Initial attempt at adding Birth events from 1841 census

Form/UK1841.py

@@ -18,11 +18,12 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 #
 
+from gramps.gen.datehandler import displayer as date_displayer
 from gramps.gen.display.name import displayer as name_displayer
-from gramps.gen.lib import (Event, EventType, EventRef, EventRoleType,
+from gramps.gen.lib import (Date, Event, EventType, EventRef, EventRoleType,
                             Person)
 
-from actionbase import ActionBase
+from actionbase import ActionBase, represents_int
 
 #------------------------------------------------------------------------
 #
@@ -56,6 +57,44 @@ def command(db, trans, citation_handle, person_handle):
         person.get_primary_name().add_citation(citation_handle)
         db.commit_person(person, trans)
 
+class BirthEvent(ActionBase):
+    def __init__(self):
+        ActionBase.__init__(self)
+        pass
+
+    def populate_model(self, db, citation, form_event, model):
+        # if there is no date on the form, no actions can be performed
+        if form_event.get_date_object():
+            parent = model.append(None, (_("Add Birth event"), None, None))
+            for item in db.find_backlink_handles(form_event.get_handle(),
+                                                include_classes=['Person']):
+                handle = item[1]
+                person = db.get_person_from_handle(handle)
+                for event_ref in person.get_event_ref_list():
+                    if event_ref.ref == form_event.get_handle():
+                        for attr in event_ref.get_attribute_list():
+                            if (attr.get_type() == "Age"): # Form specific _attribute name
+                                age_string = attr.get_value()
+                                if age_string and represents_int(age_string):
+                                    age = int(age_string)
+                                    if age:
+                                        birth_date = form_event.get_date_object() - age
+                                        birth_date.make_vague()
+                                        # Age was rounded down to the nearest five years for those aged 15 or over
+                                        # In practice this rule was not always followed by enumerators
+                                        if age < 15:
+                                            # no adjustment required
+                                            birth_date.set_modifier(Date.MOD_ABOUT)
+                                        elif not birth_date.is_compound():
+                                            # in theory, birth_date will never be compound since 1841 census date was 1841-06-06. Let's handle it anyway.
+                                            # create a compound range spanning the possible birth years
+                                            birth_range = (birth_date - 5).get_dmy() + (False,) + birth_date.get_dmy() + (False,)
+                                            birth_date.set(Date.QUAL_NONE, Date.MOD_RANGE, birth_date.get_calendar(), birth_range, newyear=birth_date.get_new_year())
+                                        birth_date.set_quality(Date.QUAL_CALCULATED)
+
+                                        model.append(parent, (name_displayer.display(person), date_displayer.display(birth_date),
+                                                     lambda db, trans, citation_handle = citation.handle, person_handle = person.handle, birth_date_ = birth_date: ActionBase.AddEventToPerson(db, trans, person_handle, EventType.BIRTH, birth_date_, None, citation_handle, EventRoleType.PRIMARY)))
+
 class OccupationEvent(ActionBase):
     def __init__(self):
         ActionBase.__init__(self)

Form/actionbase.py

@@ -52,3 +52,13 @@ def AddEventToPerson(db, trans, person_handle, event_type, event_date_object, ev
         person = db.get_person_from_handle(person_handle)
         person.add_event_ref(event_ref)
         db.commit_person(person, trans)
+
+def represents_int(s):
+    """
+    return True iff s is convertable to an int, False otherwise
+    """
+    try:
+        int(s)
+        return True
+    except ValueError:
+        return False