Changeset 4506

Timestamp:

02/14/07 17:44:46 (2 years ago)

Author:

adrian

Message:

Implemented subclassing Forms in newforms

Files:

• django/trunk/django/newforms/forms.py (modified) (1 diff)
• django/trunk/docs/newforms.txt (modified) (1 diff)
• django/trunk/tests/regressiontests/forms/tests.py (modified) (1 diff)

django/trunk/django/newforms/forms.py

@@ -32 +32 @@
-
-class DeclarativeFieldsMetaclass(type):
-
+
+
+
+
-    def __new__(cls, name, bases, attrs):
-        fields = [(field_name, attrs.pop(field_name)) for field_name, obj in attrs.items() if isinstance(obj, Field)]
-        fields.sort(lambda x, y: cmp(x[1].creation_counter, y[1].creation_counter))
+
+        # If this class is subclassing another Form, add that Form's fields.
+        # Note that we loop over the bases in *reverse*. This is necessary in
+        # order to preserve the correct order of fields.
+        for base in bases[::-1]:
+            if hasattr(base, 'base_fields'):
+                fields = base.base_fields.items() + fields
+
-        attrs['base_fields'] = SortedDictFromList(fields)
-        return type.__new__(cls, name, bases, attrs)

django/trunk/docs/newforms.txt

@@ -572 +572 @@
-    ''
-
+Subclassing forms
+-----------------
+
+If you subclass a custom ``Form`` class, the resulting ``Form`` class will
+include all fields of the parent class(es), followed by the fields you define
+in the subclass.
+
+In this example, ``ContactFormWithPriority`` contains all the fields from
+``ContactForm``, plus an additional field, ``priority``. The ``ContactForm``
+fields are ordered first::
+
+    >>> class ContactFormWithPriority(ContactForm):
+    ...     priority = forms.CharField()
+    >>> f = ContactFormWithPriority(auto_id=False)
+    >>> print f.as_ul()
+    <li>Subject: <input type="text" name="subject" maxlength="100" /></li>
+    <li>Message: <input type="text" name="message" /></li>
+    <li>Sender: <input type="text" name="sender" /></li>
+    <li>Cc myself: <input type="checkbox" name="cc_myself" /></li>
+    <li>Priority: <input type="text" name="priority" /></li>
+
+It's possible to subclass multiple forms, treating forms as "mix-ins." In this
+example, ``BeatleForm`` subclasses both ``PersonForm`` and ``InstrumentForm``
+(in that order), and its field list includes the fields from the parent
+classes::
+
+    >>> class PersonForm(Form):
+    ...     first_name = CharField()
+    ...     last_name = CharField()
+    >>> class InstrumentForm(Form):
+    ...     instrument = CharField()
+    >>> class BeatleForm(PersonForm, InstrumentForm):
+    ...     haircut_type = CharField()
+    >>> b = Beatle(auto_id=False)
+    >>> print b.as_ul()
+    <li>First name: <input type="text" name="first_name" /></li>
+    <li>Last name: <input type="text" name="last_name" /></li>
+    <li>Instrument: <input type="text" name="instrument" /></li>
+    <li>Haircut type: <input type="text" name="haircut_type" /></li>
+
-Fields
-======

django/trunk/tests/regressiontests/forms/tests.py

@@ -2683 +2683 @@
-<li>Password: <input type="password" name="password" /><input type="hidden" name="next" value="/" /></li>
-
+# Subclassing forms ###########################################################
+
+You can subclass a Form to add fields. The resulting form subclass will have
+all of the fields of the parent Form, plus whichever fields you define in the
+subclass.
+>>> class Person(Form):
+...     first_name = CharField()
+...     last_name = CharField()
+...     birthday = DateField()
+>>> class Musician(Person):
+...     instrument = CharField()
+>>> p = Person(auto_id=False)
+>>> print p.as_ul()
+<li>First name: <input type="text" name="first_name" /></li>
+<li>Last name: <input type="text" name="last_name" /></li>
+<li>Birthday: <input type="text" name="birthday" /></li>
+>>> m = Musician(auto_id=False)
+>>> print m.as_ul()
+<li>First name: <input type="text" name="first_name" /></li>
+<li>Last name: <input type="text" name="last_name" /></li>
+<li>Birthday: <input type="text" name="birthday" /></li>
+<li>Instrument: <input type="text" name="instrument" /></li>
+
+Yes, you can subclass multiple forms. The fields are added in the order in
+which the parent classes are listed.
+>>> class Person(Form):
+...     first_name = CharField()
+...     last_name = CharField()
+...     birthday = DateField()
+>>> class Instrument(Form):
+...     instrument = CharField()
+>>> class Beatle(Person, Instrument):
+...     haircut_type = CharField()
+>>> b = Beatle(auto_id=False)
+>>> print b.as_ul()
+<li>First name: <input type="text" name="first_name" /></li>
+<li>Last name: <input type="text" name="last_name" /></li>
+<li>Birthday: <input type="text" name="birthday" /></li>
+<li>Instrument: <input type="text" name="instrument" /></li>
+<li>Haircut type: <input type="text" name="haircut_type" /></li>
+
-# Forms with prefixes #########################################################
-