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@@ -1,1358 +1,1355 b'' | |||
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1 | 1 | #!/usr/bin/env python |
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2 | 2 | # encoding: utf-8 |
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3 | 3 | """ |
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4 | 4 | A lightweight Traits like module. |
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5 | 5 | |
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6 | 6 | This is designed to provide a lightweight, simple, pure Python version of |
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7 | 7 | many of the capabilities of enthought.traits. This includes: |
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8 | 8 | |
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9 | 9 | * Validation |
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10 | 10 | * Type specification with defaults |
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11 | 11 | * Static and dynamic notification |
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12 | 12 | * Basic predefined types |
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13 | 13 | * An API that is similar to enthought.traits |
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14 | 14 | |
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15 | 15 | We don't support: |
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16 | 16 | |
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17 | 17 | * Delegation |
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18 | 18 | * Automatic GUI generation |
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19 | 19 | * A full set of trait types. Most importantly, we don't provide container |
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20 | 20 | traits (list, dict, tuple) that can trigger notifications if their |
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21 | 21 | contents change. |
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22 | 22 | * API compatibility with enthought.traits |
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23 | 23 | |
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24 | 24 | There are also some important difference in our design: |
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25 | 25 | |
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26 | 26 | * enthought.traits does not validate default values. We do. |
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27 | 27 | |
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28 | 28 | We choose to create this module because we need these capabilities, but |
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29 | 29 | we need them to be pure Python so they work in all Python implementations, |
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30 | 30 | including Jython and IronPython. |
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31 | 31 | |
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32 | 32 | Authors: |
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33 | 33 | |
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34 | 34 | * Brian Granger |
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35 | 35 | * Enthought, Inc. Some of the code in this file comes from enthought.traits |
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36 | 36 | and is licensed under the BSD license. Also, many of the ideas also come |
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37 | 37 | from enthought.traits even though our implementation is very different. |
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38 | 38 | """ |
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39 | 39 | |
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40 | 40 | #----------------------------------------------------------------------------- |
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41 | 41 | # Copyright (C) 2008-2009 The IPython Development Team |
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42 | 42 | # |
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43 | 43 | # Distributed under the terms of the BSD License. The full license is in |
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44 | 44 | # the file COPYING, distributed as part of this software. |
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45 | 45 | #----------------------------------------------------------------------------- |
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46 | 46 | |
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47 | 47 | #----------------------------------------------------------------------------- |
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48 | 48 | # Imports |
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49 | 49 | #----------------------------------------------------------------------------- |
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50 | 50 | |
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51 | 51 | |
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52 | 52 | import inspect |
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53 | 53 | import sys |
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54 | 54 | import types |
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55 | 55 | from types import ( |
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56 | 56 | InstanceType, ClassType, FunctionType, |
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57 | 57 | ListType, TupleType |
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58 | 58 | ) |
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59 | 59 | from .importstring import import_item |
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60 | 60 | |
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61 | 61 | ClassTypes = (ClassType, type) |
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62 | 62 | |
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63 | 63 | SequenceTypes = (ListType, TupleType, set, frozenset) |
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64 | 64 | |
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65 | 65 | #----------------------------------------------------------------------------- |
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66 | 66 | # Basic classes |
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67 | 67 | #----------------------------------------------------------------------------- |
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68 | 68 | |
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69 | 69 | |
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70 | 70 | class NoDefaultSpecified ( object ): pass |
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71 | 71 | NoDefaultSpecified = NoDefaultSpecified() |
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72 | 72 | |
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73 | 73 | |
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74 | 74 | class Undefined ( object ): pass |
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75 | 75 | Undefined = Undefined() |
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76 | 76 | |
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77 | 77 | class TraitError(Exception): |
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78 | 78 | pass |
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79 | 79 | |
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80 | 80 | #----------------------------------------------------------------------------- |
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81 | 81 | # Utilities |
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82 | 82 | #----------------------------------------------------------------------------- |
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83 | 83 | |
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84 | 84 | |
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85 | 85 | def class_of ( object ): |
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86 | 86 | """ Returns a string containing the class name of an object with the |
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87 | 87 | correct indefinite article ('a' or 'an') preceding it (e.g., 'an Image', |
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88 | 88 | 'a PlotValue'). |
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89 | 89 | """ |
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90 | 90 | if isinstance( object, basestring ): |
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91 | 91 | return add_article( object ) |
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92 | 92 | |
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93 | 93 | return add_article( object.__class__.__name__ ) |
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94 | 94 | |
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95 | 95 | |
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96 | 96 | def add_article ( name ): |
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97 | 97 | """ Returns a string containing the correct indefinite article ('a' or 'an') |
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98 | 98 | prefixed to the specified string. |
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99 | 99 | """ |
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100 | 100 | if name[:1].lower() in 'aeiou': |
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101 | 101 | return 'an ' + name |
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102 | 102 | |
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103 | 103 | return 'a ' + name |
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104 | 104 | |
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105 | 105 | |
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106 | 106 | def repr_type(obj): |
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107 | 107 | """ Return a string representation of a value and its type for readable |
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108 | 108 | error messages. |
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109 | 109 | """ |
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110 | 110 | the_type = type(obj) |
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111 | 111 | if the_type is InstanceType: |
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112 | 112 | # Old-style class. |
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113 | 113 | the_type = obj.__class__ |
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114 | 114 | msg = '%r %r' % (obj, the_type) |
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115 | 115 | return msg |
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116 | 116 | |
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117 | 117 | |
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118 | 118 | def parse_notifier_name(name): |
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119 | 119 | """Convert the name argument to a list of names. |
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120 | 120 | |
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121 | 121 | Examples |
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122 | 122 | -------- |
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123 | 123 | |
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124 | 124 | >>> parse_notifier_name('a') |
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125 | 125 | ['a'] |
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126 | 126 | >>> parse_notifier_name(['a','b']) |
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127 | 127 | ['a', 'b'] |
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128 | 128 | >>> parse_notifier_name(None) |
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129 | 129 | ['anytrait'] |
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130 | 130 | """ |
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131 | 131 | if isinstance(name, str): |
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132 | 132 | return [name] |
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133 | 133 | elif name is None: |
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134 | 134 | return ['anytrait'] |
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135 | 135 | elif isinstance(name, (list, tuple)): |
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136 | 136 | for n in name: |
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137 | 137 | assert isinstance(n, str), "names must be strings" |
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138 | 138 | return name |
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139 | 139 | |
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140 | 140 | |
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141 | 141 | class _SimpleTest: |
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142 | 142 | def __init__ ( self, value ): self.value = value |
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143 | 143 | def __call__ ( self, test ): |
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144 | 144 | return test == self.value |
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145 | 145 | def __repr__(self): |
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146 | 146 | return "<SimpleTest(%r)" % self.value |
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147 | 147 | def __str__(self): |
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148 | 148 | return self.__repr__() |
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149 | 149 | |
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150 | 150 | |
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151 | 151 | def getmembers(object, predicate=None): |
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152 | 152 | """A safe version of inspect.getmembers that handles missing attributes. |
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153 | 153 | |
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154 | 154 | This is useful when there are descriptor based attributes that for |
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155 | 155 | some reason raise AttributeError even though they exist. This happens |
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156 | 156 | in zope.inteface with the __provides__ attribute. |
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157 | 157 | """ |
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158 | 158 | results = [] |
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159 | 159 | for key in dir(object): |
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160 | 160 | try: |
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161 | 161 | value = getattr(object, key) |
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162 | 162 | except AttributeError: |
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163 | 163 | pass |
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164 | 164 | else: |
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165 | 165 | if not predicate or predicate(value): |
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166 | 166 | results.append((key, value)) |
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167 | 167 | results.sort() |
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168 | 168 | return results |
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169 | 169 | |
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170 | 170 | |
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171 | 171 | #----------------------------------------------------------------------------- |
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172 | 172 | # Base TraitType for all traits |
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173 | 173 | #----------------------------------------------------------------------------- |
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174 | 174 | |
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175 | 175 | |
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176 | 176 | class TraitType(object): |
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177 | 177 | """A base class for all trait descriptors. |
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178 | 178 | |
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179 | 179 | Notes |
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180 | 180 | ----- |
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181 | 181 | Our implementation of traits is based on Python's descriptor |
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182 | 182 | prototol. This class is the base class for all such descriptors. The |
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183 | 183 | only magic we use is a custom metaclass for the main :class:`HasTraits` |
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184 | 184 | class that does the following: |
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185 | 185 | |
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186 | 186 | 1. Sets the :attr:`name` attribute of every :class:`TraitType` |
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187 | 187 | instance in the class dict to the name of the attribute. |
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188 | 188 | 2. Sets the :attr:`this_class` attribute of every :class:`TraitType` |
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189 | 189 | instance in the class dict to the *class* that declared the trait. |
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190 | 190 | This is used by the :class:`This` trait to allow subclasses to |
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191 | 191 | accept superclasses for :class:`This` values. |
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192 | 192 | """ |
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193 | 193 | |
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194 | 194 | |
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195 | 195 | metadata = {} |
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196 | 196 | default_value = Undefined |
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197 | 197 | info_text = 'any value' |
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198 | 198 | |
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199 | 199 | def __init__(self, default_value=NoDefaultSpecified, **metadata): |
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200 | 200 | """Create a TraitType. |
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201 | 201 | """ |
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202 | 202 | if default_value is not NoDefaultSpecified: |
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203 | 203 | self.default_value = default_value |
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204 | 204 | |
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205 | 205 | if len(metadata) > 0: |
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206 | 206 | if len(self.metadata) > 0: |
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207 | 207 | self._metadata = self.metadata.copy() |
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208 | 208 | self._metadata.update(metadata) |
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209 | 209 | else: |
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210 | 210 | self._metadata = metadata |
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211 | 211 | else: |
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212 | 212 | self._metadata = self.metadata |
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213 | 213 | |
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214 | 214 | self.init() |
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215 | 215 | |
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216 | 216 | def init(self): |
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217 | 217 | pass |
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218 | 218 | |
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219 | 219 | def get_default_value(self): |
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220 | 220 | """Create a new instance of the default value.""" |
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221 | 221 | return self.default_value |
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222 | 222 | |
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223 | 223 | def instance_init(self, obj): |
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224 | 224 | """This is called by :meth:`HasTraits.__new__` to finish init'ing. |
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225 | 225 | |
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226 | 226 | Some stages of initialization must be delayed until the parent |
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227 | 227 | :class:`HasTraits` instance has been created. This method is |
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228 | 228 | called in :meth:`HasTraits.__new__` after the instance has been |
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229 | 229 | created. |
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230 | 230 | |
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231 | 231 | This method trigger the creation and validation of default values |
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232 | 232 | and also things like the resolution of str given class names in |
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233 | 233 | :class:`Type` and :class`Instance`. |
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234 | 234 | |
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235 | 235 | Parameters |
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236 | 236 | ---------- |
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237 | 237 | obj : :class:`HasTraits` instance |
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238 | 238 | The parent :class:`HasTraits` instance that has just been |
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239 | 239 | created. |
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240 | 240 | """ |
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241 | 241 | self.set_default_value(obj) |
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242 | 242 | |
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243 | 243 | def set_default_value(self, obj): |
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244 | 244 | """Set the default value on a per instance basis. |
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245 | 245 | |
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246 | 246 | This method is called by :meth:`instance_init` to create and |
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247 | 247 | validate the default value. The creation and validation of |
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248 | 248 | default values must be delayed until the parent :class:`HasTraits` |
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249 | 249 | class has been instantiated. |
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250 | 250 | """ |
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251 | 251 | # Check for a deferred initializer defined in the same class as the |
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252 | 252 | # trait declaration or above. |
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253 | 253 | mro = type(obj).mro() |
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254 | 254 | meth_name = '_%s_default' % self.name |
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255 | 255 | for cls in mro[:mro.index(self.this_class)+1]: |
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256 | 256 | if meth_name in cls.__dict__: |
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257 | 257 | break |
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258 | 258 | else: |
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259 | 259 | # We didn't find one. Do static initialization. |
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260 | 260 | dv = self.get_default_value() |
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261 | 261 | newdv = self._validate(obj, dv) |
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262 | 262 | obj._trait_values[self.name] = newdv |
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263 | 263 | return |
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264 | 264 | # Complete the dynamic initialization. |
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265 | 265 | obj._trait_dyn_inits[self.name] = cls.__dict__[meth_name] |
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266 | 266 | |
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267 | 267 | def __get__(self, obj, cls=None): |
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268 | 268 | """Get the value of the trait by self.name for the instance. |
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269 | 269 | |
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270 | 270 | Default values are instantiated when :meth:`HasTraits.__new__` |
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271 | 271 | is called. Thus by the time this method gets called either the |
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272 | 272 | default value or a user defined value (they called :meth:`__set__`) |
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273 | 273 | is in the :class:`HasTraits` instance. |
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274 | 274 | """ |
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275 | 275 | if obj is None: |
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276 | 276 | return self |
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277 | 277 | else: |
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278 | 278 | try: |
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279 | 279 | value = obj._trait_values[self.name] |
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280 | 280 | except KeyError: |
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281 | 281 | # Check for a dynamic initializer. |
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282 | 282 | if self.name in obj._trait_dyn_inits: |
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283 | 283 | value = obj._trait_dyn_inits[self.name](obj) |
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284 | 284 | # FIXME: Do we really validate here? |
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285 | 285 | value = self._validate(obj, value) |
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286 | 286 | obj._trait_values[self.name] = value |
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287 | 287 | return value |
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288 | 288 | else: |
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289 | 289 | raise TraitError('Unexpected error in TraitType: ' |
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290 | 290 | 'both default value and dynamic initializer are ' |
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291 | 291 | 'absent.') |
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292 | 292 | except Exception: |
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293 | 293 | # HasTraits should call set_default_value to populate |
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294 | 294 | # this. So this should never be reached. |
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295 | 295 | raise TraitError('Unexpected error in TraitType: ' |
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296 | 296 | 'default value not set properly') |
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297 | 297 | else: |
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298 | 298 | return value |
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299 | 299 | |
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300 | 300 | def __set__(self, obj, value): |
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301 | 301 | new_value = self._validate(obj, value) |
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302 | 302 | old_value = self.__get__(obj) |
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303 | 303 | if old_value != new_value: |
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304 | 304 | obj._trait_values[self.name] = new_value |
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305 | 305 | obj._notify_trait(self.name, old_value, new_value) |
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306 | 306 | |
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307 | 307 | def _validate(self, obj, value): |
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308 | 308 | if hasattr(self, 'validate'): |
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309 | 309 | return self.validate(obj, value) |
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310 | 310 | elif hasattr(self, 'is_valid_for'): |
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311 | 311 | valid = self.is_valid_for(value) |
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312 | 312 | if valid: |
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313 | 313 | return value |
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314 | 314 | else: |
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315 | 315 | raise TraitError('invalid value for type: %r' % value) |
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316 | 316 | elif hasattr(self, 'value_for'): |
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317 | 317 | return self.value_for(value) |
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318 | 318 | else: |
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319 | 319 | return value |
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320 | 320 | |
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321 | 321 | def info(self): |
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322 | 322 | return self.info_text |
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323 | 323 | |
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324 | 324 | def error(self, obj, value): |
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325 | 325 | if obj is not None: |
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326 | 326 | e = "The '%s' trait of %s instance must be %s, but a value of %s was specified." \ |
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327 | 327 | % (self.name, class_of(obj), |
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328 | 328 | self.info(), repr_type(value)) |
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329 | 329 | else: |
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330 | 330 | e = "The '%s' trait must be %s, but a value of %r was specified." \ |
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331 | 331 | % (self.name, self.info(), repr_type(value)) |
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332 | 332 | raise TraitError(e) |
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333 | 333 | |
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334 | 334 | def get_metadata(self, key): |
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335 | 335 | return getattr(self, '_metadata', {}).get(key, None) |
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336 | 336 | |
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337 | 337 | def set_metadata(self, key, value): |
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338 | 338 | getattr(self, '_metadata', {})[key] = value |
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339 | 339 | |
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340 | 340 | |
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341 | 341 | #----------------------------------------------------------------------------- |
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342 | 342 | # The HasTraits implementation |
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343 | 343 | #----------------------------------------------------------------------------- |
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344 | 344 | |
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345 | 345 | |
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346 | 346 | class MetaHasTraits(type): |
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347 | 347 | """A metaclass for HasTraits. |
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348 | 348 | |
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349 | 349 | This metaclass makes sure that any TraitType class attributes are |
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350 | 350 | instantiated and sets their name attribute. |
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351 | 351 | """ |
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352 | 352 | |
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353 | 353 | def __new__(mcls, name, bases, classdict): |
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354 | 354 | """Create the HasTraits class. |
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355 | 355 | |
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356 | 356 | This instantiates all TraitTypes in the class dict and sets their |
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357 | 357 | :attr:`name` attribute. |
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358 | 358 | """ |
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359 | 359 | # print "MetaHasTraitlets (mcls, name): ", mcls, name |
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360 | 360 | # print "MetaHasTraitlets (bases): ", bases |
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361 | 361 | # print "MetaHasTraitlets (classdict): ", classdict |
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362 | 362 | for k,v in classdict.iteritems(): |
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363 | 363 | if isinstance(v, TraitType): |
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364 | 364 | v.name = k |
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365 | 365 | elif inspect.isclass(v): |
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366 | 366 | if issubclass(v, TraitType): |
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367 | 367 | vinst = v() |
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368 | 368 | vinst.name = k |
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369 | 369 | classdict[k] = vinst |
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370 | 370 | return super(MetaHasTraits, mcls).__new__(mcls, name, bases, classdict) |
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371 | 371 | |
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372 | 372 | def __init__(cls, name, bases, classdict): |
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373 | 373 | """Finish initializing the HasTraits class. |
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374 | 374 | |
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375 | 375 | This sets the :attr:`this_class` attribute of each TraitType in the |
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376 | 376 | class dict to the newly created class ``cls``. |
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377 | 377 | """ |
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378 | 378 | for k, v in classdict.iteritems(): |
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379 | 379 | if isinstance(v, TraitType): |
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380 | 380 | v.this_class = cls |
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381 | 381 | super(MetaHasTraits, cls).__init__(name, bases, classdict) |
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382 | 382 | |
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383 | 383 | class HasTraits(object): |
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384 | 384 | |
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385 | 385 | __metaclass__ = MetaHasTraits |
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386 | 386 | |
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387 | 387 | def __new__(cls, **kw): |
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388 | 388 | # This is needed because in Python 2.6 object.__new__ only accepts |
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389 | 389 | # the cls argument. |
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390 | 390 | new_meth = super(HasTraits, cls).__new__ |
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391 | 391 | if new_meth is object.__new__: |
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392 | 392 | inst = new_meth(cls) |
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393 | 393 | else: |
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394 | 394 | inst = new_meth(cls, **kw) |
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395 | 395 | inst._trait_values = {} |
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396 | 396 | inst._trait_notifiers = {} |
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397 | 397 | inst._trait_dyn_inits = {} |
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398 | 398 | # Here we tell all the TraitType instances to set their default |
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399 | 399 | # values on the instance. |
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400 | 400 | for key in dir(cls): |
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401 | 401 | # Some descriptors raise AttributeError like zope.interface's |
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402 | 402 | # __provides__ attributes even though they exist. This causes |
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403 | 403 | # AttributeErrors even though they are listed in dir(cls). |
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404 | 404 | try: |
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405 | 405 | value = getattr(cls, key) |
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406 | 406 | except AttributeError: |
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407 | 407 | pass |
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408 | 408 | else: |
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409 | 409 | if isinstance(value, TraitType): |
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410 | 410 | value.instance_init(inst) |
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411 | 411 | |
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412 | 412 | return inst |
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413 | 413 | |
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414 | 414 | def __init__(self, **kw): |
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415 | 415 | # Allow trait values to be set using keyword arguments. |
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416 | 416 | # We need to use setattr for this to trigger validation and |
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417 | 417 | # notifications. |
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418 | 418 | for key, value in kw.iteritems(): |
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419 | 419 | setattr(self, key, value) |
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420 | 420 | |
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421 | 421 | def _notify_trait(self, name, old_value, new_value): |
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422 | 422 | |
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423 | 423 | # First dynamic ones |
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424 | 424 | callables = self._trait_notifiers.get(name,[]) |
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425 | 425 | more_callables = self._trait_notifiers.get('anytrait',[]) |
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426 | 426 | callables.extend(more_callables) |
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427 | 427 | |
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428 | 428 | # Now static ones |
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429 | 429 | try: |
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430 | 430 | cb = getattr(self, '_%s_changed' % name) |
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431 | 431 | except: |
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432 | 432 | pass |
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433 | 433 | else: |
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434 | 434 | callables.append(cb) |
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435 | 435 | |
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436 | 436 | # Call them all now |
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437 | 437 | for c in callables: |
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438 | 438 | # Traits catches and logs errors here. I allow them to raise |
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439 | 439 | if callable(c): |
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440 | 440 | argspec = inspect.getargspec(c) |
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441 | 441 | nargs = len(argspec[0]) |
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442 | 442 | # Bound methods have an additional 'self' argument |
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443 | 443 | # I don't know how to treat unbound methods, but they |
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444 | 444 | # can't really be used for callbacks. |
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445 | 445 | if isinstance(c, types.MethodType): |
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446 | 446 | offset = -1 |
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447 | 447 | else: |
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448 | 448 | offset = 0 |
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449 | 449 | if nargs + offset == 0: |
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450 | 450 | c() |
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451 | 451 | elif nargs + offset == 1: |
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452 | 452 | c(name) |
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453 | 453 | elif nargs + offset == 2: |
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454 | 454 | c(name, new_value) |
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455 | 455 | elif nargs + offset == 3: |
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456 | 456 | c(name, old_value, new_value) |
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457 | 457 | else: |
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458 | 458 | raise TraitError('a trait changed callback ' |
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459 | 459 | 'must have 0-3 arguments.') |
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460 | 460 | else: |
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461 | 461 | raise TraitError('a trait changed callback ' |
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462 | 462 | 'must be callable.') |
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463 | 463 | |
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464 | 464 | |
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465 | 465 | def _add_notifiers(self, handler, name): |
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466 | 466 | if not self._trait_notifiers.has_key(name): |
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467 | 467 | nlist = [] |
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468 | 468 | self._trait_notifiers[name] = nlist |
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469 | 469 | else: |
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470 | 470 | nlist = self._trait_notifiers[name] |
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471 | 471 | if handler not in nlist: |
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472 | 472 | nlist.append(handler) |
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473 | 473 | |
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474 | 474 | def _remove_notifiers(self, handler, name): |
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475 | 475 | if self._trait_notifiers.has_key(name): |
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476 | 476 | nlist = self._trait_notifiers[name] |
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477 | 477 | try: |
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478 | 478 | index = nlist.index(handler) |
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479 | 479 | except ValueError: |
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480 | 480 | pass |
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481 | 481 | else: |
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482 | 482 | del nlist[index] |
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483 | 483 | |
|
484 | 484 | def on_trait_change(self, handler, name=None, remove=False): |
|
485 | 485 | """Setup a handler to be called when a trait changes. |
|
486 | 486 | |
|
487 | 487 | This is used to setup dynamic notifications of trait changes. |
|
488 | 488 | |
|
489 | 489 | Static handlers can be created by creating methods on a HasTraits |
|
490 | 490 | subclass with the naming convention '_[traitname]_changed'. Thus, |
|
491 | 491 | to create static handler for the trait 'a', create the method |
|
492 | 492 | _a_changed(self, name, old, new) (fewer arguments can be used, see |
|
493 | 493 | below). |
|
494 | 494 | |
|
495 | 495 | Parameters |
|
496 | 496 | ---------- |
|
497 | 497 | handler : callable |
|
498 | 498 | A callable that is called when a trait changes. Its |
|
499 | 499 | signature can be handler(), handler(name), handler(name, new) |
|
500 | 500 | or handler(name, old, new). |
|
501 | 501 | name : list, str, None |
|
502 | 502 | If None, the handler will apply to all traits. If a list |
|
503 | 503 | of str, handler will apply to all names in the list. If a |
|
504 | 504 | str, the handler will apply just to that name. |
|
505 | 505 | remove : bool |
|
506 | 506 | If False (the default), then install the handler. If True |
|
507 | 507 | then unintall it. |
|
508 | 508 | """ |
|
509 | 509 | if remove: |
|
510 | 510 | names = parse_notifier_name(name) |
|
511 | 511 | for n in names: |
|
512 | 512 | self._remove_notifiers(handler, n) |
|
513 | 513 | else: |
|
514 | 514 | names = parse_notifier_name(name) |
|
515 | 515 | for n in names: |
|
516 | 516 | self._add_notifiers(handler, n) |
|
517 | 517 | |
|
518 | 518 | @classmethod |
|
519 | 519 | def class_trait_names(cls, **metadata): |
|
520 | 520 | """Get a list of all the names of this classes traits. |
|
521 | 521 | |
|
522 | 522 | This method is just like the :meth:`trait_names` method, but is unbound. |
|
523 | 523 | """ |
|
524 | 524 | return cls.class_traits(**metadata).keys() |
|
525 | 525 | |
|
526 | 526 | @classmethod |
|
527 | 527 | def class_traits(cls, **metadata): |
|
528 | 528 | """Get a list of all the traits of this class. |
|
529 | 529 | |
|
530 | 530 | This method is just like the :meth:`traits` method, but is unbound. |
|
531 | 531 | |
|
532 | 532 | The TraitTypes returned don't know anything about the values |
|
533 | 533 | that the various HasTrait's instances are holding. |
|
534 | 534 | |
|
535 | 535 | This follows the same algorithm as traits does and does not allow |
|
536 | 536 | for any simple way of specifying merely that a metadata name |
|
537 | 537 | exists, but has any value. This is because get_metadata returns |
|
538 | 538 | None if a metadata key doesn't exist. |
|
539 | 539 | """ |
|
540 | 540 | traits = dict([memb for memb in getmembers(cls) if \ |
|
541 | 541 | isinstance(memb[1], TraitType)]) |
|
542 | 542 | |
|
543 | 543 | if len(metadata) == 0: |
|
544 | 544 | return traits |
|
545 | 545 | |
|
546 | 546 | for meta_name, meta_eval in metadata.items(): |
|
547 | 547 | if type(meta_eval) is not FunctionType: |
|
548 | 548 | metadata[meta_name] = _SimpleTest(meta_eval) |
|
549 | 549 | |
|
550 | 550 | result = {} |
|
551 | 551 | for name, trait in traits.items(): |
|
552 | 552 | for meta_name, meta_eval in metadata.items(): |
|
553 | 553 | if not meta_eval(trait.get_metadata(meta_name)): |
|
554 | 554 | break |
|
555 | 555 | else: |
|
556 | 556 | result[name] = trait |
|
557 | 557 | |
|
558 | 558 | return result |
|
559 | 559 | |
|
560 | 560 | def trait_names(self, **metadata): |
|
561 | 561 | """Get a list of all the names of this classes traits.""" |
|
562 | 562 | return self.traits(**metadata).keys() |
|
563 | 563 | |
|
564 | 564 | def traits(self, **metadata): |
|
565 | 565 | """Get a list of all the traits of this class. |
|
566 | 566 | |
|
567 | 567 | The TraitTypes returned don't know anything about the values |
|
568 | 568 | that the various HasTrait's instances are holding. |
|
569 | 569 | |
|
570 | 570 | This follows the same algorithm as traits does and does not allow |
|
571 | 571 | for any simple way of specifying merely that a metadata name |
|
572 | 572 | exists, but has any value. This is because get_metadata returns |
|
573 | 573 | None if a metadata key doesn't exist. |
|
574 | 574 | """ |
|
575 | 575 | traits = dict([memb for memb in getmembers(self.__class__) if \ |
|
576 | 576 | isinstance(memb[1], TraitType)]) |
|
577 | 577 | |
|
578 | 578 | if len(metadata) == 0: |
|
579 | 579 | return traits |
|
580 | 580 | |
|
581 | 581 | for meta_name, meta_eval in metadata.items(): |
|
582 | 582 | if type(meta_eval) is not FunctionType: |
|
583 | 583 | metadata[meta_name] = _SimpleTest(meta_eval) |
|
584 | 584 | |
|
585 | 585 | result = {} |
|
586 | 586 | for name, trait in traits.items(): |
|
587 | 587 | for meta_name, meta_eval in metadata.items(): |
|
588 | 588 | if not meta_eval(trait.get_metadata(meta_name)): |
|
589 | 589 | break |
|
590 | 590 | else: |
|
591 | 591 | result[name] = trait |
|
592 | 592 | |
|
593 | 593 | return result |
|
594 | 594 | |
|
595 | 595 | def trait_metadata(self, traitname, key): |
|
596 | 596 | """Get metadata values for trait by key.""" |
|
597 | 597 | try: |
|
598 | 598 | trait = getattr(self.__class__, traitname) |
|
599 | 599 | except AttributeError: |
|
600 | 600 | raise TraitError("Class %s does not have a trait named %s" % |
|
601 | 601 | (self.__class__.__name__, traitname)) |
|
602 | 602 | else: |
|
603 | 603 | return trait.get_metadata(key) |
|
604 | 604 | |
|
605 | 605 | #----------------------------------------------------------------------------- |
|
606 | 606 | # Actual TraitTypes implementations/subclasses |
|
607 | 607 | #----------------------------------------------------------------------------- |
|
608 | 608 | |
|
609 | 609 | #----------------------------------------------------------------------------- |
|
610 | 610 | # TraitTypes subclasses for handling classes and instances of classes |
|
611 | 611 | #----------------------------------------------------------------------------- |
|
612 | 612 | |
|
613 | 613 | |
|
614 | 614 | class ClassBasedTraitType(TraitType): |
|
615 | 615 | """A trait with error reporting for Type, Instance and This.""" |
|
616 | 616 | |
|
617 | 617 | def error(self, obj, value): |
|
618 | 618 | kind = type(value) |
|
619 | 619 | if kind is InstanceType: |
|
620 | 620 | msg = 'class %s' % value.__class__.__name__ |
|
621 | 621 | else: |
|
622 | 622 | msg = '%s (i.e. %s)' % ( str( kind )[1:-1], repr( value ) ) |
|
623 | 623 | |
|
624 | 624 | if obj is not None: |
|
625 | 625 | e = "The '%s' trait of %s instance must be %s, but a value of %s was specified." \ |
|
626 | 626 | % (self.name, class_of(obj), |
|
627 | 627 | self.info(), msg) |
|
628 | 628 | else: |
|
629 | 629 | e = "The '%s' trait must be %s, but a value of %r was specified." \ |
|
630 | 630 | % (self.name, self.info(), msg) |
|
631 | 631 | |
|
632 | 632 | raise TraitError(e) |
|
633 | 633 | |
|
634 | 634 | |
|
635 | 635 | class Type(ClassBasedTraitType): |
|
636 | 636 | """A trait whose value must be a subclass of a specified class.""" |
|
637 | 637 | |
|
638 | 638 | def __init__ (self, default_value=None, klass=None, allow_none=True, **metadata ): |
|
639 | 639 | """Construct a Type trait |
|
640 | 640 | |
|
641 | 641 | A Type trait specifies that its values must be subclasses of |
|
642 | 642 | a particular class. |
|
643 | 643 | |
|
644 | 644 | If only ``default_value`` is given, it is used for the ``klass`` as |
|
645 | 645 | well. |
|
646 | 646 | |
|
647 | 647 | Parameters |
|
648 | 648 | ---------- |
|
649 | 649 | default_value : class, str or None |
|
650 | 650 | The default value must be a subclass of klass. If an str, |
|
651 | 651 | the str must be a fully specified class name, like 'foo.bar.Bah'. |
|
652 | 652 | The string is resolved into real class, when the parent |
|
653 | 653 | :class:`HasTraits` class is instantiated. |
|
654 | 654 | klass : class, str, None |
|
655 | 655 | Values of this trait must be a subclass of klass. The klass |
|
656 | 656 | may be specified in a string like: 'foo.bar.MyClass'. |
|
657 | 657 | The string is resolved into real class, when the parent |
|
658 | 658 | :class:`HasTraits` class is instantiated. |
|
659 | 659 | allow_none : boolean |
|
660 | 660 | Indicates whether None is allowed as an assignable value. Even if |
|
661 | 661 | ``False``, the default value may be ``None``. |
|
662 | 662 | """ |
|
663 | 663 | if default_value is None: |
|
664 | 664 | if klass is None: |
|
665 | 665 | klass = object |
|
666 | 666 | elif klass is None: |
|
667 | 667 | klass = default_value |
|
668 | 668 | |
|
669 | 669 | if not (inspect.isclass(klass) or isinstance(klass, basestring)): |
|
670 | 670 | raise TraitError("A Type trait must specify a class.") |
|
671 | 671 | |
|
672 | 672 | self.klass = klass |
|
673 | 673 | self._allow_none = allow_none |
|
674 | 674 | |
|
675 | 675 | super(Type, self).__init__(default_value, **metadata) |
|
676 | 676 | |
|
677 | 677 | def validate(self, obj, value): |
|
678 | 678 | """Validates that the value is a valid object instance.""" |
|
679 | 679 | try: |
|
680 | 680 | if issubclass(value, self.klass): |
|
681 | 681 | return value |
|
682 | 682 | except: |
|
683 | 683 | if (value is None) and (self._allow_none): |
|
684 | 684 | return value |
|
685 | 685 | |
|
686 | 686 | self.error(obj, value) |
|
687 | 687 | |
|
688 | 688 | def info(self): |
|
689 | 689 | """ Returns a description of the trait.""" |
|
690 | 690 | if isinstance(self.klass, basestring): |
|
691 | 691 | klass = self.klass |
|
692 | 692 | else: |
|
693 | 693 | klass = self.klass.__name__ |
|
694 | 694 | result = 'a subclass of ' + klass |
|
695 | 695 | if self._allow_none: |
|
696 | 696 | return result + ' or None' |
|
697 | 697 | return result |
|
698 | 698 | |
|
699 | 699 | def instance_init(self, obj): |
|
700 | 700 | self._resolve_classes() |
|
701 | 701 | super(Type, self).instance_init(obj) |
|
702 | 702 | |
|
703 | 703 | def _resolve_classes(self): |
|
704 | 704 | if isinstance(self.klass, basestring): |
|
705 | 705 | self.klass = import_item(self.klass) |
|
706 | 706 | if isinstance(self.default_value, basestring): |
|
707 | 707 | self.default_value = import_item(self.default_value) |
|
708 | 708 | |
|
709 | 709 | def get_default_value(self): |
|
710 | 710 | return self.default_value |
|
711 | 711 | |
|
712 | 712 | |
|
713 | 713 | class DefaultValueGenerator(object): |
|
714 | 714 | """A class for generating new default value instances.""" |
|
715 | 715 | |
|
716 | 716 | def __init__(self, *args, **kw): |
|
717 | 717 | self.args = args |
|
718 | 718 | self.kw = kw |
|
719 | 719 | |
|
720 | 720 | def generate(self, klass): |
|
721 | 721 | return klass(*self.args, **self.kw) |
|
722 | 722 | |
|
723 | 723 | |
|
724 | 724 | class Instance(ClassBasedTraitType): |
|
725 | 725 | """A trait whose value must be an instance of a specified class. |
|
726 | 726 | |
|
727 | 727 | The value can also be an instance of a subclass of the specified class. |
|
728 | 728 | """ |
|
729 | 729 | |
|
730 | 730 | def __init__(self, klass=None, args=None, kw=None, |
|
731 | 731 | allow_none=True, **metadata ): |
|
732 | 732 | """Construct an Instance trait. |
|
733 | 733 | |
|
734 | 734 | This trait allows values that are instances of a particular |
|
735 | 735 | class or its sublclasses. Our implementation is quite different |
|
736 | 736 | from that of enthough.traits as we don't allow instances to be used |
|
737 | 737 | for klass and we handle the ``args`` and ``kw`` arguments differently. |
|
738 | 738 | |
|
739 | 739 | Parameters |
|
740 | 740 | ---------- |
|
741 | 741 | klass : class, str |
|
742 | 742 | The class that forms the basis for the trait. Class names |
|
743 | 743 | can also be specified as strings, like 'foo.bar.Bar'. |
|
744 | 744 | args : tuple |
|
745 | 745 | Positional arguments for generating the default value. |
|
746 | 746 | kw : dict |
|
747 | 747 | Keyword arguments for generating the default value. |
|
748 | 748 | allow_none : bool |
|
749 | 749 | Indicates whether None is allowed as a value. |
|
750 | 750 | |
|
751 | 751 | Default Value |
|
752 | 752 | ------------- |
|
753 | 753 | If both ``args`` and ``kw`` are None, then the default value is None. |
|
754 | 754 | If ``args`` is a tuple and ``kw`` is a dict, then the default is |
|
755 | 755 | created as ``klass(*args, **kw)``. If either ``args`` or ``kw`` is |
|
756 | 756 | not (but not both), None is replace by ``()`` or ``{}``. |
|
757 | 757 | """ |
|
758 | 758 | |
|
759 | 759 | self._allow_none = allow_none |
|
760 | 760 | |
|
761 | 761 | if (klass is None) or (not (inspect.isclass(klass) or isinstance(klass, basestring))): |
|
762 | 762 | raise TraitError('The klass argument must be a class' |
|
763 | 763 | ' you gave: %r' % klass) |
|
764 | 764 | self.klass = klass |
|
765 | 765 | |
|
766 | 766 | # self.klass is a class, so handle default_value |
|
767 | 767 | if args is None and kw is None: |
|
768 | 768 | default_value = None |
|
769 | 769 | else: |
|
770 | 770 | if args is None: |
|
771 | 771 | # kw is not None |
|
772 | 772 | args = () |
|
773 | 773 | elif kw is None: |
|
774 | 774 | # args is not None |
|
775 | 775 | kw = {} |
|
776 | 776 | |
|
777 | 777 | if not isinstance(kw, dict): |
|
778 | 778 | raise TraitError("The 'kw' argument must be a dict or None.") |
|
779 | 779 | if not isinstance(args, tuple): |
|
780 | 780 | raise TraitError("The 'args' argument must be a tuple or None.") |
|
781 | 781 | |
|
782 | 782 | default_value = DefaultValueGenerator(*args, **kw) |
|
783 | 783 | |
|
784 | 784 | super(Instance, self).__init__(default_value, **metadata) |
|
785 | 785 | |
|
786 | 786 | def validate(self, obj, value): |
|
787 | 787 | if value is None: |
|
788 | 788 | if self._allow_none: |
|
789 | 789 | return value |
|
790 | 790 | self.error(obj, value) |
|
791 | 791 | |
|
792 | 792 | if isinstance(value, self.klass): |
|
793 | 793 | return value |
|
794 | 794 | else: |
|
795 | 795 | self.error(obj, value) |
|
796 | 796 | |
|
797 | 797 | def info(self): |
|
798 | 798 | if isinstance(self.klass, basestring): |
|
799 | 799 | klass = self.klass |
|
800 | 800 | else: |
|
801 | 801 | klass = self.klass.__name__ |
|
802 | 802 | result = class_of(klass) |
|
803 | 803 | if self._allow_none: |
|
804 | 804 | return result + ' or None' |
|
805 | 805 | |
|
806 | 806 | return result |
|
807 | 807 | |
|
808 | 808 | def instance_init(self, obj): |
|
809 | 809 | self._resolve_classes() |
|
810 | 810 | super(Instance, self).instance_init(obj) |
|
811 | 811 | |
|
812 | 812 | def _resolve_classes(self): |
|
813 | 813 | if isinstance(self.klass, basestring): |
|
814 | 814 | self.klass = import_item(self.klass) |
|
815 | 815 | |
|
816 | 816 | def get_default_value(self): |
|
817 | 817 | """Instantiate a default value instance. |
|
818 | 818 | |
|
819 | 819 | This is called when the containing HasTraits classes' |
|
820 | 820 | :meth:`__new__` method is called to ensure that a unique instance |
|
821 | 821 | is created for each HasTraits instance. |
|
822 | 822 | """ |
|
823 | 823 | dv = self.default_value |
|
824 | 824 | if isinstance(dv, DefaultValueGenerator): |
|
825 | 825 | return dv.generate(self.klass) |
|
826 | 826 | else: |
|
827 | 827 | return dv |
|
828 | 828 | |
|
829 | 829 | |
|
830 | 830 | class This(ClassBasedTraitType): |
|
831 | 831 | """A trait for instances of the class containing this trait. |
|
832 | 832 | |
|
833 | 833 | Because how how and when class bodies are executed, the ``This`` |
|
834 | 834 | trait can only have a default value of None. This, and because we |
|
835 | 835 | always validate default values, ``allow_none`` is *always* true. |
|
836 | 836 | """ |
|
837 | 837 | |
|
838 | 838 | info_text = 'an instance of the same type as the receiver or None' |
|
839 | 839 | |
|
840 | 840 | def __init__(self, **metadata): |
|
841 | 841 | super(This, self).__init__(None, **metadata) |
|
842 | 842 | |
|
843 | 843 | def validate(self, obj, value): |
|
844 | 844 | # What if value is a superclass of obj.__class__? This is |
|
845 | 845 | # complicated if it was the superclass that defined the This |
|
846 | 846 | # trait. |
|
847 | 847 | if isinstance(value, self.this_class) or (value is None): |
|
848 | 848 | return value |
|
849 | 849 | else: |
|
850 | 850 | self.error(obj, value) |
|
851 | 851 | |
|
852 | 852 | |
|
853 | 853 | #----------------------------------------------------------------------------- |
|
854 | 854 | # Basic TraitTypes implementations/subclasses |
|
855 | 855 | #----------------------------------------------------------------------------- |
|
856 | 856 | |
|
857 | 857 | |
|
858 | 858 | class Any(TraitType): |
|
859 | 859 | default_value = None |
|
860 | 860 | info_text = 'any value' |
|
861 | 861 | |
|
862 | 862 | |
|
863 | 863 | class Int(TraitType): |
|
864 | 864 | """A integer trait.""" |
|
865 | 865 | |
|
866 | 866 | default_value = 0 |
|
867 | 867 | info_text = 'an integer' |
|
868 | 868 | |
|
869 | 869 | def validate(self, obj, value): |
|
870 | 870 | if isinstance(value, int): |
|
871 | 871 | return value |
|
872 | 872 | self.error(obj, value) |
|
873 | 873 | |
|
874 | 874 | class CInt(Int): |
|
875 | 875 | """A casting version of the int trait.""" |
|
876 | 876 | |
|
877 | 877 | def validate(self, obj, value): |
|
878 | 878 | try: |
|
879 | 879 | return int(value) |
|
880 | 880 | except: |
|
881 | 881 | self.error(obj, value) |
|
882 | 882 | |
|
883 | 883 | |
|
884 | 884 | class Long(TraitType): |
|
885 | 885 | """A long integer trait.""" |
|
886 | 886 | |
|
887 | 887 | default_value = 0L |
|
888 | 888 | info_text = 'a long' |
|
889 | 889 | |
|
890 | 890 | def validate(self, obj, value): |
|
891 | 891 | if isinstance(value, long): |
|
892 | 892 | return value |
|
893 | 893 | if isinstance(value, int): |
|
894 | 894 | return long(value) |
|
895 | 895 | self.error(obj, value) |
|
896 | 896 | |
|
897 | 897 | |
|
898 | 898 | class CLong(Long): |
|
899 | 899 | """A casting version of the long integer trait.""" |
|
900 | 900 | |
|
901 | 901 | def validate(self, obj, value): |
|
902 | 902 | try: |
|
903 | 903 | return long(value) |
|
904 | 904 | except: |
|
905 | 905 | self.error(obj, value) |
|
906 | 906 | |
|
907 | 907 | |
|
908 | 908 | class Float(TraitType): |
|
909 | 909 | """A float trait.""" |
|
910 | 910 | |
|
911 | 911 | default_value = 0.0 |
|
912 | 912 | info_text = 'a float' |
|
913 | 913 | |
|
914 | 914 | def validate(self, obj, value): |
|
915 | 915 | if isinstance(value, float): |
|
916 | 916 | return value |
|
917 | 917 | if isinstance(value, int): |
|
918 | 918 | return float(value) |
|
919 | 919 | self.error(obj, value) |
|
920 | 920 | |
|
921 | 921 | |
|
922 | 922 | class CFloat(Float): |
|
923 | 923 | """A casting version of the float trait.""" |
|
924 | 924 | |
|
925 | 925 | def validate(self, obj, value): |
|
926 | 926 | try: |
|
927 | 927 | return float(value) |
|
928 | 928 | except: |
|
929 | 929 | self.error(obj, value) |
|
930 | 930 | |
|
931 | 931 | class Complex(TraitType): |
|
932 | 932 | """A trait for complex numbers.""" |
|
933 | 933 | |
|
934 | 934 | default_value = 0.0 + 0.0j |
|
935 | 935 | info_text = 'a complex number' |
|
936 | 936 | |
|
937 | 937 | def validate(self, obj, value): |
|
938 | 938 | if isinstance(value, complex): |
|
939 | 939 | return value |
|
940 | 940 | if isinstance(value, (float, int)): |
|
941 | 941 | return complex(value) |
|
942 | 942 | self.error(obj, value) |
|
943 | 943 | |
|
944 | 944 | |
|
945 | 945 | class CComplex(Complex): |
|
946 | 946 | """A casting version of the complex number trait.""" |
|
947 | 947 | |
|
948 | 948 | def validate (self, obj, value): |
|
949 | 949 | try: |
|
950 | 950 | return complex(value) |
|
951 | 951 | except: |
|
952 | 952 | self.error(obj, value) |
|
953 | 953 | |
|
954 | 954 | |
|
955 | 955 | class Bytes(TraitType): |
|
956 | 956 | """A trait for strings.""" |
|
957 | 957 | |
|
958 | 958 | default_value = '' |
|
959 | 959 | info_text = 'a string' |
|
960 | 960 | |
|
961 | 961 | def validate(self, obj, value): |
|
962 | 962 | if isinstance(value, bytes): |
|
963 | 963 | return value |
|
964 | 964 | self.error(obj, value) |
|
965 | 965 | |
|
966 | 966 | |
|
967 | 967 | class CBytes(Bytes): |
|
968 | 968 | """A casting version of the string trait.""" |
|
969 | 969 | |
|
970 | 970 | def validate(self, obj, value): |
|
971 | 971 | try: |
|
972 | 972 | return bytes(value) |
|
973 | 973 | except: |
|
974 | try: | |
|
975 | return unicode(value) | |
|
976 | except: | |
|
977 | self.error(obj, value) | |
|
974 | self.error(obj, value) | |
|
978 | 975 | |
|
979 | 976 | |
|
980 | 977 | class Unicode(TraitType): |
|
981 | 978 | """A trait for unicode strings.""" |
|
982 | 979 | |
|
983 | 980 | default_value = u'' |
|
984 | 981 | info_text = 'a unicode string' |
|
985 | 982 | |
|
986 | 983 | def validate(self, obj, value): |
|
987 | 984 | if isinstance(value, unicode): |
|
988 | 985 | return value |
|
989 | 986 | if isinstance(value, bytes): |
|
990 | 987 | return unicode(value) |
|
991 | 988 | self.error(obj, value) |
|
992 | 989 | |
|
993 | 990 | |
|
994 | 991 | class CUnicode(Unicode): |
|
995 | 992 | """A casting version of the unicode trait.""" |
|
996 | 993 | |
|
997 | 994 | def validate(self, obj, value): |
|
998 | 995 | try: |
|
999 | 996 | return unicode(value) |
|
1000 | 997 | except: |
|
1001 | 998 | self.error(obj, value) |
|
1002 | 999 | |
|
1003 | 1000 | if sys.version_info[0] < 3: |
|
1004 | 1001 | Str, CStr = Bytes, CBytes |
|
1005 | 1002 | else: |
|
1006 | 1003 | Str, CStr = Unicode, CUnicode |
|
1007 | 1004 | |
|
1008 | 1005 | |
|
1009 | 1006 | class Bool(TraitType): |
|
1010 | 1007 | """A boolean (True, False) trait.""" |
|
1011 | 1008 | |
|
1012 | 1009 | default_value = False |
|
1013 | 1010 | info_text = 'a boolean' |
|
1014 | 1011 | |
|
1015 | 1012 | def validate(self, obj, value): |
|
1016 | 1013 | if isinstance(value, bool): |
|
1017 | 1014 | return value |
|
1018 | 1015 | self.error(obj, value) |
|
1019 | 1016 | |
|
1020 | 1017 | |
|
1021 | 1018 | class CBool(Bool): |
|
1022 | 1019 | """A casting version of the boolean trait.""" |
|
1023 | 1020 | |
|
1024 | 1021 | def validate(self, obj, value): |
|
1025 | 1022 | try: |
|
1026 | 1023 | return bool(value) |
|
1027 | 1024 | except: |
|
1028 | 1025 | self.error(obj, value) |
|
1029 | 1026 | |
|
1030 | 1027 | |
|
1031 | 1028 | class Enum(TraitType): |
|
1032 | 1029 | """An enum that whose value must be in a given sequence.""" |
|
1033 | 1030 | |
|
1034 | 1031 | def __init__(self, values, default_value=None, allow_none=True, **metadata): |
|
1035 | 1032 | self.values = values |
|
1036 | 1033 | self._allow_none = allow_none |
|
1037 | 1034 | super(Enum, self).__init__(default_value, **metadata) |
|
1038 | 1035 | |
|
1039 | 1036 | def validate(self, obj, value): |
|
1040 | 1037 | if value is None: |
|
1041 | 1038 | if self._allow_none: |
|
1042 | 1039 | return value |
|
1043 | 1040 | |
|
1044 | 1041 | if value in self.values: |
|
1045 | 1042 | return value |
|
1046 | 1043 | self.error(obj, value) |
|
1047 | 1044 | |
|
1048 | 1045 | def info(self): |
|
1049 | 1046 | """ Returns a description of the trait.""" |
|
1050 | 1047 | result = 'any of ' + repr(self.values) |
|
1051 | 1048 | if self._allow_none: |
|
1052 | 1049 | return result + ' or None' |
|
1053 | 1050 | return result |
|
1054 | 1051 | |
|
1055 | 1052 | class CaselessStrEnum(Enum): |
|
1056 | 1053 | """An enum of strings that are caseless in validate.""" |
|
1057 | 1054 | |
|
1058 | 1055 | def validate(self, obj, value): |
|
1059 | 1056 | if value is None: |
|
1060 | 1057 | if self._allow_none: |
|
1061 | 1058 | return value |
|
1062 | 1059 | |
|
1063 | 1060 | if not isinstance(value, str): |
|
1064 | 1061 | self.error(obj, value) |
|
1065 | 1062 | |
|
1066 | 1063 | for v in self.values: |
|
1067 | 1064 | if v.lower() == value.lower(): |
|
1068 | 1065 | return v |
|
1069 | 1066 | self.error(obj, value) |
|
1070 | 1067 | |
|
1071 | 1068 | class Container(Instance): |
|
1072 | 1069 | """An instance of a container (list, set, etc.) |
|
1073 | 1070 | |
|
1074 | 1071 | To be subclassed by overriding klass. |
|
1075 | 1072 | """ |
|
1076 | 1073 | klass = None |
|
1077 | 1074 | _valid_defaults = SequenceTypes |
|
1078 | 1075 | _trait = None |
|
1079 | 1076 | |
|
1080 | 1077 | def __init__(self, trait=None, default_value=None, allow_none=True, |
|
1081 | 1078 | **metadata): |
|
1082 | 1079 | """Create a container trait type from a list, set, or tuple. |
|
1083 | 1080 | |
|
1084 | 1081 | The default value is created by doing ``List(default_value)``, |
|
1085 | 1082 | which creates a copy of the ``default_value``. |
|
1086 | 1083 | |
|
1087 | 1084 | ``trait`` can be specified, which restricts the type of elements |
|
1088 | 1085 | in the container to that TraitType. |
|
1089 | 1086 | |
|
1090 | 1087 | If only one arg is given and it is not a Trait, it is taken as |
|
1091 | 1088 | ``default_value``: |
|
1092 | 1089 | |
|
1093 | 1090 | ``c = List([1,2,3])`` |
|
1094 | 1091 | |
|
1095 | 1092 | Parameters |
|
1096 | 1093 | ---------- |
|
1097 | 1094 | |
|
1098 | 1095 | trait : TraitType [ optional ] |
|
1099 | 1096 | the type for restricting the contents of the Container. If unspecified, |
|
1100 | 1097 | types are not checked. |
|
1101 | 1098 | |
|
1102 | 1099 | default_value : SequenceType [ optional ] |
|
1103 | 1100 | The default value for the Trait. Must be list/tuple/set, and |
|
1104 | 1101 | will be cast to the container type. |
|
1105 | 1102 | |
|
1106 | 1103 | allow_none : Bool [ default True ] |
|
1107 | 1104 | Whether to allow the value to be None |
|
1108 | 1105 | |
|
1109 | 1106 | **metadata : any |
|
1110 | 1107 | further keys for extensions to the Trait (e.g. config) |
|
1111 | 1108 | |
|
1112 | 1109 | """ |
|
1113 | 1110 | istrait = lambda t: isinstance(t, type) and issubclass(t, TraitType) |
|
1114 | 1111 | |
|
1115 | 1112 | # allow List([values]): |
|
1116 | 1113 | if default_value is None and not istrait(trait): |
|
1117 | 1114 | default_value = trait |
|
1118 | 1115 | trait = None |
|
1119 | 1116 | |
|
1120 | 1117 | if default_value is None: |
|
1121 | 1118 | args = () |
|
1122 | 1119 | elif isinstance(default_value, self._valid_defaults): |
|
1123 | 1120 | args = (default_value,) |
|
1124 | 1121 | else: |
|
1125 | 1122 | raise TypeError('default value of %s was %s' %(self.__class__.__name__, default_value)) |
|
1126 | 1123 | |
|
1127 | 1124 | if istrait(trait): |
|
1128 | 1125 | self._trait = trait() |
|
1129 | 1126 | self._trait.name = 'element' |
|
1130 | 1127 | elif trait is not None: |
|
1131 | 1128 | raise TypeError("`trait` must be a Trait or None, got %s"%repr_type(trait)) |
|
1132 | 1129 | |
|
1133 | 1130 | super(Container,self).__init__(klass=self.klass, args=args, |
|
1134 | 1131 | allow_none=allow_none, **metadata) |
|
1135 | 1132 | |
|
1136 | 1133 | def element_error(self, obj, element, validator): |
|
1137 | 1134 | e = "Element of the '%s' trait of %s instance must be %s, but a value of %s was specified." \ |
|
1138 | 1135 | % (self.name, class_of(obj), validator.info(), repr_type(element)) |
|
1139 | 1136 | raise TraitError(e) |
|
1140 | 1137 | |
|
1141 | 1138 | def validate(self, obj, value): |
|
1142 | 1139 | value = super(Container, self).validate(obj, value) |
|
1143 | 1140 | if value is None: |
|
1144 | 1141 | return value |
|
1145 | 1142 | |
|
1146 | 1143 | value = self.validate_elements(obj, value) |
|
1147 | 1144 | |
|
1148 | 1145 | return value |
|
1149 | 1146 | |
|
1150 | 1147 | def validate_elements(self, obj, value): |
|
1151 | 1148 | validated = [] |
|
1152 | 1149 | if self._trait is None or isinstance(self._trait, Any): |
|
1153 | 1150 | return value |
|
1154 | 1151 | for v in value: |
|
1155 | 1152 | try: |
|
1156 | 1153 | v = self._trait.validate(obj, v) |
|
1157 | 1154 | except TraitError: |
|
1158 | 1155 | self.element_error(obj, v, self._trait) |
|
1159 | 1156 | else: |
|
1160 | 1157 | validated.append(v) |
|
1161 | 1158 | return self.klass(validated) |
|
1162 | 1159 | |
|
1163 | 1160 | |
|
1164 | 1161 | class List(Container): |
|
1165 | 1162 | """An instance of a Python list.""" |
|
1166 | 1163 | klass = list |
|
1167 | 1164 | |
|
1168 | 1165 | def __init__(self, trait=None, default_value=None, minlen=0, maxlen=sys.maxint, |
|
1169 | 1166 | allow_none=True, **metadata): |
|
1170 | 1167 | """Create a List trait type from a list, set, or tuple. |
|
1171 | 1168 | |
|
1172 | 1169 | The default value is created by doing ``List(default_value)``, |
|
1173 | 1170 | which creates a copy of the ``default_value``. |
|
1174 | 1171 | |
|
1175 | 1172 | ``trait`` can be specified, which restricts the type of elements |
|
1176 | 1173 | in the container to that TraitType. |
|
1177 | 1174 | |
|
1178 | 1175 | If only one arg is given and it is not a Trait, it is taken as |
|
1179 | 1176 | ``default_value``: |
|
1180 | 1177 | |
|
1181 | 1178 | ``c = List([1,2,3])`` |
|
1182 | 1179 | |
|
1183 | 1180 | Parameters |
|
1184 | 1181 | ---------- |
|
1185 | 1182 | |
|
1186 | 1183 | trait : TraitType [ optional ] |
|
1187 | 1184 | the type for restricting the contents of the Container. If unspecified, |
|
1188 | 1185 | types are not checked. |
|
1189 | 1186 | |
|
1190 | 1187 | default_value : SequenceType [ optional ] |
|
1191 | 1188 | The default value for the Trait. Must be list/tuple/set, and |
|
1192 | 1189 | will be cast to the container type. |
|
1193 | 1190 | |
|
1194 | 1191 | minlen : Int [ default 0 ] |
|
1195 | 1192 | The minimum length of the input list |
|
1196 | 1193 | |
|
1197 | 1194 | maxlen : Int [ default sys.maxint ] |
|
1198 | 1195 | The maximum length of the input list |
|
1199 | 1196 | |
|
1200 | 1197 | allow_none : Bool [ default True ] |
|
1201 | 1198 | Whether to allow the value to be None |
|
1202 | 1199 | |
|
1203 | 1200 | **metadata : any |
|
1204 | 1201 | further keys for extensions to the Trait (e.g. config) |
|
1205 | 1202 | |
|
1206 | 1203 | """ |
|
1207 | 1204 | self._minlen = minlen |
|
1208 | 1205 | self._maxlen = maxlen |
|
1209 | 1206 | super(List, self).__init__(trait=trait, default_value=default_value, |
|
1210 | 1207 | allow_none=allow_none, **metadata) |
|
1211 | 1208 | |
|
1212 | 1209 | def length_error(self, obj, value): |
|
1213 | 1210 | e = "The '%s' trait of %s instance must be of length %i <= L <= %i, but a value of %s was specified." \ |
|
1214 | 1211 | % (self.name, class_of(obj), self._minlen, self._maxlen, value) |
|
1215 | 1212 | raise TraitError(e) |
|
1216 | 1213 | |
|
1217 | 1214 | def validate_elements(self, obj, value): |
|
1218 | 1215 | length = len(value) |
|
1219 | 1216 | if length < self._minlen or length > self._maxlen: |
|
1220 | 1217 | self.length_error(obj, value) |
|
1221 | 1218 | |
|
1222 | 1219 | return super(List, self).validate_elements(obj, value) |
|
1223 | 1220 | |
|
1224 | 1221 | |
|
1225 | 1222 | class Set(Container): |
|
1226 | 1223 | """An instance of a Python set.""" |
|
1227 | 1224 | klass = set |
|
1228 | 1225 | |
|
1229 | 1226 | class Tuple(Container): |
|
1230 | 1227 | """An instance of a Python tuple.""" |
|
1231 | 1228 | klass = tuple |
|
1232 | 1229 | |
|
1233 | 1230 | def __init__(self, *traits, **metadata): |
|
1234 | 1231 | """Tuple(*traits, default_value=None, allow_none=True, **medatata) |
|
1235 | 1232 | |
|
1236 | 1233 | Create a tuple from a list, set, or tuple. |
|
1237 | 1234 | |
|
1238 | 1235 | Create a fixed-type tuple with Traits: |
|
1239 | 1236 | |
|
1240 | 1237 | ``t = Tuple(Int, Str, CStr)`` |
|
1241 | 1238 | |
|
1242 | 1239 | would be length 3, with Int,Str,CStr for each element. |
|
1243 | 1240 | |
|
1244 | 1241 | If only one arg is given and it is not a Trait, it is taken as |
|
1245 | 1242 | default_value: |
|
1246 | 1243 | |
|
1247 | 1244 | ``t = Tuple((1,2,3))`` |
|
1248 | 1245 | |
|
1249 | 1246 | Otherwise, ``default_value`` *must* be specified by keyword. |
|
1250 | 1247 | |
|
1251 | 1248 | Parameters |
|
1252 | 1249 | ---------- |
|
1253 | 1250 | |
|
1254 | 1251 | *traits : TraitTypes [ optional ] |
|
1255 | 1252 | the tsype for restricting the contents of the Tuple. If unspecified, |
|
1256 | 1253 | types are not checked. If specified, then each positional argument |
|
1257 | 1254 | corresponds to an element of the tuple. Tuples defined with traits |
|
1258 | 1255 | are of fixed length. |
|
1259 | 1256 | |
|
1260 | 1257 | default_value : SequenceType [ optional ] |
|
1261 | 1258 | The default value for the Tuple. Must be list/tuple/set, and |
|
1262 | 1259 | will be cast to a tuple. If `traits` are specified, the |
|
1263 | 1260 | `default_value` must conform to the shape and type they specify. |
|
1264 | 1261 | |
|
1265 | 1262 | allow_none : Bool [ default True ] |
|
1266 | 1263 | Whether to allow the value to be None |
|
1267 | 1264 | |
|
1268 | 1265 | **metadata : any |
|
1269 | 1266 | further keys for extensions to the Trait (e.g. config) |
|
1270 | 1267 | |
|
1271 | 1268 | """ |
|
1272 | 1269 | default_value = metadata.pop('default_value', None) |
|
1273 | 1270 | allow_none = metadata.pop('allow_none', True) |
|
1274 | 1271 | |
|
1275 | 1272 | istrait = lambda t: isinstance(t, type) and issubclass(t, TraitType) |
|
1276 | 1273 | |
|
1277 | 1274 | # allow Tuple((values,)): |
|
1278 | 1275 | if len(traits) == 1 and default_value is None and not istrait(traits[0]): |
|
1279 | 1276 | default_value = traits[0] |
|
1280 | 1277 | traits = () |
|
1281 | 1278 | |
|
1282 | 1279 | if default_value is None: |
|
1283 | 1280 | args = () |
|
1284 | 1281 | elif isinstance(default_value, self._valid_defaults): |
|
1285 | 1282 | args = (default_value,) |
|
1286 | 1283 | else: |
|
1287 | 1284 | raise TypeError('default value of %s was %s' %(self.__class__.__name__, default_value)) |
|
1288 | 1285 | |
|
1289 | 1286 | self._traits = [] |
|
1290 | 1287 | for trait in traits: |
|
1291 | 1288 | t = trait() |
|
1292 | 1289 | t.name = 'element' |
|
1293 | 1290 | self._traits.append(t) |
|
1294 | 1291 | |
|
1295 | 1292 | if self._traits and default_value is None: |
|
1296 | 1293 | # don't allow default to be an empty container if length is specified |
|
1297 | 1294 | args = None |
|
1298 | 1295 | super(Container,self).__init__(klass=self.klass, args=args, |
|
1299 | 1296 | allow_none=allow_none, **metadata) |
|
1300 | 1297 | |
|
1301 | 1298 | def validate_elements(self, obj, value): |
|
1302 | 1299 | if not self._traits: |
|
1303 | 1300 | # nothing to validate |
|
1304 | 1301 | return value |
|
1305 | 1302 | if len(value) != len(self._traits): |
|
1306 | 1303 | e = "The '%s' trait of %s instance requires %i elements, but a value of %s was specified." \ |
|
1307 | 1304 | % (self.name, class_of(obj), len(self._traits), repr_type(value)) |
|
1308 | 1305 | raise TraitError(e) |
|
1309 | 1306 | |
|
1310 | 1307 | validated = [] |
|
1311 | 1308 | for t,v in zip(self._traits, value): |
|
1312 | 1309 | try: |
|
1313 | 1310 | v = t.validate(obj, v) |
|
1314 | 1311 | except TraitError: |
|
1315 | 1312 | self.element_error(obj, v, t) |
|
1316 | 1313 | else: |
|
1317 | 1314 | validated.append(v) |
|
1318 | 1315 | return tuple(validated) |
|
1319 | 1316 | |
|
1320 | 1317 | |
|
1321 | 1318 | class Dict(Instance): |
|
1322 | 1319 | """An instance of a Python dict.""" |
|
1323 | 1320 | |
|
1324 | 1321 | def __init__(self, default_value=None, allow_none=True, **metadata): |
|
1325 | 1322 | """Create a dict trait type from a dict. |
|
1326 | 1323 | |
|
1327 | 1324 | The default value is created by doing ``dict(default_value)``, |
|
1328 | 1325 | which creates a copy of the ``default_value``. |
|
1329 | 1326 | """ |
|
1330 | 1327 | if default_value is None: |
|
1331 | 1328 | args = ((),) |
|
1332 | 1329 | elif isinstance(default_value, dict): |
|
1333 | 1330 | args = (default_value,) |
|
1334 | 1331 | elif isinstance(default_value, SequenceTypes): |
|
1335 | 1332 | args = (default_value,) |
|
1336 | 1333 | else: |
|
1337 | 1334 | raise TypeError('default value of Dict was %s' % default_value) |
|
1338 | 1335 | |
|
1339 | 1336 | super(Dict,self).__init__(klass=dict, args=args, |
|
1340 | 1337 | allow_none=allow_none, **metadata) |
|
1341 | 1338 | |
|
1342 | 1339 | class TCPAddress(TraitType): |
|
1343 | 1340 | """A trait for an (ip, port) tuple. |
|
1344 | 1341 | |
|
1345 | 1342 | This allows for both IPv4 IP addresses as well as hostnames. |
|
1346 | 1343 | """ |
|
1347 | 1344 | |
|
1348 | 1345 | default_value = ('127.0.0.1', 0) |
|
1349 | 1346 | info_text = 'an (ip, port) tuple' |
|
1350 | 1347 | |
|
1351 | 1348 | def validate(self, obj, value): |
|
1352 | 1349 | if isinstance(value, tuple): |
|
1353 | 1350 | if len(value) == 2: |
|
1354 | 1351 | if isinstance(value[0], basestring) and isinstance(value[1], int): |
|
1355 | 1352 | port = value[1] |
|
1356 | 1353 | if port >= 0 and port <= 65535: |
|
1357 | 1354 | return value |
|
1358 | 1355 | self.error(obj, value) |
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