä}', u'a')
+
+    def test_initial_special_characters(self):
+        self.parseEqual(u'%initial{-a-}', u'a')
+
+    def test_initial_nothing(self):
+        self.parseEqual(u'%initial{}', u'_')
+
+    def test_initial_number(self):
+        self.parseEqual(u'%initial{3}', u'0')
+
+    def test_initial_lower(self):
+        self.parseEqual(u'%initial{A}', u'a')
+
     # left
     def test_left_literal(self):
         self.parseEqual(u'%left{Schubert, 3}', u'Sch')

tmep/functions.py

@@ -201,6 +201,34 @@ def tmpl_ifdefnotempty(self, field, trueval=u'', falseval=u''):
         else:
             return trueval
 
+    @staticmethod
+    def tmpl_initial(text):
+        """
+
+        * synopsis: ``%initial{text}``
+        * description: Get the first character of a text in lowercase. The \
+            text is converted to ASCII. All non word characters are erased.
+            Only letters and numbers are preserved. If the first character is
+            a number, then the result is '0'.
+
+        :param string text: Input text to build initial from.
+        :return: A single character
+        """
+        text = unidecode(text)
+        text = re.sub(r'[^a-zA-Z0-9]+', '', text)
+        text = text[0:1]
+        text = text.lower()
+        if not text:
+            return '_'
+
+        try:
+            int(text)
+            text = '0'
+        except:
+            pass
+
+        return text
+
     @staticmethod
     def tmpl_left(s, chars):
         """Get the leftmost characters of a string.