1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
|
#------------------------------------------------------------------------------
# Copyright (c) 2005, Enthought, Inc.
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in enthought/LICENSE.txt and may be redistributed only
# under the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
# Thanks for using Enthought open source!
#
# Author: Enthought, Inc.
# Description: <Enthought naming package component>
#------------------------------------------------------------------------------
""" A naming context for a Python namespace. """
# Enthought library imports.
from enthought.traits.api import Any, Dict, Instance, Property
# Local imports.
from address import Address
from binding import Binding
from context import Context
from naming_manager import naming_manager
from py_object_factory import PyObjectFactory
from reference import Reference
from referenceable import Referenceable
from referenceable_state_factory import ReferenceableStateFactory
# The default environment.
ENVIRONMENT = {
# 'Context' properties.
Context.OBJECT_FACTORIES : [PyObjectFactory()],
Context.STATE_FACTORIES : [ReferenceableStateFactory()],
}
class PyContext(Context, Referenceable):
""" A naming context for a Python namespace. """
#### 'Context' interface ##################################################
# The naming environment in effect for this context.
environment = Dict(ENVIRONMENT)
#### 'PyContext' interface ################################################
# The Python namespace that we represent.
namespace = Any
# If the namespace is actual a Python object that has a '__dict__'
# attribute, then this will be that object (the namespace will be the
# object's '__dict__'.
obj = Any
#### 'Referenceable' interface ############################################
# The object's reference suitable for binding in a naming context.
reference = Property(Instance(Reference))
###########################################################################
# 'object' interface.
###########################################################################
def __init__(self, **traits):
""" Creates a new context. """
# Base class constructor.
super(PyContext, self).__init__(**traits)
if type(self.namespace) is not dict:
if hasattr(self.namespace, '__dict__'):
self.obj = self.namespace
self.namespace = self.namespace.__dict__
else:
raise ValueError('Need a dictionary or a __dict__ attribute')
return
###########################################################################
# 'Referenceable' interface.
###########################################################################
#### Properties ###########################################################
def _get_reference(self):
""" Returns a reference to this object suitable for binding. """
reference = Reference(
class_name = self.__class__.__name__,
addresses = [Address(type='py_context', content=self.namespace)]
)
return reference
###########################################################################
# Protected 'Context' interface.
###########################################################################
def _is_bound(self, name):
""" Is a name bound in this context? """
return self.namespace.has_key(name)
def _lookup(self, name):
""" Looks up a name in this context. """
obj = self.namespace[name]
return naming_manager.get_object_instance(obj, name, self)
def _bind(self, name, obj):
""" Binds a name to an object in this context. """
state = naming_manager.get_state_to_bind(obj, name,self)
self.namespace[name] = state
# Trait event notification.
# An "added" event is fired by the bind method of the base calss (which calls
# this one), so we don't need to do the changed here (which would be the wrong
# thing anyway) -- LGV
#
# self.trait_property_changed('context_changed', None, None)
return
def _rebind(self, name, obj):
""" Rebinds a name to a object in this context. """
self._bind(name, obj)
return
def _unbind(self, name):
""" Unbinds a name from this context. """
del self.namespace[name]
# Trait event notification.
self.trait_property_changed('context_changed', None, None)
return
def _rename(self, old_name, new_name):
""" Renames an object in this context. """
state = self.namespace[old_name]
# Bind the new name.
self.namespace[new_name] = state
# Unbind the old one.
del self.namespace[old_name]
# Trait event notification.
self.context_changed = True
return
def _create_subcontext(self, name):
""" Creates a sub-context of this context. """
sub = self._context_factory(name, {})
self.namespace[name] = sub
# Trait event notification.
self.trait_property_changed('context_changed', None, None)
return sub
def _destroy_subcontext(self, name):
""" Destroys a sub-context of this context. """
del self.namespace[name]
# Trait event notification.
self.trait_property_changed('context_changed', None, None)
return
def _list_bindings(self):
""" Lists the bindings in this context. """
bindings = []
for name, value in self.namespace.items():
bindings.append(Binding(name=name, obj=self._lookup(name),
context=self))
return bindings
def _list_names(self):
""" Lists the names bound in this context. """
return self.namespace.keys()
###########################################################################
# Private interface.
###########################################################################
def _context_factory(self, name, namespace):
""" Create a sub-context. """
return self.__class__(namespace=namespace)
#### EOF ######################################################################
|
