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#!/usr/bin/env python
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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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traitlets (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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Authors:
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* Brian Granger
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* Enthought, Inc. Some of the code in this file comes from enthought.traits
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and is licensed under the BSD license. Also, many of the ideas also come
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from enthought.traits even though our implementation is very different.
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"""
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#-----------------------------------------------------------------------------
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# Copyright (C) 2008-2009 The IPython Development Team
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#
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# Distributed under the terms of the BSD License. The full license is in
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# the file COPYING, distributed as part of this software.
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#-----------------------------------------------------------------------------
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#-----------------------------------------------------------------------------
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# Imports
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#-----------------------------------------------------------------------------
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import inspect
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import sys
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import types
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from types import (
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InstanceType, ClassType, FunctionType,
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ListType, TupleType
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)
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from IPython.utils.importstring import import_item
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ClassTypes = (ClassType, type)
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SequenceTypes = (ListType, TupleType)
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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 TraitletError(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, basestring ):
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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 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 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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['anytraitlet']
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"""
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if isinstance(name, str):
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return [name]
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elif name is None:
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return ['anytraitlet']
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elif isinstance(name, (list, tuple)):
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for n in name:
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assert isinstance(n, str), "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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#-----------------------------------------------------------------------------
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# Base TraitletType for all traitlets
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#-----------------------------------------------------------------------------
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class TraitletType(object):
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"""A base class for all traitlet descriptors.
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Notes
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-----
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Our implementation of traitlets is based on Python's descriptor
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prototol. This class is the base class for all such descriptors. The
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only magic we use is a custom metaclass for the main :class:`HasTraitlets`
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class that does the following:
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1. Sets the :attr:`name` attribute of every :class:`TraitletType`
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instance in the class dict to the name of the attribute.
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2. Sets the :attr:`this_class` attribute of every :class:`TraitletType`
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instance in the class dict to the *class* that declared the traitlet.
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This is used by the :class:`This` traitlet to allow subclasses to
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accept superclasses for :class:`This` values.
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"""
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metadata = {}
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default_value = Undefined
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info_text = 'any value'
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def __init__(self, default_value=NoDefaultSpecified, **metadata):
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"""Create a TraitletType.
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"""
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if default_value is not NoDefaultSpecified:
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self.default_value = default_value
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if len(metadata) > 0:
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if len(self.metadata) > 0:
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self._metadata = self.metadata.copy()
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self._metadata.update(metadata)
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else:
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self._metadata = metadata
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else:
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self._metadata = self.metadata
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self.init()
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def init(self):
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pass
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def get_default_value(self):
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"""Create a new instance of the default value."""
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dv = self.default_value
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return dv
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def instance_init(self, obj):
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"""This is called by :meth:`HasTraitlets.__new__` to finish init'ing.
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Some stages of initialization must be delayed until the parent
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:class:`HasTraitlets` instance has been created. This method is
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called in :meth:`HasTraitlets.__new__` after the instance has been
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created.
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This method trigger the creation and validation of default values
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and also things like the resolution of str given class names in
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:class:`Type` and :class`Instance`.
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Parameters
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----------
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obj : :class:`HasTraitlets` instance
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The parent :class:`HasTraitlets` instance that has just been
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created.
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"""
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self.set_default_value(obj)
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def set_default_value(self, obj):
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"""Set the default value on a per instance basis.
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This method is called by :meth:`instance_init` to create and
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validate the default value. The creation and validation of
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default values must be delayed until the parent :class:`HasTraitlets`
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class has been instantiated.
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"""
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dv = self.get_default_value()
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newdv = self._validate(obj, dv)
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obj._traitlet_values[self.name] = newdv
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def __get__(self, obj, cls=None):
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"""Get the value of the traitlet by self.name for the instance.
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Default values are instantiated when :meth:`HasTraitlets.__new__`
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is called. Thus by the time this method gets called either the
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default value or a user defined value (they called :meth:`__set__`)
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is in the :class:`HasTraitlets` instance.
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"""
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if obj is None:
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return self
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else:
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try:
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value = obj._traitlet_values[self.name]
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except:
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# HasTraitlets should call set_default_value to populate
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# this. So this should never be reached.
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raise TraitletError('Unexpected error in TraitletType: '
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'default value not set properly')
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else:
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return value
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def __set__(self, obj, value):
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new_value = self._validate(obj, value)
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old_value = self.__get__(obj)
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if old_value != new_value:
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obj._traitlet_values[self.name] = new_value
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obj._notify_traitlet(self.name, old_value, new_value)
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def _validate(self, obj, value):
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if hasattr(self, 'validate'):
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return self.validate(obj, value)
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elif hasattr(self, 'is_valid_for'):
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valid = self.is_valid_for(value)
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if valid:
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return value
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else:
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raise TraitletError('invalid value for type: %r' % value)
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elif hasattr(self, 'value_for'):
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return self.value_for(value)
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else:
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return value
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def info(self):
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return self.info_text
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def error(self, obj, value):
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if obj is not None:
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e = "The '%s' traitlet of %s instance must be %s, but a value of %s was specified." \
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% (self.name, class_of(obj),
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self.info(), repr_type(value))
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else:
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e = "The '%s' traitlet must be %s, but a value of %r was specified." \
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% (self.name, self.info(), repr_type(value))
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raise TraitletError(e)
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def get_metadata(self, key):
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return getattr(self, '_metadata', {}).get(key, None)
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def set_metadata(self, key, value):
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getattr(self, '_metadata', {})[key] = value
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#-----------------------------------------------------------------------------
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# The HasTraitlets implementation
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#-----------------------------------------------------------------------------
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class MetaHasTraitlets(type):
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"""A metaclass for HasTraitlets.
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This metaclass makes sure that any TraitletType class attributes are
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instantiated and sets their name attribute.
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"""
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def __new__(mcls, name, bases, classdict):
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"""Create the HasTraitlets class.
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This instantiates all TraitletTypes in the class dict and sets their
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:attr:`name` attribute.
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"""
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for k,v in classdict.iteritems():
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if isinstance(v, TraitletType):
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v.name = k
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elif inspect.isclass(v):
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if issubclass(v, TraitletType):
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vinst = v()
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vinst.name = k
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classdict[k] = vinst
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return super(MetaHasTraitlets, mcls).__new__(mcls, name, bases, classdict)
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def __init__(cls, name, bases, classdict):
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"""Finish initializing the HasTraitlets class.
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This sets the :attr:`this_class` attribute of each TraitletType in the
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class dict to the newly created class ``cls``.
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"""
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for k, v in classdict.iteritems():
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if isinstance(v, TraitletType):
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v.this_class = cls
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super(MetaHasTraitlets, cls).__init__(name, bases, classdict)
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class HasTraitlets(object):
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__metaclass__ = MetaHasTraitlets
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def __new__(cls, *args, **kw):
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inst = super(HasTraitlets, cls).__new__(cls, *args, **kw)
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inst._traitlet_values = {}
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inst._traitlet_notifiers = {}
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# Here we tell all the TraitletType instances to set their default
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# values on the instance.
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for key in dir(cls):
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value = getattr(cls, key)
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if isinstance(value, TraitletType):
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value.instance_init(inst)
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return inst
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# def __init__(self):
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# self._traitlet_values = {}
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# self._traitlet_notifiers = {}
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def _notify_traitlet(self, name, old_value, new_value):
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# First dynamic ones
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callables = self._traitlet_notifiers.get(name,[])
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more_callables = self._traitlet_notifiers.get('anytraitlet',[])
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callables.extend(more_callables)
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# Now static ones
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try:
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cb = getattr(self, '_%s_changed' % name)
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except:
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pass
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else:
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callables.append(cb)
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# Call them all now
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for c in callables:
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# Traits catches and logs errors here. I allow them to raise
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if callable(c):
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argspec = inspect.getargspec(c)
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nargs = len(argspec[0])
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# Bound methods have an additional 'self' argument
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# I don't know how to treat unbound methods, but they
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# can't really be used for callbacks.
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if isinstance(c, types.MethodType):
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offset = -1
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else:
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offset = 0
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if nargs + offset == 0:
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c()
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elif nargs + offset == 1:
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c(name)
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elif nargs + offset == 2:
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c(name, new_value)
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elif nargs + offset == 3:
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c(name, old_value, new_value)
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else:
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raise TraitletError('a traitlet changed callback '
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'must have 0-3 arguments.')
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else:
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raise TraitletError('a traitlet changed callback '
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'must be callable.')
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def _add_notifiers(self, handler, name):
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if not self._traitlet_notifiers.has_key(name):
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nlist = []
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self._traitlet_notifiers[name] = nlist
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else:
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nlist = self._traitlet_notifiers[name]
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if handler not in nlist:
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nlist.append(handler)
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def _remove_notifiers(self, handler, name):
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if self._traitlet_notifiers.has_key(name):
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nlist = self._traitlet_notifiers[name]
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try:
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index = nlist.index(handler)
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except ValueError:
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pass
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else:
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del nlist[index]
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def on_traitlet_change(self, handler, name=None, remove=False):
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"""Setup a handler to be called when a traitlet changes.
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This is used to setup dynamic notifications of traitlet changes.
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Static handlers can be created by creating methods on a HasTraitlets
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subclass with the naming convention '_[traitletname]_changed'. Thus,
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to create static handler for the traitlet 'a', create the method
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_a_changed(self, name, old, new) (fewer arguments can be used, see
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below).
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Parameters
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----------
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handler : callable
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A callable that is called when a traitlet changes. Its
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signature can be handler(), handler(name), handler(name, new)
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or handler(name, old, new).
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name : list, str, None
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If None, the handler will apply to all traitlets. If a list
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of str, handler will apply to all names in the list. If a
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str, the handler will apply just to that name.
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remove : bool
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If False (the default), then install the handler. If True
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then unintall it.
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"""
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if remove:
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names = parse_notifier_name(name)
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for n in names:
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self._remove_notifiers(handler, n)
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else:
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names = parse_notifier_name(name)
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for n in names:
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self._add_notifiers(handler, n)
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def traitlet_names(self, **metadata):
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|
"""Get a list of all the names of this classes traitlets."""
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return self.traitlets(**metadata).keys()
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def traitlets(self, *args, **metadata):
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|
|
"""Get a list of all the traitlets of this class.
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The TraitletTypes returned don't know anything about the values
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that the various HasTraitlet's instances are holding.
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"""
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|
|
traitlets = dict([memb for memb in inspect.getmembers(self.__class__) if \
|
|
|
isinstance(memb[1], TraitletType)])
|
|
|
if len(metadata) == 0 and len(args) == 0:
|
|
|
return traitlets
|
|
|
|
|
|
for meta_name in args:
|
|
|
metadata[meta_name] = lambda _: True
|
|
|
|
|
|
for meta_name, meta_eval in metadata.items():
|
|
|
if type(meta_eval) is not FunctionType:
|
|
|
metadata[meta_name] = _SimpleTest(meta_eval)
|
|
|
|
|
|
result = {}
|
|
|
for name, traitlet in traitlets.items():
|
|
|
for meta_name, meta_eval in metadata.items():
|
|
|
if not meta_eval(traitlet.get_metadata(meta_name)):
|
|
|
break
|
|
|
else:
|
|
|
result[name] = traitlet
|
|
|
|
|
|
return result
|
|
|
|
|
|
def traitlet_metadata(self, traitletname, key):
|
|
|
"""Get metadata values for traitlet by key."""
|
|
|
try:
|
|
|
traitlet = getattr(self.__class__, traitletname)
|
|
|
except AttributeError:
|
|
|
raise TraitletError("Class %s does not have a traitlet named %s" %
|
|
|
(self.__class__.__name__, traitletname))
|
|
|
else:
|
|
|
return traitlet.get_metadata(key)
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Actual TraitletTypes implementations/subclasses
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# TraitletTypes subclasses for handling classes and instances of classes
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
|
|
|
class ClassBasedTraitletType(TraitletType):
|
|
|
"""A traitlet with error reporting for Type, Instance and This."""
|
|
|
|
|
|
def error(self, obj, value):
|
|
|
kind = type(value)
|
|
|
if kind is InstanceType:
|
|
|
msg = 'class %s' % value.__class__.__name__
|
|
|
else:
|
|
|
msg = '%s (i.e. %s)' % ( str( kind )[1:-1], repr( value ) )
|
|
|
|
|
|
super(ClassBasedTraitletType, self).error(obj, msg)
|
|
|
|
|
|
|
|
|
class Type(ClassBasedTraitletType):
|
|
|
"""A traitlet 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 traitlet
|
|
|
|
|
|
A Type traitlet 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:`HasTraitlets` class is instantiated.
|
|
|
klass : class, str, None
|
|
|
Values of this traitlet 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:`HasTraitlets` 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, basestring)):
|
|
|
raise TraitletError("A Type traitlet must specify a class.")
|
|
|
|
|
|
self.klass = klass
|
|
|
self._allow_none = allow_none
|
|
|
|
|
|
super(Type, self).__init__(default_value, **metadata)
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
"""Validates that the value is a valid object instance."""
|
|
|
try:
|
|
|
if issubclass(value, self.klass):
|
|
|
return value
|
|
|
except:
|
|
|
if (value is None) and (self._allow_none):
|
|
|
return value
|
|
|
|
|
|
self.error(obj, value)
|
|
|
|
|
|
def info(self):
|
|
|
""" Returns a description of the trait."""
|
|
|
if isinstance(self.klass, basestring):
|
|
|
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, basestring):
|
|
|
self.klass = import_item(self.klass)
|
|
|
if isinstance(self.default_value, basestring):
|
|
|
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(ClassBasedTraitletType):
|
|
|
"""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.
|
|
|
"""
|
|
|
|
|
|
def __init__(self, klass=None, args=None, kw=None,
|
|
|
allow_none=True, **metadata ):
|
|
|
"""Construct an Instance traitlet.
|
|
|
|
|
|
This traitlet 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 traitlet. 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.
|
|
|
|
|
|
Default Value
|
|
|
-------------
|
|
|
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 either ``args`` or ``kw`` is
|
|
|
not (but not both), None is replace by ``()`` or ``{}``.
|
|
|
"""
|
|
|
|
|
|
self._allow_none = allow_none
|
|
|
|
|
|
if (klass is None) or (not (inspect.isclass(klass) or isinstance(klass, basestring))):
|
|
|
raise TraitletError('The klass argument must be a class'
|
|
|
' you gave: %r' % klass)
|
|
|
self.klass = 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 TraitletError("The 'kw' argument must be a dict or None.")
|
|
|
if not isinstance(args, tuple):
|
|
|
raise TraitletError("The 'args' argument must be a tuple or None.")
|
|
|
|
|
|
default_value = DefaultValueGenerator(*args, **kw)
|
|
|
|
|
|
super(Instance, self).__init__(default_value, **metadata)
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if value is None:
|
|
|
if self._allow_none:
|
|
|
return value
|
|
|
self.error(obj, value)
|
|
|
|
|
|
if isinstance(value, self.klass):
|
|
|
return value
|
|
|
else:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
def info(self):
|
|
|
if isinstance(self.klass, basestring):
|
|
|
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, basestring):
|
|
|
self.klass = import_item(self.klass)
|
|
|
|
|
|
def get_default_value(self):
|
|
|
"""Instantiate a default value instance.
|
|
|
|
|
|
This is called when the containing HasTraitlets classes'
|
|
|
:meth:`__new__` method is called to ensure that a unique instance
|
|
|
is created for each HasTraitlets instance.
|
|
|
"""
|
|
|
dv = self.default_value
|
|
|
if isinstance(dv, DefaultValueGenerator):
|
|
|
return dv.generate(self.klass)
|
|
|
else:
|
|
|
return dv
|
|
|
|
|
|
|
|
|
class This(ClassBasedTraitletType):
|
|
|
"""A traitlet for instances of the class containing this trait.
|
|
|
|
|
|
Because how how and when class bodies are executed, the ``This``
|
|
|
traitlet 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
|
|
|
# traitlet.
|
|
|
if isinstance(value, self.this_class) or (value is None):
|
|
|
return value
|
|
|
else:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Basic TraitletTypes implementations/subclasses
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
|
|
|
class Any(TraitletType):
|
|
|
default_value = None
|
|
|
info_text = 'any value'
|
|
|
|
|
|
|
|
|
class Int(TraitletType):
|
|
|
"""A integer traitlet."""
|
|
|
|
|
|
evaluate = int
|
|
|
default_value = 0
|
|
|
info_text = 'an integer'
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, int):
|
|
|
return value
|
|
|
self.error(obj, value)
|
|
|
|
|
|
class CInt(Int):
|
|
|
"""A casting version of the int traitlet."""
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
try:
|
|
|
return int(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class Long(TraitletType):
|
|
|
"""A long integer traitlet."""
|
|
|
|
|
|
evaluate = long
|
|
|
default_value = 0L
|
|
|
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 traitlet."""
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
try:
|
|
|
return long(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class Float(TraitletType):
|
|
|
"""A float traitlet."""
|
|
|
|
|
|
evaluate = float
|
|
|
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 traitlet."""
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
try:
|
|
|
return float(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
class Complex(TraitletType):
|
|
|
"""A traitlet for complex numbers."""
|
|
|
|
|
|
evaluate = complex
|
|
|
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 traitlet."""
|
|
|
|
|
|
def validate (self, obj, value):
|
|
|
try:
|
|
|
return complex(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class Str(TraitletType):
|
|
|
"""A traitlet for strings."""
|
|
|
|
|
|
evaluate = lambda x: x
|
|
|
default_value = ''
|
|
|
info_text = 'a string'
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, str):
|
|
|
return value
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class CStr(Str):
|
|
|
"""A casting version of the string traitlet."""
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
try:
|
|
|
return str(value)
|
|
|
except:
|
|
|
try:
|
|
|
return unicode(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class Unicode(TraitletType):
|
|
|
"""A traitlet for unicode strings."""
|
|
|
|
|
|
evaluate = unicode
|
|
|
default_value = u''
|
|
|
info_text = 'a unicode string'
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if isinstance(value, unicode):
|
|
|
return value
|
|
|
if isinstance(value, str):
|
|
|
return unicode(value)
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class CUnicode(Unicode):
|
|
|
"""A casting version of the unicode traitlet."""
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
try:
|
|
|
return unicode(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class Bool(TraitletType):
|
|
|
"""A boolean (True, False) traitlet."""
|
|
|
evaluate = bool
|
|
|
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 traitlet."""
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
try:
|
|
|
return bool(value)
|
|
|
except:
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class Enum(TraitletType):
|
|
|
"""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
|
|
|
self._allow_none = allow_none
|
|
|
super(Enum, self).__init__(default_value, **metadata)
|
|
|
|
|
|
def validate(self, obj, value):
|
|
|
if value is None:
|
|
|
if self._allow_none:
|
|
|
return 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 value is None:
|
|
|
if self._allow_none:
|
|
|
return value
|
|
|
|
|
|
if not isinstance(value, str):
|
|
|
self.error(obj, value)
|
|
|
|
|
|
for v in self.values:
|
|
|
if v.lower() == value.lower():
|
|
|
return v
|
|
|
self.error(obj, value)
|
|
|
|
|
|
|
|
|
class List(Instance):
|
|
|
"""An instance of a Python list."""
|
|
|
|
|
|
def __init__(self, default_value=None, allow_none=True, **metadata):
|
|
|
"""Create a list traitlet type from a list or tuple.
|
|
|
|
|
|
The default value is created by doing ``list(default_value)``,
|
|
|
which creates a copy of the ``default_value``.
|
|
|
"""
|
|
|
if default_value is None:
|
|
|
args = ((),)
|
|
|
elif isinstance(default_value, SequenceTypes):
|
|
|
args = (default_value,)
|
|
|
|
|
|
super(List,self).__init__(klass=list, args=args,
|
|
|
allow_none=allow_none, **metadata)
|
|
|
|
