from ... import _doc_wrapper
from .. import matchable
from . import common
[docs]@_doc_wrapper.DocWrapper.wrap_class
class Property(common.Descriptor):
"""Decorator with value-based dispatch. Acts as a property."""
fset = None
fdel = None
protected = False
def __new__(cls, func=None, fset=None, fdel=None, doc=None, *args, **kwargs):
del fset, fdel, doc
return super().__new__(cls, func, *args, **kwargs)
def __init__(self, func=None, fset=None, fdel=None, doc=None, *args, **kwargs):
del func
super().__init__(*args, **kwargs)
self.fset = fset
self.fdel = fdel
if doc is not None:
self.__doc__ = doc
self.get_matchers = []
self.set_matchers = []
self.delete_matchers = []
self.protected = True
def __setattr__(self, name, value):
if self.protected and name != "__doc__":
raise AttributeError
super().__setattr__(name, value)
def __delattr__(self, name):
if self.protected and name != "__doc__":
raise AttributeError
super().__delattr__(name)
[docs] def getter(self, getter):
"""Return a copy of self with the getter replaced."""
new = Property(getter, self.fset, self.fdel, self.__doc__)
new.get_matchers.extend(self.get_matchers)
new.set_matchers.extend(self.set_matchers)
new.delete_matchers.extend(self.delete_matchers)
return new
[docs] def setter(self, setter):
"""Return a copy of self with the setter replaced."""
new = Property(self.__wrapped__, setter, self.fdel, self.__doc__)
new.get_matchers.extend(self.get_matchers)
new.set_matchers.extend(self.set_matchers)
new.delete_matchers.extend(self.delete_matchers)
return new
[docs] def deleter(self, deleter):
"""Return a copy of self with the deleter replaced."""
new = Property(self.__wrapped__, self.fset, deleter, self.__doc__)
new.get_matchers.extend(self.get_matchers)
new.set_matchers.extend(self.set_matchers)
new.delete_matchers.extend(self.delete_matchers)
return new
def __get__(self, instance, owner):
if instance is None:
return self
matchable_ = matchable.Matchable(instance)
for (structure, func) in self.get_matchers:
if matchable_(structure):
return func(**matchable_.matches)
if self.__wrapped__ is None:
raise ValueError(self)
return self.__wrapped__(instance)
def __set__(self, instance, value):
matchable_ = matchable.Matchable((instance, value))
for (structure, func) in self.set_matchers:
if matchable_(structure):
func(**matchable_.matches)
return
if self.fset is None:
raise ValueError((instance, value))
self.fset(instance, value)
def __delete__(self, instance):
matchable_ = matchable.Matchable(instance)
for (structure, func) in self.delete_matchers:
if matchable_(structure):
func(**matchable_.matches)
return
if self.fdel is None:
raise ValueError(instance)
self.fdel(instance)
[docs] def get_when(self, instance):
"""Add a binding to the getter."""
return common.decorate(self.get_matchers, instance)
[docs] def set_when(self, instance, value):
"""Add a binding to the setter."""
return common.decorate(self.set_matchers, (instance, value))
[docs] def delete_when(self, instance):
"""Add a binding to the deleter."""
return common.decorate(self.delete_matchers, instance)
