def __add__(self, right):
"""
>>> plb1 = plumb(1)
>>> plb1 + plumb(1) is plb1
True
>>> plb1 + Instruction(1)
Traceback (most recent call last):
...
PlumbingCollision:
<plumb 'None' of None payload=1>
with:
<Instruction 'None' of None payload=1>
>>> plumb(lambda x: None) + plumb(property(lambda x: None))
Traceback (most recent call last):
...
PlumbingCollision:
<plumb 'None' of None payload=<function <lambda> at 0x...>>
with:
<plumb 'None' of None payload=<property object at 0x...>>
"""
if self == right:
return self
if not isinstance(right, plumb):
raise PlumbingCollision(self, right)
if not self.ok(self.payload, right.payload):
raise PlumbingCollision(self, right)
return plumb(self.plumb(plumbingfor, self.payload, right.payload),
name=self.name)
def __add__(self, right):
if self == right:
return self
if not isinstance(right, _implements):
raise PlumbingCollision(self, right)
ifaces = self.payload + right.payload
return _implements(ifaces)
def __call__(self, cls):
# Check for a method on the plumbing class itself.
_next = getattr(cls, self.name)
if not self.ok(self.payload, _next):
raise PlumbingCollision(self, cls)
entrance = self.plumb(entrancefor, self.payload, _next)
setattr(cls, self.name, entrance)
def __add__(self, right):
"""
First default wins from left to right::
>>> def1 = default(1)
>>> def1 + def1 is def1
True
>>> def2 = default(2)
>>> def1 + def2 is def1
True
>>> def2 + def1 is def2
True
Override wins over default::
>>> ext3 = override(3)
>>> def1 + ext3 is ext3
True
Finalize wins over default::
>>> fin4 = finalize(4)
>>> def1 + fin4 is fin4
True
Adding with something else than default/override, raises
``PlumbingCollision``::
>>> def1 + Instruction('foo')
Traceback (most recent call last):
...
PlumbingCollision:
<default 'None' of None payload=1>
with:
<Instruction 'None' of None payload='foo'>
"""
if self == right:
return self
if isinstance(right, default):
return self
if isinstance(right, override):
return right
if isinstance(right, finalize):
return right
raise PlumbingCollision(self, right)
def __add__(self, right):
"""
First override wins against following equal overrides and arbitrary
defaults::
>>> fin1 = finalize(1)
>>> fin1 + fin1 is fin1
True
>>> fin1 + finalize(1) is fin1
True
>>> fin1 + default(2) is fin1
True
>>> fin1 + override(2) is fin1
True
Two unequal finalize collide::
>>> fin1 + finalize(2)
Traceback (most recent call last):
...
PlumbingCollision:
<finalize 'None' of None payload=1>
with:
<finalize 'None' of None payload=2>
Everything except default/override collides::
>>> fin1 + Instruction(1)
Traceback (most recent call last):
...
PlumbingCollision:
<finalize 'None' of None payload=1>
with:
<Instruction 'None' of None payload=1>
"""
if self == right:
return self
if isinstance(right, default):
return self
if isinstance(right, override):
return self
raise PlumbingCollision(self, right)
def __call__(self, dct, bases):
if self.name in dct:
raise PlumbingCollision('Plumbing class', self)
dct[self.name] = self.payload
def __call__(self, dct, bases):
if dct.has_key(self.name):
raise PlumbingCollision('Plumbing class', self)
dct[self.name] = self.payload