1 """The `command` module provides :class:`Command`\s and
2 :class:`Argument`\s for defining commands.
11 class CommandExit (Exception):
14 class Success (CommandExit):
18 """The command requests an end to the interpreter session.
22 class Failure (CommandExit):
25 class UncaughtException (Failure):
26 def __init__(self, exception, traceback_string=None):
27 super(UncaughtException, self).__init__()
28 if traceback_string == None:
29 traceback_string = traceback.format_exc()
31 self.exception = exception
32 self.traceback = traceback_string
33 self.__setstate__(self.__getstate__())
35 def __getstate__(self):
36 """Return a picklable representation of the objects state.
38 :mod:`pickle`'s doesn't call a :meth:`__init__` when
39 rebuilding a class instance. To preserve :attr:`args` through
40 a pickle cycle, we use :meth:`__getstate__` and
43 See `pickling class instances`_ and `pickling examples`_.
45 .. _pickling class instances:
46 http://docs.python.org/library/pickle.html#pickling-and-unpickling-normal-class-instances
47 .. _pickling examples:
48 http://docs.python.org/library/pickle.html#example
50 return {'exception':self.exception, 'traceback':self.traceback}
52 def __setstate__(self, state):
53 """Apply the picklable state from :meth:`__getstate__` to
54 reconstruct the instance.
56 for key,value in state.items():
57 setattr(self, key, value)
58 self.args = (self.traceback + str(self.exception),)
61 """:class:`Request` validator class.
66 >>> i = InList(['abc', 'def', 5, True])
70 Traceback (most recent call last):
74 def __init__(self, *args, **kwargs):
75 list.__init__(self, *args, **kwargs)
77 def __call__(self, value):
78 """Raises ValueError if a given `value` is not in our internal
82 raise ValueError(value)
84 class Interaction (object):
85 """Mid-command inter-process interaction.
87 Stores :attr:`type`, a string representing the interaction type
88 ('boolean', 'string', ...).
90 def __init__(self, type):
93 class Request (Interaction):
94 """Command engine requests for information from the UI.
96 def __init__(self, type, response_class,
97 msg, default=None, validator=None):
98 super(Request, self).__init__(type)
99 self.response_class = response_class
101 self.default = default
102 self.validator = validator
104 def response(self, value):
105 if self.validator != None:
106 self.validator(value)
107 return self.response_class(value)
109 class Response (Interaction):
110 """UI response to a :class:`Request`.
112 def __init__(self, type, value):
113 super(Response, self).__init__(type)
116 class BooleanRequest (Request):
117 def __init__(self, msg, default=None):
118 super(BooleanRequest, self).__init__(
119 'boolean', BooleanResponse, msg, default,
120 validator = InList([True, False, default]))
122 class BooleanResponse (Response):
123 def __init__(self, value):
124 super(BooleanResponse, self).__init__('boolean', value)
126 class StringRequest (Request):
127 def __init__(self, msg, default=None):
128 super(StringRequest, self).__init__(
129 'string', StringResponse, msg, default)
131 class StringResponse (Response):
132 def __init__(self, value):
133 super(StringResponse, self).__init__('string', value)
135 class FloatRequest (Request):
136 def __init__(self, msg, default=None):
137 super(FloatRequest, self).__init__(
138 'float', FloatResponse, msg, default)
140 class FloatResponse (Response):
141 def __init__(self, value):
142 super(FloatResponse, self).__init__('float', value)
144 class SelectionRequest (Request):
145 def __init__(self, msg, default=None, options=[]):
146 super(SelectionRequest, self).__init__(
147 'selection', SelectionResponse, msg, default)
148 self.options = options
150 class SelectionResponse (Response):
151 def __init__(self, value):
152 super(SelectionResponse, self).__init__('selection', value)
155 class Command (object):
156 """One-line command description here.
158 >>> c = Command(name='test', help='An example Command.')
160 >>> status = c.run(hooke, NullQueue(), PrintQueue(),
161 ... help=True) # doctest: +REPORT_UDIFF
167 help BOOL (bool) Print a help message.
173 def __init__(self, name, aliases=None, arguments=[], help=''):
177 self.aliases = aliases
179 Argument(name='help', type='bool', default=False, count=1,
180 callback=StoreValue(True), help='Print a help message.'),
184 def run(self, hooke, inqueue=None, outqueue=None, **kwargs):
185 """`Normalize inputs and handle <Argument help> before punting
189 inqueue = NullQueue()
191 outqueue = NullQueue()
193 params = self.handle_arguments(hooke, inqueue, outqueue, kwargs)
194 if params['help'] == True:
195 outqueue.put(self.help())
197 self._run(hooke, inqueue, outqueue, params)
198 except CommandExit, e:
199 if isinstance(e, Failure):
202 # other CommandExit subclasses fall through to the end
204 x = UncaughtException(e)
212 def _run(self, inqueue, outqueue, params):
213 """This is where the command-specific magic will happen.
217 def handle_arguments(self, hooke, inqueue, outqueue, params):
218 """Normalize and validate input parameters (:class:`Argument` values).
220 for argument in self.arguments:
221 names = [argument.name] + argument.aliases
222 settings = [(name,v) for name,v in params.items() if name in names]
223 num_provided = len(settings)
224 if num_provided == 0:
225 if argument.optional == True or argument.count == 0:
226 settings = [(argument.name, argument.default)]
228 raise Failure('Required argument %s not set.'
231 raise Failure('Multiple settings for %s:\n %s'
233 '\n '.join(['%s: %s' % (name,value)
234 for name,value in sorted(settings)])))
235 name,value = settings[0]
236 if num_provided == 0:
237 params[argument.name] = value
239 if name != argument.name:
241 params[argument.name] = value
242 if argument.callback != None:
243 value = argument.callback(hooke, self, argument, value)
244 params[argument.name] = value
245 argument.validate(value)
248 def help(self, name_fn=lambda name:name):
249 """Return a help message describing the `Command`.
251 `name_fn(internal_name) -> external_name` gives calling
252 :class:`hooke.ui.UserInterface`\s a means of changing the
253 display names if it wants (e.g. to remove spaces from command
256 name_part = 'Command: %s' % name_fn(self.name)
257 if len(self.aliases) > 0:
258 name_part += ' (%s)' % ', '.join(
259 [name_fn(n) for n in self.aliases])
261 if len(self.arguments) > 0:
262 argument_part = ['Arguments:', '']
263 for a in self.arguments:
264 argument_part.append(textwrap.fill(
267 subsequent_indent=" "))
268 argument_part = '\n'.join(argument_part)
269 parts.append(argument_part)
270 parts.append(self._help) # help part
271 return '\n\n'.join(parts)
273 class Argument (object):
274 """Structured user input for :class:`Command`\s.
276 TODO: ranges for `count`?
278 def __init__(self, name, aliases=None, type='string', metavar=None,
279 default=None, optional=True, count=1,
280 completion_callback=None, callback=None, help=''):
284 self.aliases = aliases
287 metavar = type.upper()
288 self.metavar = metavar
289 self.default = default
290 self.optional = optional
292 self.completion_callback = completion_callback
293 self.callback = callback
297 return '<%s %s>' % (self.__class__.__name__, self.name)
300 return self.__str__()
302 def help(self, name_fn=lambda name:name):
303 """Return a help message describing the `Argument`.
305 `name_fn(internal_name) -> external_name` gives calling
306 :class:`hooke.ui.UserInterface`\s a means of changing the
307 display names if it wants (e.g. to remove spaces from command
310 parts = ['%s ' % name_fn(self.name)]
311 if self.metavar != None:
312 parts.append('%s ' % self.metavar)
313 parts.extend(['(%s) ' % self.type, self._help])
314 return ''.join(parts)
316 def validate(self, value):
317 """If `value` is not appropriate, raise `ValueError`.
319 pass # TODO: validation
321 # TODO: type conversion
323 # TODO: type extensions?
327 class StoreValue (object):
328 def __init__(self, value):
330 def __call__(self, hooke, command, argument, fragment=None):
333 class NullQueue (queue.Queue):
334 """The :class:`queue.Queue` equivalent of `/dev/null`.
336 This is a bottomless pit. Items go in, but never come out.
338 def get(self, block=True, timeout=None):
339 """Raise queue.Empty.
341 There's really no need to override the base Queue.get, but I
342 want to know if someone tries to read from a NullQueue. With
343 the default implementation they would just block silently
348 def put(self, item, block=True, timeout=None):
349 """Dump an item into the void.
351 Block and timeout are meaningless, because there is always a
352 free slot available in a bottomless pit.
356 class PrintQueue (NullQueue):
357 """Debugging :class:`NullQueue` that prints items before dropping
360 def put(self, item, block=True, timeout=None):
361 """Print `item` and then dump it into the void.
363 print 'ITEM:\n%s' % item