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# encoding: utf-8
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"""
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A lightweight Traits like module.
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This is designed to provide a lightweight, simple, pure Python version of
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many of the capabilities of enthought.traits. This includes:
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* Validation
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* Type specification with defaults
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* Static and dynamic notification
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* Basic predefined types
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* An API that is similar to enthought.traits
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We don't support:
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* Delegation
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* Automatic GUI generation
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* A full set of trait types. Most importantly, we don't provide container
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traits (list, dict, tuple) that can trigger notifications if their
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contents change.
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* API compatibility with enthought.traits
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There are also some important difference in our design:
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* enthought.traits does not validate default values. We do.
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We choose to create this module because we need these capabilities, but
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we need them to be pure Python so they work in all Python implementations,
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including Jython and IronPython.
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Inheritance diagram:
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.. inheritance-diagram:: IPython.utils.traitlets
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:parts: 3
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"""
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# Copyright (c) IPython Development Team.
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# Distributed under the terms of the Modified BSD License.
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#
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# Adapted from enthought.traits, Copyright (c) Enthought, Inc.,
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# also under the terms of the Modified BSD License.
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import contextlib
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import inspect
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import re
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import sys
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import types
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from types import FunctionType
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try:
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from types import ClassType, InstanceType
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ClassTypes = (ClassType, type)
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except:
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ClassTypes = (type,)
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from .importstring import import_item
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from IPython.utils import py3compat
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from IPython.utils import eventful
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from IPython.utils.py3compat import iteritems, string_types
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from IPython.testing.skipdoctest import skip_doctest
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SequenceTypes = (list, tuple, set, frozenset)
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#-----------------------------------------------------------------------------
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# Basic classes
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#-----------------------------------------------------------------------------
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class NoDefaultSpecified ( object ): pass
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NoDefaultSpecified = NoDefaultSpecified()
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class Undefined ( object ): pass
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Undefined = Undefined()
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class TraitError(Exception):
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pass
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#-----------------------------------------------------------------------------
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# Utilities
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#-----------------------------------------------------------------------------
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def class_of ( object ):
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""" Returns a string containing the class name of an object with the
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correct indefinite article ('a' or 'an') preceding it (e.g., 'an Image',
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'a PlotValue').
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"""
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if isinstance( object, py3compat.string_types ):
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return add_article( object )
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return add_article( object.__class__.__name__ )
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def add_article ( name ):
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""" Returns a string containing the correct indefinite article ('a' or 'an')
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prefixed to the specified string.
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"""
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if name[:1].lower() in 'aeiou':
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return 'an ' + name
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return 'a ' + name
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def repr_type(obj):
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""" Return a string representation of a value and its type for readable
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error messages.
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"""
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the_type = type(obj)
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if (not py3compat.PY3) and the_type is InstanceType:
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# Old-style class.
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the_type = obj.__class__
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msg = '%r %r' % (obj, the_type)
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return msg
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def is_trait(t):
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""" Returns whether the given value is an instance or subclass of TraitType.
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"""
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return (isinstance(t, TraitType) or
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(isinstance(t, type) and issubclass(t, TraitType)))
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def parse_notifier_name(name):
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"""Convert the name argument to a list of names.
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Examples
|
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--------
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>>> parse_notifier_name('a')
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['a']
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>>> parse_notifier_name(['a','b'])
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['a', 'b']
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>>> parse_notifier_name(None)
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['anytrait']
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"""
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if isinstance(name, string_types):
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return [name]
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elif name is None:
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return ['anytrait']
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elif isinstance(name, (list, tuple)):
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for n in name:
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assert isinstance(n, string_types), "names must be strings"
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return name
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class _SimpleTest:
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def __init__ ( self, value ): self.value = value
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def __call__ ( self, test ):
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return test == self.value
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def __repr__(self):
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return "<SimpleTest(%r)" % self.value
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def __str__(self):
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return self.__repr__()
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def getmembers(object, predicate=None):
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"""A safe version of inspect.getmembers that handles missing attributes.
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This is useful when there are descriptor based attributes that for
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some reason raise AttributeError even though they exist. This happens
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in zope.inteface with the __provides__ attribute.
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"""
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results = []
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for key in dir(object):
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try:
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value = getattr(object, key)
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except AttributeError:
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pass
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else:
|
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if not predicate or predicate(value):
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results.append((key, value))
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results.sort()
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return results
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|
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@skip_doctest
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class link(object):
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"""Link traits from different objects together so they remain in sync.
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Parameters
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----------
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obj : pairs of objects/attributes
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|
Examples
|
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--------
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>>> c = link((obj1, 'value'), (obj2, 'value'), (obj3, 'value'))
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>>> obj1.value = 5 # updates other objects as well
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"""
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|
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updating = False
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def __init__(self, *args):
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if len(args) < 2:
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raise TypeError('At least two traitlets must be provided.')
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|
|
self.objects = {}
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initial = getattr(args[0][0], args[0][1])
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for obj,attr in args:
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if getattr(obj, attr) != initial:
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|
setattr(obj, attr, initial)
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|
|
callback = self._make_closure(obj,attr)
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|
obj.on_trait_change(callback, attr)
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|
self.objects[(obj,attr)] = callback
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|
|
|
@contextlib.contextmanager
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def _busy_updating(self):
|
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|
self.updating = True
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try:
|
|
|
yield
|
|
|
finally:
|
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|
self.updating = False
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|
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|
|
|
def _make_closure(self, sending_obj, sending_attr):
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def update(name, old, new):
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self._update(sending_obj, sending_attr, new)
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return update
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def _update(self, sending_obj, sending_attr, new):
|
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|
if self.updating:
|
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|
return
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|
|
with self._busy_updating():
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|
for obj,attr in self.objects.keys():
|
|
|
if obj is not sending_obj or attr != sending_attr:
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setattr(obj, attr, new)
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|
|
|
def unlink(self):
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for key, callback in self.objects.items():
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(obj,attr) = key
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obj.on_trait_change(callback, attr, remove=True)
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|
@skip_doctest
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class directional_link(object):
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"""Link the trait of a source object with traits of target objects.
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|
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|
Parameters
|
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----------
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|
|
source : pair of object, name
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|
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targets : pairs of objects/attributes
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|
|
|
Examples
|
|
|
--------
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|
|
|
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|
>>> c = directional_link((src, 'value'), (tgt1, 'value'), (tgt2, 'value'))
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|
|
>>> src.value = 5 # updates target objects
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|
>>> tgt1.value = 6 # does not update other objects
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|
|
"""
|
|
|
updating = False
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|
|
|
def __init__(self, source, *targets):
|
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|
self.source = source
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|
self.targets = targets
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|
# Update current value
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|
src_attr_value = getattr(source[0], source[1])
|
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|
for obj, attr in targets:
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|
if getattr(obj, attr) != src_attr_value:
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|
setattr(obj, attr, src_attr_value)
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|
|
|
# Wire
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self.source[0].on_trait_change(self._update, self.source[1])
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|
|
|
@contextlib.contextmanager
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|
|
def _busy_updating(self):
|
|
|
self.updating = True
|
|
|
try:
|
|
|
yield
|
|
|
finally:
|
|
|
self.updating = False
|
|
|
|
|
|
def _update(self, name, old, new):
|
|
|
if self.updating:
|
|
|
return
|
|
|
with self._busy_updating():
|
|
|
for obj, attr in self.targets:
|
|
|
setattr(obj, attr, new)
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|
|
|
|
|
def unlink(self):
|
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|
self.source[0].on_trait_change(self._update, self.source[1], remove=True)
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|
|
self.source = None
|
|
|
self.targets = []
|
|
|
|
|
|
def dlink(source, *targets):
|
|
|
"""Shorter helper function returning a directional_link object"""
|
|
|
return directional_link(source, *targets)
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Base TraitType for all traits
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
|
|
|
class TraitType(object):
|
|
|
"""A base class for all trait descriptors.
|
|
|
|
|
|
Notes
|
|
|
-----
|
|
|
Our implementation of traits is based on Python's descriptor
|
|
|
prototol. This class is the base class for all such descriptors. The
|
|
|
only magic we use is a custom metaclass for the main :class:`HasTraits`
|
|
|
class that does the following:
|
|
|
|
|
|
1. Sets the :attr:`name` attribute of every :class:`TraitType`
|
|
|
instance in the class dict to the name of the attribute.
|
|
|
2. Sets the :attr:`this_class` attribute of every :class:`TraitType`
|
|
|
instance in the class dict to the *class* that declared the trait.
|
|
|
This is used by the :class:`This` trait to allow subclasses to
|
|
|
accept superclasses for :class:`This` values.
|
|
|
"""
|
|
|
|
|
|
|
|
|
metadata = {}
|
|
|
default_value = Undefined
|
|
|
allow_none = False
|
|
|
info_text = 'any value'
|
|
|
|
|
|
def __init__(self, default_value=NoDefaultSpecified, allow_none=None, **metadata):
|
|
|
"""Create a TraitType.
|
|
|
"""
|
|
|
if default_value is not NoDefaultSpecified:
|
|
|
self.default_value = default_value
|
|
|
if allow_none is not None:
|
|
|
self.allow_none = allow_none
|
|
|
|
|
|
if len(metadata) > 0:
|
|
|
if len(self.metadata) > 0:
|
|
|
self._metadata = self.metadata.copy()
|
|
|
self._metadata.update(metadata)
|
|
|
else:
|
|
|
self._metadata = metadata
|
|
|
else:
|
|
|
self._metadata = self.metadata
|
|
|
|
|
|
self.init()
|
|
|
|
|
|
def init(self):
|
|
|
pass
|
|
|
|
|
|
def get_default_value(self):
|
|
|
"""Create a new instance of the default value."""
|
|
|
return self.default_value
|
|
|
|
|
|
def instance_init(self, obj):
|
|
|
"""This is called by :meth:`HasTraits.__new__` to finish init'ing.
|
|
|
|
|
|
Some stages of initialization must be delayed until the parent
|
|
|
:class:`HasTraits` instance has been created. This method is
|
|
|
called in :meth:`HasTraits.__new__` after the instance has been
|
|
|
created.
|
|
|
|
|
|
This method trigger the creation and validation of default values
|
|
|
and also things like the resolution of str given class names in
|
|
|
:class:`Type` and :class`Instance`.
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
obj : :class:`HasTraits` instance
|
|
|
The parent :class:`HasTraits` instance that has just been
|
|
|
created.
|
|
|
"""
|
|
|
self.set_default_value(obj)
|
|
|
|
|
|
def set_default_value(self, obj):
|
|
|
"""Set the default value on a per instance basis.
|
|
|
|
|
|
This method is called by :meth:`instance_init` to create and
|
|
|
validate the default value. The creation and validation of
|
|
|
default values must be delayed until the parent :class:`HasTraits`
|
|
|
class has been instantiated.
|
|
|
"""
|
|
|
# Check for a deferred initializer defined in the same class as the
|
|
|
# trait declaration or above.
|
|
|
mro = type(obj).mro()
|
|
|
meth_name = '_%s_default' % self.name
|
|
|
for cls in mro[:mro.index(self.this_class)+1]:
|
|
|
if meth_name in cls.__dict__:
|
|
|
break
|
|
|
else:
|
|
|
# We didn't find one. Do static initialization.
|
|
|
dv = self.get_default_value()
|
|
|
newdv = self._validate(obj, dv)
|
|
|
obj._trait_values[self.name] = newdv
|
|
|
return
|
|
|
# Complete the dynamic initialization.
|
|
|
obj._trait_dyn_inits[self.name] = meth_name
|
|
|
|
|
|
def __get__(self, obj, cls=None):
|
|
|
"""Get the value of the trait by self.name for the instance.
|
|
|
|
|
|
Default values are instantiated when :meth:`HasTraits.__new__`
|
|
|
is called. Thus by the time this method gets called either the
|
|
|
default value or a user defined value (they called :meth:`__set__`)
|
|
|
is in the :class:`HasTraits` instance.
|
|
|
"""
|
|
|
if obj is None:
|
|
|
return self
|
|
|
else:
|
|
|
try:
|
|
|
value = obj._trait_values[self.name]
|
|
|
except KeyError:
|
|
|
# Check for a dynamic initializer.
|
|
|
if self.name in obj._trait_dyn_inits:
|
|
|
method = getattr(obj, obj._trait_dyn_inits[self.name])
|
|
|
value = method()
|
|
|
# FIXME: Do we really validate here?
|
|
|
value = self._validate(obj, value)
|
|
|
obj._trait_values[self.name] = value
|
|
|
return value
|
|
|
else:
|
|
|
raise TraitError('Unexpected error in TraitType: '
|
|
|
'both default value and dynamic initializer are '
|
|
|
'absent.')
|
|
|
except Exception:
|
|
|
# HasTraits should call set_default_value to populate
|
|
|
# this. So this should never be reached.
|
|
|
raise TraitError('Unexpected error in TraitType: '
|
|
|
'default value not set properly')
|
|
|
else:
|
|
|
return value
|
|
|
|
|
|
def __set__(self, obj, value):
|
|
|
new_value = self._validate(obj, value)
|
|
|
old_value = self.__get__(obj)
|
|
|
obj._trait_values[self.name] = new_value
|
|
|
try:
|
|
|
silent = bool(old_value == new_value)
|
|
|
except:
|
|
|
# if there is an error in comparing, default to notify
|
|
|
silent = False
|
|
|
if silent is not True:
|
|
|
# we explicitly compare silent to True just in case the equality
|
|
|
# comparison above returns something other than True/False
|
|
|
obj._notify_trait(self.name, old_value, new_value)
|
|
|
|
|
|
def _validate(self, obj, value):
|
|
|
if value is None and self.allow_none:
|
|
|
return value
|
|
|
if hasattr(self, 'validate'):
|
|
|
return self.validate(obj, value)
|
|
|
elif hasattr(self, 'is_valid_for'):
|
|
|
valid = self.is_valid_for(value)
|
|
|
if valid:
|
|
|
return value
|
|
|
else:
|
|
|
raise TraitError('invalid value for type: %r' % value)
|
|
|
elif hasattr(self, 'value_for'):
|
|
|
return self.value_for(value)
|
|
|
else:
|
|
|
return value
|
|
|
|
|
|
def info(self):
|
|
|
return self.info_text
|
|
|
|
|
|
def error(self, obj, value):
|
|
|
if obj is not None:
|
|
|
e = "The '%s' trait of %s instance must be %s, but a value of %s was specified." \
|
|
|
% (self.name, class_of(obj),
|
|
|
self.info(), repr_type(value))
|
|
|
else:
|
|
|
e = "The '%s' trait must be %s, but a value of %r was specified." \
|
|
|
% (self.name, self.info(), repr_type(value))
|
|
|
raise TraitError(e)
|
|
|
|
|
|
def get_metadata(self, key, default=None):
|
|
|
return getattr(self, '_metadata', {}).get(key, default)
|
|
|
|
|
|
def set_metadata(self, key, value):
|
|
|
getattr(self, '_metadata', {})[key] = value
|
|
|
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# The HasTraits implementation
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
|
|
|
class MetaHasTraits(type):
|
|
|
"""A metaclass for HasTraits.
|
|
|
|
|
|
This metaclass makes sure that any TraitType class attributes are
|
|
|
instantiated and sets their name attribute.
|
|
|
"""
|
|
|
|
|
|
def __new__(mcls, name, bases, classdict):
|
|
|
"""Create the HasTraits class.
|
|
|
|
|
|
This instantiates all TraitTypes in the class dict and sets their
|
|
|
:attr:`name` attribute.
|
|
|
"""
|
|
|
# print "MetaHasTraitlets (mcls, name): ", mcls, name
|
|
|
# print "MetaHasTraitlets (bases): ", bases
|
|
|
# print "MetaHasTraitlets (classdict): ", classdict
|
|
|
for k,v in iteritems(classdict):
|
|
|
if isinstance(v, TraitType):
|
|
|
v.name = k
|
|
|
elif inspect.isclass(v):
|
|
|
if issubclass(v, TraitType):
|
|
|
vinst = v()
|
|
|
vinst.name = k
|
|
|
classdict[k] = vinst
|
|
|
return super(MetaHasTraits, mcls).__new__(mcls, name, bases, classdict)
|
|
|
|
|
|
def __init__(cls, name, bases, classdict):
|
|
|
"""Finish initializing the HasTraits class.
|
|
|
|
|
|
This sets the :attr:`this_class` attribute of each TraitType in the
|
|
|
class dict to the newly created class ``cls``.
|
|
|
"""
|
|
|
for k, v in iteritems(classdict):
|
|
|
if isinstance(v, TraitType):
|
|
|
v.this_class = cls
|
|
|
super(MetaHasTraits, cls).__init__(name, bases, classdict)
|
|
|
|
|
|
class HasTraits(py3compat.with_metaclass(MetaHasTraits, object)):
|
|
|
|
|
|
def __new__(cls, *args, **kw):
|
|
|
# This is needed because object.__new__ only accepts
|
|
|
# the cls argument.
|
|
|
new_meth = super(HasTraits, cls).__new__
|
|
|
if new_meth is object.__new__:
|
|
|
inst = new_meth(cls)
|
|
|
else:
|
|
|
inst = new_meth(cls, **kw)
|
|
|
inst._trait_values = {}
|
|
|
inst._trait_notifiers = {}
|
|
|
inst._trait_dyn_inits = {}
|
|
|
# Here we tell all the TraitType instances to set their default
|
|
|
# values on the instance.
|
|
|
for key in dir(cls):
|
|
|
# Some descriptors raise AttributeError like zope.interface's
|
|
|
# __provides__ attributes even though they exist. This causes
|
|
|
# AttributeErrors even though they are listed in dir(cls).
|
|
|
try:
|
|
|
value = getattr(cls, key)
|
|
|
except AttributeError:
|
|
|
pass
|
|
|
else:
|
|
|
if isinstance(value, TraitType):
|
|
|
value.instance_init(inst)
|
|
|
|
|
|
return inst
|
|
|
|
|
|
def __init__(self, *args, **kw):
|
|
|
# Allow trait values to be set using keyword arguments.
|
|
|
# We need to use setattr for this to trigger validation and
|
|
|
# notifications.
|
|
|
for key, value in iteritems(kw):
|
|
|
setattr(self, key, value)
|
|
|
|
|
|
def _notify_trait(self, name, old_value, new_value):
|
|
|
|
|
|
# First dynamic ones
|
|
|
callables = []
|
|
|
callables.extend(self._trait_notifiers.get(name,[]))
|
|
|
callables.extend(self._trait_notifiers.get('anytrait',[]))
|
|
|
|
|
|
# Now static ones
|
|
|
try:
|
|
|
cb = getattr(self, '_%s_changed' % name)
|
|
|
except:
|
|
|
pass
|
|
|
else:
|
|
|
callables.append(cb)
|
|
|
|
|
|
# Call them all now
|
|
|
for c in callables:
|
|
|
# Traits catches and logs errors here. I allow them to raise
|
|
|
if callable(c):
|
|
|
argspec = inspect.getargspec(c)
|
|
|
nargs = len(argspec[0])
|
|
|
# Bound methods have an additional 'self' argument
|
|
|
# I don't know how to treat unbound methods, but they
|
|
|
# can't really be used for callbacks.
|
|
|
if isinstance(c, types.MethodType):
|
|
|
offset = -1
|
|
|
else:
|
|
|
offset = 0
|
|
|
if nargs + offset == 0:
|
|
|
c()
|
|
|
elif nargs + offset == 1:
|
|
|
c(name)
|
|
|
elif nargs + offset == 2:
|
|
|
c(name, new_value)
|
|
|
elif nargs + offset == 3:
|
|
|
c(name, old_value, new_value)
|
|
|
else:
|
|
|
raise TraitError('a trait changed callback '
|
|
|
'must have 0-3 arguments.')
|
|
|
else:
|
|
|
raise TraitError('a trait changed callback '
|
|
|
'must be callable.')
|
|
|
|
|
|
|
|
|
def _add_notifiers(self, handler, name):
|
|
|
if name not in self._trait_notifiers:
|
|
|
nlist = []
|
|
|
self._trait_notifiers[name] = nlist
|
|
|
else:
|
|
|
nlist = self._trait_notifiers[name]
|
|
|
if handler not in nlist:
|
|
|
nlist.append(handler)
|
|
|
|
|
|
def _remove_notifiers(self, handler, name):
|
|
|
if name in self._trait_notifiers:
|
|
|
nlist = self._trait_notifiers[name]
|
|
|
try:
|
|
|
index = nlist.index(handler)
|
|
|
except ValueError:
|
|
|
pass
|
|
|
else:
|
|
|
del nlist[index]
|
|
|
|
|
|
def on_trait_change(self, handler, name=None, remove=False):
|
|
|
"""Setup a handler to be called when a trait changes.
|
|
|
|
|
|
This is used to setup dynamic notifications of trait changes.
|
|
|
|
|
|
Static handlers can be created by creating methods on a HasTraits
|
|
|
subclass with the naming convention '_[traitname]_changed'. Thus,
|
|
|
to create static handler for the trait 'a', create the method
|
|
|
_a_changed(self, name, old, new) (fewer arguments can be used, see
|
|
|
below).
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
handler : callable
|
|
|
A callable that is called when a trait changes. Its
|
|
|
signature can be handler(), handler(name), handler(name, new)
|
|
|
or handler(name, old, new).
|
|
|
name : list, str, None
|
|
|
If None, the handler will apply to all traits. If a list
|
|
|
of str, handler will apply to all names in the list. If a
|
|
|
str, the handler will apply just to that name.
|
|
|
remove : bool
|
|
|
If False (the default), then install the handler. If True
|
|
|
then unintall it.
|
|
|
"""
|
|
|
if remove:
|
|
|
names = parse_notifier_name(name)
|
|
|
for n in names:
|
|
|
self._remove_notifiers(handler, n)
|
|
|
else:
|
|
|
names = parse_notifier_name(name)
|
|
|
for n in names:
|
|
|
self._add_notifiers(handler, n)
|
|
|
|
|
|
@classmethod
|
|
|
def class_trait_names(cls, **metadata):
|
|
|
"""Get a list of all the names of this class' traits.
|
|
|
|
|
|
This method is just like the :meth:`trait_names` method,
|
|
|
but is unbound.
|
|
|
"""
|
|
|
return cls.class_traits(**metadata).keys()
|
|
|
|
|
|
@classmethod
|
|
|
def class_traits(cls, **metadata):
|
|
|
"""Get a `dict` of all the traits of this class. The dictionary
|
|
|
is keyed on the name and the values are the TraitType objects.
|
|
|
|
|
|
This method is just like the :meth:`traits` method, but is unbound.
|
|
|
|
|
|
The TraitTypes returned don't know anything about the values
|
|
|
that the various HasTrait's instances are holding.
|
|
|
|
|
|
The metadata kwargs allow functions to be passed in which
|
|
|
filter traits based on metadata values. The functions should
|
|
|
take a single value as an argument and return a boolean. If
|
|
|
any function returns False, then the trait is not included in
|
|
|
the output. This does not allow for any simple way of
|
|
|
testing that a metadata name exists and has any
|
|
|
value because get_metadata returns None if a metadata key
|
|
|
doesn't exist.
|
|
|
"""
|
|
|
traits = dict([memb for memb in getmembers(cls) if
|
|
|
isinstance(memb[1], TraitType)])
|
|
|
|
|
|
if len(metadata) == 0:
|
|
|
return traits
|
|
|
|
|
|
for meta_name, meta_eval in metadata.items():
|
|
|
if type(meta_eval) is not FunctionType:
|
|
|
metadata[meta_name] = _SimpleTest(meta_eval)
|
|
|
|
|
|
result = {}
|
|
|
for name, trait in traits.items():
|
|
|
for meta_name, meta_eval in metadata.items():
|
|
|
if not meta_eval(trait.get_metadata(meta_name)):
|
|
|
break
|
|
|
else:
|
|
|
result[name] = trait
|
|
|
|
|
|
return result
|
|
|
|
|
|
def trait_names(self, **metadata):
|
|
|
"""Get a list of all the names of this class' traits."""
|
|
|
return self.traits(**metadata).keys()
|
|
|
|
|
|
def traits(self, **metadata):
|
|
|
"""Get a `dict` of all the traits of this class. The dictionary
|
|
|
is keyed on the name and the values are the TraitType objects.
|
|
|
|
|
|
The TraitTypes returned don't know anything about the values
|
|
|
that the various HasTrait's instances are holding.
|
|
|
|
|
|
The metadata kwargs allow functions to be passed in which
|
|
|
filter traits based on metadata values. The functions should
|
|
|
take a single value as an argument and return a boolean. If
|
|
|
any function returns False, then the trait is not included in
|
|
|
the output. This does not allow for any simple way of
|
|
|
testing that a metadata name exists and has any
|
|
|
value because get_metadata returns None if a metadata key
|
|
|
doesn't exist.
|
|
|
"""
|
|
|
traits = dict([memb for memb in getmembers(self.__class__) if
|
|
|
isinstance(memb[1], TraitType)])
|
|
|
|
|
|
if len(metadata) == 0:
|
|
|
return traits
|
|
|
|
|
|
for meta_name, meta_eval in metadata.items():
|
|
|
if type(meta_eval) is not FunctionType:
|
|
|
metadata[meta_name] = _SimpleTest(meta_eval)
|
|
|
|
|
|
result = {}
|
|
|
for name, trait in traits.items():
|
|
|
for meta_name, meta_eval in metadata.items():
|
|
|
if not meta_eval(trait.get_metadata(meta_name)):
|
|
|
break
|
|
|
else:
|
|
|
result[name] = trait
|
|
|
|
|
|
return result
|
|
|
|
|
|
def trait_metadata(self, traitname, key, default=None):
|
|
|
"""Get metadata values for trait by key."""
|
|
|
try:
|
|
|
trait = getattr(self.__class__, traitname)
|
|
|
except AttributeError:
|
|
|
raise TraitError("Class %s does not have a trait named %s" %
|
|
|
(self.__class__.__name__, traitname))
|
|
|
else:
|
|
|
return trait.get_metadata(key, default)
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Actual TraitTypes implementations/subclasses
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# TraitTypes subclasses for handling classes and instances of classes
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
|
|
|
class ClassBasedTraitType(TraitType):
|
|
|
"""A trait with error reporting for Type, Instance and This."""
|
|
|
|
|
|
def error(self, obj, value):
|
|
|
kind = type(value)
|
|
|
if (not py3compat.PY3) and kind is InstanceType:
|
|
|
msg = 'class %s' % value.__class__.__name__
|
|
|
else:
|
|
|
msg = '%s (i.e. %s)' % ( str( kind )[1:-1], repr( value ) )
|
|
|
|
|
|
if obj is not None:
|
|
|
e = "The '%s' trait of %s instance must be %s, but a value of %s was specified." \
|
|
|
% (self.name, class_of(obj),
|
|
|
self.info(), msg)
|
|
|
else:
|
|
|
e = "The '%s' trait must be %s, but a value of %r was specified." \
|
|
|
% (self.name, self.info(), msg)
|
|
|
|
|
|
raise TraitError(e)
|
|
|
|
|
|
|
|
|
class Type(ClassBasedTraitType):
|
|
|
"""A trait whose value must be a subclass of a specified class."""
|
|
|
|
|
|
def __init__ (self, default_value=None, klass=None, allow_none=True, **metadata ):
|
|
|
"""Construct a Type trait
|
|
|
|
|
|
A Type trait specifies that its values must be subclasses of
|
|
|
a particular class.
|
|
|
|
|
|
If only ``default_value`` is given, it is used for the ``klass`` as
|
|
|
well.
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
default_value : class, str or None
|
|
|
The default value must be a subclass of klass. If an str,
|
|
|
the str must be a fully specified class name, like 'foo.bar.Bah'.
|
|
|
The string is resolved into real class, when the parent
|
|
|
:class:`HasTraits` class is instantiated.
|
|
|
klass : class, str, None
|
|
|
Values of this trait must be a subclass of klass. The klass
|
|
|
may be specified in a string like: 'foo.bar.MyClass'.
|
|
|
The string is resolved into real class, when the parent
|
|
|
:class:`HasTraits` class is instantiated.
|
|
|
allow_none : boolean
|
|
|
Indicates whether None is allowed as an assignable value. Even if
|
|
|
``False``, the default value may be ``None``.
|
|
|
"""
|
|
|
if default_value is None:
|
|
|
if klass is None:
|
|
|
klass = object
|
|
|
elif klass is None:
|
|
|
klass = default_value
|
|
|
|
|
|
if not (inspect.isclass(klass) or isinstance(klass, py3compat.string_types)):
|
|
|
raise TraitError("A Type trait must specify a class.")
|
|
|
|
|
|
self.klass = klass
|
|
|
|
|
|
super(Type, self).__init__(default_value, allow_none=allow_none, **metadata)
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
"""Validates that the value is a valid object instance."""
|
|
|
if isinstance(value, py3compat.string_types):
|
|
|
try:
|
|
|
value = import_item(value)
|
|
|
except ImportError:
|
|
|
raise TraitError("The '%s' trait of %s instance must be a type, but "
|
|
|
"%r could not be imported" % (self.name, obj, value))
|
|
|
try:
|
|
|
if issubclass(value, self.klass):
|
|
|
return value
|
|
|
except:
|
|
|
pass
|
|
|
|
|
|
self.error(obj, value)
|
|
|
|
|
|
def info(self):
|
|
|
""" Returns a description of the trait."""
|
|
|
if isinstance(self.klass, py3compat.string_types):
|
|
|
klass = self.klass
|
|
|
else:
|
|
|
klass = self.klass.__name__
|
|
|
result = 'a subclass of ' + klass
|
|
|
if self.allow_none:
|
|
|
return result + ' or None'
|
|
|
return result
|
|
|
|
|
|
def instance_init(self, obj):
|
|
|
self._resolve_classes()
|
|
|
super(Type, self).instance_init(obj)
|
|
|
|
|
|
def _resolve_classes(self):
|
|
|
if isinstance(self.klass, py3compat.string_types):
|
|
|
self.klass = import_item(self.klass)
|
|
|
if isinstance(self.default_value, py3compat.string_types):
|
|
|
self.default_value = import_item(self.default_value)
|
|
|
|
|
|
def get_default_value(self):
|
|
|
return self.default_value
|
|
|
|
|
|
|
|
|
class DefaultValueGenerator(object):
|
|
|
"""A class for generating new default value instances."""
|
|
|
|
|
|
def __init__(self, *args, **kw):
|
|
|
self.args = args
|
|
|
self.kw = kw
|
|
|
|
|
|
def generate(self, klass):
|
|
|
return klass(*self.args, **self.kw)
|
|
|
|
|
|
|
|
|
class Instance(ClassBasedTraitType):
|
|
|
"""A trait whose value must be an instance of a specified class.
|
|
|
|
|
|
The value can also be an instance of a subclass of the specified class.
|
|
|
|
|
|
Subclasses can declare default classes by overriding the klass attribute
|
|
|
"""
|
|
|
|
|
|
klass = None
|
|
|
|
|
|
def __init__(self, klass=None, args=None, kw=None,
|
|
|
allow_none=True, **metadata ):
|
|
|
"""Construct an Instance trait.
|
|
|
|
|
|
This trait allows values that are instances of a particular
|
|
|
class or its sublclasses. Our implementation is quite different
|
|
|
from that of enthough.traits as we don't allow instances to be used
|
|
|
for klass and we handle the ``args`` and ``kw`` arguments differently.
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
klass : class, str
|
|
|
The class that forms the basis for the trait. Class names
|
|
|
can also be specified as strings, like 'foo.bar.Bar'.
|
|
|
args : tuple
|
|
|
Positional arguments for generating the default value.
|
|
|
kw : dict
|
|
|
Keyword arguments for generating the default value.
|
|
|
allow_none : bool
|
|
|
Indicates whether None is allowed as a value.
|
|
|
|
|
|
Notes
|
|
|
-----
|
|
|
If both ``args`` and ``kw`` are None, then the default value is None.
|
|
|
If ``args`` is a tuple and ``kw`` is a dict, then the default is
|
|
|
created as ``klass(*args, **kw)``. If exactly one of ``args`` or ``kw`` is
|
|
|
None, the None is replaced by ``()`` or ``{}``, respectively.
|
|
|
"""
|
|
|
if klass is None:
|
|
|
klass = self.klass
|
|
|
|
|
|
if (klass is not None) and (inspect.isclass(klass) or isinstance(klass, py3compat.string_types)):
|
|
|
self.klass = klass
|
|
|
else:
|
|
|
raise TraitError('The klass attribute must be a class'
|
|
|
' not: %r' % klass)
|
|
|
|
|
|
# self.klass is a class, so handle default_value
|
|
|
if args is None and kw is None:
|
|
|
default_value = None
|
|
|
else:
|
|
|
if args is None:
|
|
|
# kw is not None
|
|
|
args = ()
|
|
|
elif kw is None:
|
|
|
# args is not None
|
|
|
kw = {}
|
|
|
|
|
|
if not isinstance(kw, dict):
|
|
|
raise TraitError("The 'kw' argument must be a dict or None.")
|
|
|
if not isinstance(args, tuple):
|
|
|
raise TraitError("The 'args' argument must be a tuple or None.")
|
|
|
|
|
|
default_value = DefaultValueGenerator(*args, **kw)
|
|
|
|
|
|
super(Instance, self).__init__(default_value, allow_none=allow_none, **metadata)
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, self.klass):
|
|
|
return value
|
|
|
else:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
def info(self):
|
|
|
if isinstance(self.klass, py3compat.string_types):
|
|
|
klass = self.klass
|
|
|
else:
|
|
|
klass = self.klass.__name__
|
|
|
result = class_of(klass)
|
|
|
if self.allow_none:
|
|
|
return result + ' or None'
|
|
|
|
|
|
return result
|
|
|
|
|
|
def instance_init(self, obj):
|
|
|
self._resolve_classes()
|
|
|
super(Instance, self).instance_init(obj)
|
|
|
|
|
|
def _resolve_classes(self):
|
|
|
if isinstance(self.klass, py3compat.string_types):
|
|
|
self.klass = import_item(self.klass)
|
|
|
|
|
|
def get_default_value(self):
|
|
|
"""Instantiate a default value instance.
|
|
|
|
|
|
This is called when the containing HasTraits classes'
|
|
|
:meth:`__new__` method is called to ensure that a unique instance
|
|
|
is created for each HasTraits instance.
|
|
|
"""
|
|
|
dv = self.default_value
|
|
|
if isinstance(dv, DefaultValueGenerator):
|
|
|
return dv.generate(self.klass)
|
|
|
else:
|
|
|
return dv
|
|
|
|
|
|
|
|
|
class This(ClassBasedTraitType):
|
|
|
"""A trait for instances of the class containing this trait.
|
|
|
|
|
|
Because how how and when class bodies are executed, the ``This``
|
|
|
trait can only have a default value of None. This, and because we
|
|
|
always validate default values, ``allow_none`` is *always* true.
|
|
|
"""
|
|
|
|
|
|
info_text = 'an instance of the same type as the receiver or None'
|
|
|
|
|
|
def __init__(self, **metadata):
|
|
|
super(This, self).__init__(None, **metadata)
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
# What if value is a superclass of obj.__class__? This is
|
|
|
# complicated if it was the superclass that defined the This
|
|
|
# trait.
|
|
|
if isinstance(value, self.this_class) or (value is None):
|
|
|
return value
|
|
|
else:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Basic TraitTypes implementations/subclasses
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
|
|
|
class Any(TraitType):
|
|
|
default_value = None
|
|
|
info_text = 'any value'
|
|
|
|
|
|
|
|
|
class Int(TraitType):
|
|
|
"""An int trait."""
|
|
|
|
|
|
default_value = 0
|
|
|
info_text = 'an int'
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, int):
|
|
|
return value
|
|
|
self.error(obj, value)
|
|
|
|
|
|
class CInt(Int):
|
|
|
"""A casting version of the int trait."""
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
try:
|
|
|
return int(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
if py3compat.PY3:
|
|
|
Long, CLong = Int, CInt
|
|
|
Integer = Int
|
|
|
else:
|
|
|
class Long(TraitType):
|
|
|
"""A long integer trait."""
|
|
|
|
|
|
default_value = 0
|
|
|
info_text = 'a long'
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, long):
|
|
|
return value
|
|
|
if isinstance(value, int):
|
|
|
return long(value)
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class CLong(Long):
|
|
|
"""A casting version of the long integer trait."""
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
try:
|
|
|
return long(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
class Integer(TraitType):
|
|
|
"""An integer trait.
|
|
|
|
|
|
Longs that are unnecessary (<= sys.maxint) are cast to ints."""
|
|
|
|
|
|
default_value = 0
|
|
|
info_text = 'an integer'
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, int):
|
|
|
return value
|
|
|
if isinstance(value, long):
|
|
|
# downcast longs that fit in int:
|
|
|
# note that int(n > sys.maxint) returns a long, so
|
|
|
# we don't need a condition on this cast
|
|
|
return int(value)
|
|
|
if sys.platform == "cli":
|
|
|
from System import Int64
|
|
|
if isinstance(value, Int64):
|
|
|
return int(value)
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class Float(TraitType):
|
|
|
"""A float trait."""
|
|
|
|
|
|
default_value = 0.0
|
|
|
info_text = 'a float'
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, float):
|
|
|
return value
|
|
|
if isinstance(value, int):
|
|
|
return float(value)
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class CFloat(Float):
|
|
|
"""A casting version of the float trait."""
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
try:
|
|
|
return float(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
class Complex(TraitType):
|
|
|
"""A trait for complex numbers."""
|
|
|
|
|
|
default_value = 0.0 + 0.0j
|
|
|
info_text = 'a complex number'
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, complex):
|
|
|
return value
|
|
|
if isinstance(value, (float, int)):
|
|
|
return complex(value)
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class CComplex(Complex):
|
|
|
"""A casting version of the complex number trait."""
|
|
|
|
|
|
def validate (self, obj, value):
|
|
|
try:
|
|
|
return complex(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
# We should always be explicit about whether we're using bytes or unicode, both
|
|
|
# for Python 3 conversion and for reliable unicode behaviour on Python 2. So
|
|
|
# we don't have a Str type.
|
|
|
class Bytes(TraitType):
|
|
|
"""A trait for byte strings."""
|
|
|
|
|
|
default_value = b''
|
|
|
info_text = 'a bytes object'
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, bytes):
|
|
|
return value
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class CBytes(Bytes):
|
|
|
"""A casting version of the byte string trait."""
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
try:
|
|
|
return bytes(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class Unicode(TraitType):
|
|
|
"""A trait for unicode strings."""
|
|
|
|
|
|
default_value = u''
|
|
|
info_text = 'a unicode string'
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, py3compat.unicode_type):
|
|
|
return value
|
|
|
if isinstance(value, bytes):
|
|
|
try:
|
|
|
return value.decode('ascii', 'strict')
|
|
|
except UnicodeDecodeError:
|
|
|
msg = "Could not decode {!r} for unicode trait '{}' of {} instance."
|
|
|
raise TraitError(msg.format(value, self.name, class_of(obj)))
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class CUnicode(Unicode):
|
|
|
"""A casting version of the unicode trait."""
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
try:
|
|
|
return py3compat.unicode_type(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class ObjectName(TraitType):
|
|
|
"""A string holding a valid object name in this version of Python.
|
|
|
|
|
|
This does not check that the name exists in any scope."""
|
|
|
info_text = "a valid object identifier in Python"
|
|
|
|
|
|
if py3compat.PY3:
|
|
|
# Python 3:
|
|
|
coerce_str = staticmethod(lambda _,s: s)
|
|
|
|
|
|
else:
|
|
|
# Python 2:
|
|
|
def coerce_str(self, obj, value):
|
|
|
"In Python 2, coerce ascii-only unicode to str"
|
|
|
if isinstance(value, unicode):
|
|
|
try:
|
|
|
return str(value)
|
|
|
except UnicodeEncodeError:
|
|
|
self.error(obj, value)
|
|
|
return value
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
value = self.coerce_str(obj, value)
|
|
|
|
|
|
if isinstance(value, string_types) and py3compat.isidentifier(value):
|
|
|
return value
|
|
|
self.error(obj, value)
|
|
|
|
|
|
class DottedObjectName(ObjectName):
|
|
|
"""A string holding a valid dotted object name in Python, such as A.b3._c"""
|
|
|
def validate(self, obj, value):
|
|
|
value = self.coerce_str(obj, value)
|
|
|
|
|
|
if isinstance(value, string_types) and py3compat.isidentifier(value, dotted=True):
|
|
|
return value
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class Bool(TraitType):
|
|
|
"""A boolean (True, False) trait."""
|
|
|
|
|
|
default_value = False
|
|
|
info_text = 'a boolean'
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, bool):
|
|
|
return value
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class CBool(Bool):
|
|
|
"""A casting version of the boolean trait."""
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
try:
|
|
|
return bool(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class Enum(TraitType):
|
|
|
"""An enum that whose value must be in a given sequence."""
|
|
|
|
|
|
def __init__(self, values, default_value=None, allow_none=True, **metadata):
|
|
|
self.values = values
|
|
|
super(Enum, self).__init__(default_value, allow_none=allow_none, **metadata)
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if value in self.values:
|
|
|
return value
|
|
|
self.error(obj, value)
|
|
|
|
|
|
def info(self):
|
|
|
""" Returns a description of the trait."""
|
|
|
result = 'any of ' + repr(self.values)
|
|
|
if self.allow_none:
|
|
|
return result + ' or None'
|
|
|
return result
|
|
|
|
|
|
class CaselessStrEnum(Enum):
|
|
|
"""An enum of strings that are caseless in validate."""
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if not isinstance(value, py3compat.string_types):
|
|
|
self.error(obj, value)
|
|
|
|
|
|
for v in self.values:
|
|
|
if v.lower() == value.lower():
|
|
|
return v
|
|
|
self.error(obj, value)
|
|
|
|
|
|
class Container(Instance):
|
|
|
"""An instance of a container (list, set, etc.)
|
|
|
|
|
|
To be subclassed by overriding klass.
|
|
|
"""
|
|
|
klass = None
|
|
|
_cast_types = ()
|
|
|
_valid_defaults = SequenceTypes
|
|
|
_trait = None
|
|
|
|
|
|
def __init__(self, trait=None, default_value=None, allow_none=True,
|
|
|
**metadata):
|
|
|
"""Create a container trait type from a list, set, or tuple.
|
|
|
|
|
|
The default value is created by doing ``List(default_value)``,
|
|
|
which creates a copy of the ``default_value``.
|
|
|
|
|
|
``trait`` can be specified, which restricts the type of elements
|
|
|
in the container to that TraitType.
|
|
|
|
|
|
If only one arg is given and it is not a Trait, it is taken as
|
|
|
``default_value``:
|
|
|
|
|
|
``c = List([1,2,3])``
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
|
|
|
trait : TraitType [ optional ]
|
|
|
the type for restricting the contents of the Container. If unspecified,
|
|
|
types are not checked.
|
|
|
|
|
|
default_value : SequenceType [ optional ]
|
|
|
The default value for the Trait. Must be list/tuple/set, and
|
|
|
will be cast to the container type.
|
|
|
|
|
|
allow_none : Bool [ default True ]
|
|
|
Whether to allow the value to be None
|
|
|
|
|
|
**metadata : any
|
|
|
further keys for extensions to the Trait (e.g. config)
|
|
|
|
|
|
"""
|
|
|
# allow List([values]):
|
|
|
if default_value is None and not is_trait(trait):
|
|
|
default_value = trait
|
|
|
trait = None
|
|
|
|
|
|
if default_value is None:
|
|
|
args = ()
|
|
|
elif isinstance(default_value, self._valid_defaults):
|
|
|
args = (default_value,)
|
|
|
else:
|
|
|
raise TypeError('default value of %s was %s' %(self.__class__.__name__, default_value))
|
|
|
|
|
|
if is_trait(trait):
|
|
|
self._trait = trait() if isinstance(trait, type) else trait
|
|
|
self._trait.name = 'element'
|
|
|
elif trait is not None:
|
|
|
raise TypeError("`trait` must be a Trait or None, got %s"%repr_type(trait))
|
|
|
|
|
|
super(Container,self).__init__(klass=self.klass, args=args,
|
|
|
allow_none=allow_none, **metadata)
|
|
|
|
|
|
def element_error(self, obj, element, validator):
|
|
|
e = "Element of the '%s' trait of %s instance must be %s, but a value of %s was specified." \
|
|
|
% (self.name, class_of(obj), validator.info(), repr_type(element))
|
|
|
raise TraitError(e)
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, self._cast_types):
|
|
|
value = self.klass(value)
|
|
|
value = super(Container, self).validate(obj, value)
|
|
|
if value is None:
|
|
|
return value
|
|
|
|
|
|
value = self.validate_elements(obj, value)
|
|
|
|
|
|
return value
|
|
|
|
|
|
def validate_elements(self, obj, value):
|
|
|
validated = []
|
|
|
if self._trait is None or isinstance(self._trait, Any):
|
|
|
return value
|
|
|
for v in value:
|
|
|
try:
|
|
|
v = self._trait._validate(obj, v)
|
|
|
except TraitError:
|
|
|
self.element_error(obj, v, self._trait)
|
|
|
else:
|
|
|
validated.append(v)
|
|
|
return self.klass(validated)
|
|
|
|
|
|
def instance_init(self, obj):
|
|
|
if isinstance(self._trait, Instance):
|
|
|
self._trait._resolve_classes()
|
|
|
super(Container, self).instance_init(obj)
|
|
|
|
|
|
|
|
|
class List(Container):
|
|
|
"""An instance of a Python list."""
|
|
|
klass = list
|
|
|
_cast_types = (tuple,)
|
|
|
|
|
|
def __init__(self, trait=None, default_value=None, minlen=0, maxlen=sys.maxsize,
|
|
|
allow_none=True, **metadata):
|
|
|
"""Create a List trait type from a list, set, or tuple.
|
|
|
|
|
|
The default value is created by doing ``List(default_value)``,
|
|
|
which creates a copy of the ``default_value``.
|
|
|
|
|
|
``trait`` can be specified, which restricts the type of elements
|
|
|
in the container to that TraitType.
|
|
|
|
|
|
If only one arg is given and it is not a Trait, it is taken as
|
|
|
``default_value``:
|
|
|
|
|
|
``c = List([1,2,3])``
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
|
|
|
trait : TraitType [ optional ]
|
|
|
the type for restricting the contents of the Container. If unspecified,
|
|
|
types are not checked.
|
|
|
|
|
|
default_value : SequenceType [ optional ]
|
|
|
The default value for the Trait. Must be list/tuple/set, and
|
|
|
will be cast to the container type.
|
|
|
|
|
|
minlen : Int [ default 0 ]
|
|
|
The minimum length of the input list
|
|
|
|
|
|
maxlen : Int [ default sys.maxsize ]
|
|
|
The maximum length of the input list
|
|
|
|
|
|
allow_none : Bool [ default True ]
|
|
|
Whether to allow the value to be None
|
|
|
|
|
|
**metadata : any
|
|
|
further keys for extensions to the Trait (e.g. config)
|
|
|
|
|
|
"""
|
|
|
self._minlen = minlen
|
|
|
self._maxlen = maxlen
|
|
|
super(List, self).__init__(trait=trait, default_value=default_value,
|
|
|
allow_none=allow_none, **metadata)
|
|
|
|
|
|
def length_error(self, obj, value):
|
|
|
e = "The '%s' trait of %s instance must be of length %i <= L <= %i, but a value of %s was specified." \
|
|
|
% (self.name, class_of(obj), self._minlen, self._maxlen, value)
|
|
|
raise TraitError(e)
|
|
|
|
|
|
def validate_elements(self, obj, value):
|
|
|
length = len(value)
|
|
|
if length < self._minlen or length > self._maxlen:
|
|
|
self.length_error(obj, value)
|
|
|
|
|
|
return super(List, self).validate_elements(obj, value)
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
value = super(List, self).validate(obj, value)
|
|
|
|
|
|
value = self.validate_elements(obj, value)
|
|
|
|
|
|
return value
|
|
|
|
|
|
|
|
|
|
|
|
class Set(List):
|
|
|
"""An instance of a Python set."""
|
|
|
klass = set
|
|
|
_cast_types = (tuple, list)
|
|
|
|
|
|
class Tuple(Container):
|
|
|
"""An instance of a Python tuple."""
|
|
|
klass = tuple
|
|
|
_cast_types = (list,)
|
|
|
|
|
|
def __init__(self, *traits, **metadata):
|
|
|
"""Tuple(*traits, default_value=None, allow_none=True, **medatata)
|
|
|
|
|
|
Create a tuple from a list, set, or tuple.
|
|
|
|
|
|
Create a fixed-type tuple with Traits:
|
|
|
|
|
|
``t = Tuple(Int, Str, CStr)``
|
|
|
|
|
|
would be length 3, with Int,Str,CStr for each element.
|
|
|
|
|
|
If only one arg is given and it is not a Trait, it is taken as
|
|
|
default_value:
|
|
|
|
|
|
``t = Tuple((1,2,3))``
|
|
|
|
|
|
Otherwise, ``default_value`` *must* be specified by keyword.
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
|
|
|
*traits : TraitTypes [ optional ]
|
|
|
the tsype for restricting the contents of the Tuple. If unspecified,
|
|
|
types are not checked. If specified, then each positional argument
|
|
|
corresponds to an element of the tuple. Tuples defined with traits
|
|
|
are of fixed length.
|
|
|
|
|
|
default_value : SequenceType [ optional ]
|
|
|
The default value for the Tuple. Must be list/tuple/set, and
|
|
|
will be cast to a tuple. If `traits` are specified, the
|
|
|
`default_value` must conform to the shape and type they specify.
|
|
|
|
|
|
allow_none : Bool [ default True ]
|
|
|
Whether to allow the value to be None
|
|
|
|
|
|
**metadata : any
|
|
|
further keys for extensions to the Trait (e.g. config)
|
|
|
|
|
|
"""
|
|
|
default_value = metadata.pop('default_value', None)
|
|
|
allow_none = metadata.pop('allow_none', True)
|
|
|
|
|
|
# allow Tuple((values,)):
|
|
|
if len(traits) == 1 and default_value is None and not is_trait(traits[0]):
|
|
|
default_value = traits[0]
|
|
|
traits = ()
|
|
|
|
|
|
if default_value is None:
|
|
|
args = ()
|
|
|
elif isinstance(default_value, self._valid_defaults):
|
|
|
args = (default_value,)
|
|
|
else:
|
|
|
raise TypeError('default value of %s was %s' %(self.__class__.__name__, default_value))
|
|
|
|
|
|
self._traits = []
|
|
|
for trait in traits:
|
|
|
t = trait() if isinstance(trait, type) else trait
|
|
|
t.name = 'element'
|
|
|
self._traits.append(t)
|
|
|
|
|
|
if self._traits and default_value is None:
|
|
|
# don't allow default to be an empty container if length is specified
|
|
|
args = None
|
|
|
super(Container,self).__init__(klass=self.klass, args=args,
|
|
|
allow_none=allow_none, **metadata)
|
|
|
|
|
|
def validate_elements(self, obj, value):
|
|
|
if not self._traits:
|
|
|
# nothing to validate
|
|
|
return value
|
|
|
if len(value) != len(self._traits):
|
|
|
e = "The '%s' trait of %s instance requires %i elements, but a value of %s was specified." \
|
|
|
% (self.name, class_of(obj), len(self._traits), repr_type(value))
|
|
|
raise TraitError(e)
|
|
|
|
|
|
validated = []
|
|
|
for t,v in zip(self._traits, value):
|
|
|
try:
|
|
|
v = t._validate(obj, v)
|
|
|
except TraitError:
|
|
|
self.element_error(obj, v, t)
|
|
|
else:
|
|
|
validated.append(v)
|
|
|
return tuple(validated)
|
|
|
|
|
|
|
|
|
class Dict(Instance):
|
|
|
"""An instance of a Python dict."""
|
|
|
|
|
|
def __init__(self, default_value=None, allow_none=True, **metadata):
|
|
|
"""Create a dict trait type from a dict.
|
|
|
|
|
|
The default value is created by doing ``dict(default_value)``,
|
|
|
which creates a copy of the ``default_value``.
|
|
|
"""
|
|
|
if default_value is None:
|
|
|
args = ((),)
|
|
|
elif isinstance(default_value, dict):
|
|
|
args = (default_value,)
|
|
|
elif isinstance(default_value, SequenceTypes):
|
|
|
args = (default_value,)
|
|
|
else:
|
|
|
raise TypeError('default value of Dict was %s' % default_value)
|
|
|
|
|
|
super(Dict,self).__init__(klass=dict, args=args,
|
|
|
allow_none=allow_none, **metadata)
|
|
|
|
|
|
|
|
|
class EventfulDict(Instance):
|
|
|
"""An instance of an EventfulDict."""
|
|
|
|
|
|
def __init__(self, default_value=None, allow_none=True, **metadata):
|
|
|
"""Create a EventfulDict trait type from a dict.
|
|
|
|
|
|
The default value is created by doing
|
|
|
``eventful.EvenfulDict(default_value)``, which creates a copy of the
|
|
|
``default_value``.
|
|
|
"""
|
|
|
if default_value is None:
|
|
|
args = ((),)
|
|
|
elif isinstance(default_value, dict):
|
|
|
args = (default_value,)
|
|
|
elif isinstance(default_value, SequenceTypes):
|
|
|
args = (default_value,)
|
|
|
else:
|
|
|
raise TypeError('default value of EventfulDict was %s' % default_value)
|
|
|
|
|
|
super(EventfulDict, self).__init__(klass=eventful.EventfulDict, args=args,
|
|
|
allow_none=allow_none, **metadata)
|
|
|
|
|
|
|
|
|
class EventfulList(Instance):
|
|
|
"""An instance of an EventfulList."""
|
|
|
|
|
|
def __init__(self, default_value=None, allow_none=True, **metadata):
|
|
|
"""Create a EventfulList trait type from a dict.
|
|
|
|
|
|
The default value is created by doing
|
|
|
``eventful.EvenfulList(default_value)``, which creates a copy of the
|
|
|
``default_value``.
|
|
|
"""
|
|
|
if default_value is None:
|
|
|
args = ((),)
|
|
|
else:
|
|
|
args = (default_value,)
|
|
|
|
|
|
super(EventfulList, self).__init__(klass=eventful.EventfulList, args=args,
|
|
|
allow_none=allow_none, **metadata)
|
|
|
|
|
|
|
|
|
class TCPAddress(TraitType):
|
|
|
"""A trait for an (ip, port) tuple.
|
|
|
|
|
|
This allows for both IPv4 IP addresses as well as hostnames.
|
|
|
"""
|
|
|
|
|
|
default_value = ('127.0.0.1', 0)
|
|
|
info_text = 'an (ip, port) tuple'
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, tuple):
|
|
|
if len(value) == 2:
|
|
|
if isinstance(value[0], py3compat.string_types) and isinstance(value[1], int):
|
|
|
port = value[1]
|
|
|
if port >= 0 and port <= 65535:
|
|
|
return value
|
|
|
self.error(obj, value)
|
|
|
|
|
|
class CRegExp(TraitType):
|
|
|
"""A casting compiled regular expression trait.
|
|
|
|
|
|
Accepts both strings and compiled regular expressions. The resulting
|
|
|
attribute will be a compiled regular expression."""
|
|
|
|
|
|
info_text = 'a regular expression'
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
try:
|
|
|
return re.compile(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
