- add hybrid extension

- mapper begins to lose awareness of SynonynmProperty, ComparableProperty

1 files changed, 111 insertions, 0 deletions

diff --git a/lib/sqlalchemy/ext/hybrid.py b/lib/sqlalchemy/ext/hybrid.py
new file mode 100644
index 000000000..2432ec9d7
--- /dev/null
+++ b/lib/sqlalchemy/ext/hybrid.py
@@ -0,0 +1,111 @@
+"""Define attributes on ORM-mapped classes that have 'hybrid' behavior.
+
+'hybrid' means the attribute has distinct behaviors defined at the
+class level and at the instance level.
+
+Consider a table `interval` as below::
+
+    from sqlalchemy import MetaData, Table, Column, Integer
+    from sqlalchemy.orm import mapper, create_session
+    
+    engine = create_engine('sqlite://')
+    metadata = MetaData()
+
+    interval_table = Table('interval', metadata,
+        Column('id', Integer, primary_key=True),
+        Column('start', Integer, nullable=False),
+        Column('end', Integer, nullable=False))
+    metadata.create_all(engine)
+    
+We can define higher level functions on mapped classes that produce SQL
+expressions at the class level, and Python expression evaluation at the
+instance level.  Below, each function decorated with :func:`hybrid.method`
+or :func:`hybrid.property` may receive ``self`` as an instance of the class,
+or as the class itself::
+    
+    # A base class for intervals
+
+    from sqlalchemy.orm import hybrid
+    
+    class Interval(object):
+        def __init__(self, start, end):
+            self.start = start
+            self.end = end
+        
+        @hybrid.property
+        def length(self):
+            return self.end - self.start
+
+        @hybrid.method
+        def contains(self,point):
+            return (self.start <= point) & (point < self.end)
+    
+        @hybrid.method
+        def intersects(self, other):
+            return (self.start < other.end) & (self.end > other.start)
+
+    mapper(Interval1, interval_table1)
+
+    session = sessionmaker(engine)()
+
+    session.add_all(
+        [Interval1(1,4), Interval1(3,15), Interval1(11,16)]
+    )
+    intervals = 
+
+    for interval in intervals:
+        session.add(interval)
+        session.add(Interval2(interval.start, interval.length))
+
+    session.commit()
+
+    ### TODO ADD EXAMPLES HERE AND STUFF THIS ISN'T FINISHED ###
+    
+"""
+
+class method(object):
+    def __init__(self, func, expr=None):
+        self.func = func
+        self.expr = expr or fund
+        
+    def __get__(self, instance, owner):
+        if instance is None:
+            return new.instancemethod(self.expr, owner, owner.__class__)
+        else:
+            return new.instancemethod(self.func, instance, owner)
+
+    def expression(self, expr):
+        self.expr = expr
+        return self
+
+class property(object):
+    def __init__(self, fget, fset=None, fdel=None, expr=None):
+        self.fget = fget
+        self.fset = fset
+        self.fdel = fdel
+        self.expr = expr or fget
+        
+    def __get__(self, instance, owner):
+        if instance is None:
+            return self.expr(owner)
+        else:
+            return self.fget(instance)
+            
+    def __set__(self, instance, value):
+        self.fset(instance, value)
+        
+    def __delete__(self, instance):
+        self.fdel(instance)
+    
+    def setter(self, fset):
+        self.fset = fset
+        return self
+
+    def deleter(self, fdel):
+        self.fdel = fdel
+        return self
+    
+    def expression(self, expr):
+        self.expr = expr
+        return self
+