Renamed Extract -> Transform

django/db/models/__init__.py

@@ -17,7 +17,7 @@ from django.db.models.fields.related import (  # NOQA
 from django.db.models.fields.proxy import OrderWrt  # NOQA
 from django.db.models.deletion import (  # NOQA
     CASCADE, PROTECT, SET, SET_NULL, SET_DEFAULT, DO_NOTHING, ProtectedError)
-from django.db.models.lookups import Lookup, Extract  # NOQA
+from django.db.models.lookups import Lookup, Transform  # NOQA
 from django.db.models import signals  # NOQA
 
 

django/db/models/lookups.py

@@ -39,7 +39,7 @@ class RegisterLookupMixin(object):
         del cls.class_lookups[lookup.lookup_name]
 
 
-class Extract(RegisterLookupMixin):
+class Transform(RegisterLookupMixin):
     def __init__(self, lhs, lookups):
         self.lhs = lhs
         self.init_lookups = lookups[:]

django/db/models/sql/query.py

@@ -19,7 +19,7 @@ from django.db.models.constants import LOOKUP_SEP
 from django.db.models.aggregates import refs_aggregate
 from django.db.models.expressions import ExpressionNode
 from django.db.models.fields import FieldDoesNotExist
-from django.db.models.lookups import Extract
+from django.db.models.lookups import Transform
 from django.db.models.query_utils import Q
 from django.db.models.related import PathInfo
 from django.db.models.sql import aggregates as base_aggregates_module
@@ -1092,7 +1092,7 @@ class Query(object):
             if next:
                 if len(lookups) == 1:
                     # This was the last lookup, so return value lookup.
-                    if issubclass(next, Extract):
+                    if issubclass(next, Transform):
                         lookups.append('exact')
                         lhs = next(lhs, lookups)
                     else:

docs/ref/models/custom_lookups.txt

@@ -99,9 +99,9 @@ or where it did not exceede a certain amount
 We will start by writing a ``AbsoluteValue`` transformer. This will use the SQL
 function ``ABS()`` to transform the value before comparison::
 
-  from django.db.models import Extract
+  from django.db.models import Transform
 
-  class AbsoluteValue(Extract):
+  class AbsoluteValue(Transform):
       lookup_name = 'abs'
 
       def as_sql(self, qn, connection):
@@ -118,19 +118,19 @@ We can now run the queris we had before.
 
     SELECT ... WHERE ABS("experiments"."change") = 27
 
-By using ``Extract`` instead of ``Lookup`` it means we are able to chain
+By using ``Transform`` instead of ``Lookup`` it means we are able to chain
 further lookups afterwards. So
 ``Experiment.objects.filter(change__abs__lt=27)`` will generate the following
 SQL::
 
     SELECT ... WHERE ABS("experiments"."change") < 27
 
-Subclasses of ``Extract`` usually only operate on the left-hand side of the
+Subclasses of ``Transform`` usually only operate on the left-hand side of the
 expression. Further lookups will work on the transformed value. Note that in
 this case where there is no other lookup specified, Django interprets
 ``change__abs=27`` as ``change__abs__exact=27``.
 
-When looking for which lookups are allowable after the ``Extract`` has been
+When looking for which lookups are allowable after the ``Transform`` has been
 applied, Django uses the ``output_type`` attribute. We didn't need to specify
 this here as it didn't change, but supposing we were applying ``AbsoluteValue``
 to some field which represents a more complex type (for example a point
@@ -222,7 +222,7 @@ The Query Expression API
 ~~~~~~~~~~~~~~~~~~~~~~~~
 
 A lookup can assume that the lhs responds to the query expression API.
-Currently direct field references, aggregates and ``Extract`` instances respond
+Currently direct field references, aggregates and ``Transform`` instances respond
 to this API.
 
 .. method:: as_sql(qn, connection)
@@ -269,7 +269,7 @@ Lookup reference
 
     The ``lhs`` (left-hand side) of a lookup tells us what we are comparing the
     rhs to. It is an object which implements the query expression API. This is
-    likely to be a field, an aggregate or a subclass of ``Extract``.
+    likely to be a field, an aggregate or a subclass of ``Transform``.
 
 .. attribute:: rhs