/usr/share/pyshared/lazr.enum-1.1.4.egg-info/PKG-INFO is in python-lazr.enum 1.1.4-0ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 | Metadata-Version: 1.1
Name: lazr.enum
Version: 1.1.4
Summary: Enums with zope.schema vocabulary support and database-friendly conveniences.
Home-page: https://launchpad.net/lazr.enum
Author: LAZR Developers
Author-email: lazr-developers@lists.launchpad.net
License: LGPL v3
Download-URL: https://launchpad.net/lazr.enum/+download
Description: ..
This file is part of lazr.enum.
lazr.enum is free software: you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, version 3 of the License.
lazr.enum is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with lazr.enum. If not, see <http://www.gnu.org/licenses/>.
Enumerated Types
****************
Enumerated types are used primarily in two distinct places in the Launchpad
code: selector types; and database types.
Simple enumerated types do not have values, whereas database enumerated
types are a mapping from an integer value to something meaningful in the
code.
>>> from lazr.enum import (
... EnumeratedType, DBEnumeratedType, Item, DBItem, use_template)
The `enum` values of EnumeratedTypes are instances of Item.
>>> class Fruit(EnumeratedType):
... "A choice of fruit."
... APPLE = Item('Apple')
... PEAR = Item('Pear')
... ORANGE = Item('Orange')
===================
IVocabulary support
===================
Enumerated types support IVocabularyTokenized.
>>> from zope.interface.verify import verifyObject
>>> from zope.schema.interfaces import (
... ITitledTokenizedTerm, IVocabularyTokenized)
>>> verifyObject(IVocabularyTokenized, Fruit)
True
The items themselves do not support any interface. Items returned
by the methods for vocabularies return wrapped items that support
the ITitledTokenizedTerm interface.
The token used to identify terms in the vocabulary is the name of the
Item variable.
>>> item = Fruit.getTermByToken('APPLE')
>>> type(item)
<class 'lazr.enum...TokenizedItem'>
>>> verifyObject(ITitledTokenizedTerm, item)
True
TokenizedItems have three attributes (in order to support
ITitledTokenizedTerm):
>>> item.value
<Item Fruit.APPLE, Apple>
>>> item.token
'APPLE'
>>> item.title
'Apple'
>>> Fruit.getTermByToken('apple').value
<Item Fruit.APPLE, Apple>
The length of an EnumeratedType returns the number of items it has.
>>> print len(Fruit)
3
===========================
The EnumeratedType registry
===========================
All enumerated types that are created are added to the
enumerated_type_registry.
>>> from lazr.enum import enumerated_type_registry
The enumerated_type_registry maps the name of the enumerated type to the type
itself.
>>> 'Fruit' in enumerated_type_registry
True
>>> enumerated_type_registry['Fruit']
<EnumeratedType 'Fruit'>
You cannot redefine an existing enumerated type, nor create another enumerated
type with the same name as an existing type.
>>> class BranchType(EnumeratedType):
... BAR = Item('Bar')
...
>>> BranchType.name = 'AltBranchType'
>>> class BranchType(EnumeratedType):
... FOO = Item('Foo')
Traceback (most recent call last):
...
TypeError: An enumerated type already exists with the name BranchType
(...AltBranchType).
======================
Enumerated Type basics
======================
An EnumeratedType has a name and a description. The name is the same as the
class name, and the description is the docstring for the class.
>>> print Fruit.name
Fruit
>>> print Fruit.description
A choice of fruit.
If you do not specify an explicit sort_order for the items of the
EnumeratedType one is created for you. This is tuple of the tokens.
>>> print Fruit.sort_order
('APPLE', 'PEAR', 'ORANGE')
The items of an enumerated type can be iterated over. However the type that
is returned by the iteration is the TokenizedItem, not the item itself.
>>> for item in Fruit:
... print item.token, item.title
APPLE Apple
PEAR Pear
ORANGE Orange
Items can also optionally have a url associated with them.
>>> class Guitar(EnumeratedType):
... FENDER = Item('Fender', url='http://www.fender.com')
... RICK = Item('Rickenbacker', url='http://www.rickenbacker.com')
... GIBSON = Item('Gibson', url='http://www.gibson.com')
... FRANKENBASS = Item('Home built')
>>> print Guitar.FENDER.url
http://www.fender.com
>>> print Guitar.FRANKENBASS.url
None
Items in an enumerator support comparison and equality checks. Comparison
is based on the sort order of the items.
>>> apple = Fruit.APPLE
>>> pear = Fruit.PEAR
>>> orange = Fruit.ORANGE
>>> apple < pear
True
>>> apple == pear
False
>>> apple == apple
True
>>> apple != pear
True
>>> apple > pear
False
>>> pear < orange
True
>>> apple < orange
True
Items which are not in an enumerator always compare as False.
>>> from lazr.enum import Item
>>> Item('a') == Item('b')
False
The string representation of an Item is the title, and the representation
also shows the enumeration that the Item is from.
>>> print apple
Apple
>>> print repr(apple)
<Item Fruit.APPLE, Apple>
The `items` attribute of an enumerated type is not a list, but a class that
provides iteration over the items, and access to the Item attributes through
either the name of the Item, or the database value if there is one.
The primary use of this is to provide a backwards compatible accessor for
items, but it also provides a suitable alternative to getattr.
>>> name = 'APPLE'
>>> Fruit.items[name]
<Item Fruit.APPLE, Apple>
>>> getattr(Fruit, name)
<Item Fruit.APPLE, Apple>
=========================
Database Enumerated Types
=========================
A very common use of enumerated types are to give semantic meaning to integer
values stored in database columns. EnumeratedType Items themselves don't have
any integer values.
The DBEnumeratedType provides the semantic framework for a type that is used to
map integer values to python enumerated values.
>>> # Remove the existing reference to BranchType from the registry
>>> del enumerated_type_registry['BranchType']
>>> class BranchType(DBEnumeratedType):
... HOSTED = DBItem(1, """
... Hosted
...
... Hosted braches use the supermirror as the main repository
... for the branch.""")
...
... MIRRORED = DBItem(2, """
... Mirrored
...
... Mirrored branches are "pulled" from a remote location.""")
...
... IMPORTED = DBItem(3, """
... Imported
...
... Imported branches are natively maintained in CVS or SVN""")
Note carefully that the value of a DBItem is the integer representation. But
the value of the TokenizedItem is the DBItem itself.
>>> hosted = BranchType.HOSTED
>>> hosted.value
1
>>> hosted == BranchType.HOSTED
True
>>> tokenized_item = BranchType.getTermByToken('HOSTED')
>>> tokenized_item.value
<DBItem BranchType.HOSTED, (1) Hosted>
DBEnumeratedTypes also support IVocabularyTokenized
>>> verifyObject(IVocabularyTokenized, BranchType)
True
The items attribute of DBEnumeratedTypes provide a mapping from the database
values to the DBItems.
>>> BranchType.items[3]
<DBItem BranchType.IMPORTED, (3) Imported>
The items also support the url field.
>>> class Bass(DBEnumeratedType):
... FENDER = DBItem(10, 'Fender', url='http://www.fender.com')
... RICK = DBItem(20, 'Rickenbacker',
... url='http://www.rickenbacker.com')
... GIBSON = DBItem(30, 'Gibson', url='http://www.gibson.com')
... FRANKENBASS = DBItem(40, 'Home built')
>>> print Bass.FENDER.url
http://www.fender.com
>>> print Bass.FRANKENBASS.url
None
Items in a DBEnumeratedType class must be of type DBItem.
>>> class BadItemType(DBEnumeratedType):
... TESTING = Item("Testing")
Traceback (most recent call last):
...
TypeError: Items must be of the appropriate type for the DBEnumeratedType,
__builtin__.BadItemType.TESTING
You are not able to define a DBEnumeratedType that has two different
DBItems that map to the same numeric value.
>>> class TwoMapping(DBEnumeratedType):
... FIRST = DBItem(42, 'First')
... SECOND = DBItem(42, 'Second')
Traceback (most recent call last):
...
TypeError: Two DBItems with the same value 42 (FIRST, SECOND)
=========================
Overriding the sort order
=========================
By default the sort order of the items in an enumerated type is defined by the
order in which the Items are declared. This my be overridden by specifying
a sort_order attribute in the class.
If a sort_order is specified, it has to specify every item in the enumeration.
>>> class AnimalClassification(EnumeratedType):
... sort_order = "REPTILE", "INSECT", "MAMMAL"
... INSECT = Item("Insect")
... MAMMAL = Item("Mammal")
... FISH = Item("Fish")
... REPTILE = Item("Reptile")
Traceback (most recent call last):
...
TypeError: sort_order for EnumeratedType must contain all and only Item instances ...
The sort_order may also appear anywhere in the definition of the class,
although convention has it that it appears first, before the Item instances.
>>> class AnimalClassification(EnumeratedType):
... sort_order = "REPTILE", "FISH", "INSECT", "MAMMAL"
... INSECT = Item("Insect")
... MAMMAL = Item("Mammal")
... FISH = Item("Fish")
... REPTILE = Item("Reptile")
The items attribute of the enumerated type is ordered based on the sort_order.
The items attribute is also used to control iteration using __iter__.
>>> for item in AnimalClassification.items:
... print item.title
Reptile
Fish
Insect
Mammal
The sort order also drives the comparison operations.
>>> reptile, fish, insect, mammal = AnimalClassification.items
>>> reptile < fish < insect < mammal
True
==========================
Extending enumerated types
==========================
The simplest way to extend a class is to derive from it.
>>> class AnimalClassificationExtended(AnimalClassification):
... INVERTEBRATE = Item("Invertebrate")
>>> for item in AnimalClassificationExtended:
... print item.title
Reptile
Fish
Insect
Mammal
Invertebrate
The use_template function inserts the items from the specified enumerated type
into the new enumerated type. The default case is to take all the enumerated
items.
>>> class UIBranchType(EnumeratedType):
... use_template(BranchType)
>>> for item in UIBranchType:
... print item.title
Hosted
Mirrored
Imported
You can also specify items to be excluded by referring to the attribute name
in the exclude parameter. This can be either a string referring to one name
or a tuple or list that refers to multiple attribute names.
>>> class UIBranchType2(EnumeratedType):
... use_template(BranchType, exclude='IMPORTED')
>>> for item in UIBranchType2:
... print item.title
Hosted
Mirrored
Or limit the items to those specified:
>>> class UIBranchType3(EnumeratedType):
... use_template(BranchType, include=('HOSTED', 'MIRRORED'))
>>> for item in UIBranchType3:
... print item.title
Hosted
Mirrored
================================================
Getting from an item back to the enumerated type
================================================
Each Item in an EnumeratedType has a reference back to the EnumeratedType.
>>> print repr(apple)
<Item Fruit.APPLE, Apple>
>>> print repr(apple.enum)
<EnumeratedType 'Fruit'>
>>> for item in apple.enum:
... print item.title
Apple
Pear
Orange
============
Item.sortkey
============
The sortkey attribute of the Items are defined by the sort_order that is
defined for the enumerated type. The value is often used as a hidden value
in columns in order to ensure appropriate sorting.
>>> for item in Fruit.items:
... print item.title, item.sortkey
Apple 0
Pear 1
Orange 2
>>> for item in BranchType.items:
... print item.title, item.sortkey
Hosted 0
Mirrored 1
Imported 2
============
JSON Support
============
Enumerated types instances can be serialised to/from json. This library provides the
necessary encode and decode classes which can be used directly or as part of the
lazr.json package where they are registered as default handlers for lazr enums.
A enum instance is serialised as a dict containing:
- the enumerated type name as per the enumerated_type_registry
- the enum instance name
>>> import json
>>> from lazr.enum import EnumJSONEncoder
>>> encoded_enum = json.dumps(Fruit.APPLE, cls=EnumJSONEncoder)
>>> print encoded_enum
{"type": "Fruit", "name": "APPLE"}
To deserialse, we can specify a json object_hook as follows.
This is done transparently when using the lazr.json package.
>>> def fruit_enum_decoder(value_dict):
... return EnumJSONDecoder.from_dict(Fruit, value_dict)
>>> from lazr.enum import EnumJSONDecoder
>>> json.loads(encoded_enum, object_hook=fruit_enum_decoder)
<Item Fruit.APPLE, Apple>
==================
NEWS for lazr.enum
==================
1.1.4 (2012-04-18)
==================
- Support for serialising enums to/from json (lp:984549)
- Items which are not in an enumerator always compare as False (lp:524259)
- Fix the licence statement in _enum.py to be LGPLv3 not LGPLv3+ (lp:526484)
1.1.3 (2011-04-20)
==================
- added case insensitivity to getting the term by the token value (lp:154556)
1.1.2 (2009-08-31)
==================
- removed unnecessary build dependencies
1.1.1 (2009-08-06)
==================
- Removed sys.path hack from setup.py.
1.1 (2009-06-08)
================
- Added `url` argument to the BaseItem and DBItem constructors.
1.0 (2009-03-24)
================
- Initial release on PyPI
Platform: UNKNOWN
Classifier: Development Status :: 5 - Production/Stable
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: GNU Library or Lesser General Public License (LGPL)
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python
|