Document powerline.lint.spec.Spec object
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@ -12,6 +12,51 @@ from powerline.lint.selfcheck import havemarks
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class Spec(object):
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'''Class that describes some JSON value
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In powerline it is only used to describe JSON values stored in powerline
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configuration.
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:param dict keys:
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Dictionary that maps keys that may be present in the given JSON
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dictionary to their descriptions. If this parameter is not empty it
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implies that described value has dictionary type. Non-dictionary types
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must be described using ``Spec()``: without arguments.
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.. note::
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Methods that create the specifications return ``self``, so calls to them
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may be chained: ``Spec().type(unicode).re('^\w+$')``. This does not
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apply to functions that *apply* specification like :py:meth`Spec.match`.
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.. note::
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Methods starting with ``check_`` return two values: first determines
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whether caller should proceed on running other checks, second
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determines whether there were any problems (i.e. whether error was
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reported). One should not call these methods directly: there is
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:py:meth:`Spec.match` method for checking values.
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.. note::
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In ``check_`` and ``match`` methods specifications are identified by
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their indexes for the purpose of simplyfying :py:meth:`Spec.copy`
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method.
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Some common parameters:
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``data``:
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Whatever data supplied by the first caller for checker functions. Is not
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processed by :py:class:`Spec` methods in any fashion.
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``context``:
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:py:class:`powerline.lint.context.Context` instance, describes context
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of the value. :py:class:`Spec` methods only use its ``.key`` methods for
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error messages.
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``echoerr``:
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Callable that should be used to echo errors. Is supposed to take four
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optional keyword arguments: ``problem``, ``problem_mark``, ``context``,
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``context_mark``.
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``value``:
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Checked value.
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'''
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def __init__(self, **keys):
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self.specs = []
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self.keys = {}
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@ -24,6 +69,13 @@ class Spec(object):
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self.update(**keys)
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def update(self, **keys):
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'''Describe additional keys that may be present in given JSON value
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If called with some keyword arguments implies that described value is
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a dictionary. If called without keyword parameters it is no-op.
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:return: self.
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'''
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for k, v in keys.items():
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self.keys[k] = len(self.specs)
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self.specs.append(v)
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@ -33,6 +85,14 @@ class Spec(object):
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return self
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def copy(self, copied=None):
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'''Deep copy the spec
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:param dict copied:
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Internal dictionary used for storing already copied values. This
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parameter should not be used.
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:return: New :py:class:`Spec` object that is a deep copy of ``self``.
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'''
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copied = copied or {}
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try:
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return copied[id(self)]
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@ -42,6 +102,15 @@ class Spec(object):
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return self.__class__()._update(self.__dict__, copied)
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def _update(self, d, copied):
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'''Helper for the :py:meth:`Spec.copy` function
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Populates new instance with values taken from the old one.
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:param dict d:
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``__dict__`` of the old instance.
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:param dict copied:
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Storage for already copied values.
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'''
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self.__dict__.update(d)
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self.keys = copy(self.keys)
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self.checks = copy(self.checks)
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@ -50,6 +119,30 @@ class Spec(object):
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return self
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def unknown_spec(self, keyfunc, spec):
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'''Define specification for non-static keys
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This method should be used if key names cannot be determined at runtime
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or if a number of keys share identical spec (in order to not repeat it).
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:py:meth:`Spec.match` method processes dictionary in the given order:
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* First it tries to use specifications provided at the initialization or
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by the :py:meth:`Spec.update` method.
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* If no specification for given key was provided it processes
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specifications from ``keyfunc`` argument in order they were supplied.
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Once some key matches specification supplied second ``spec`` argument
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is used to determine correctness of the value.
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:param Spec keyfunc:
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:py:class:`Spec` instance or a regular function that returns two
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values (the same :py:meth:`Spec.match` returns). This argument is
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used to match keys that were not provided at initialization or via
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:py:meth:`Spec.update`.
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:param Spec spec:
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:py:class:`Spec` instance that will be used to check keys matched by
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``keyfunc``.
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:return: self.
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'''
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if isinstance(keyfunc, Spec):
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self.specs.append(keyfunc)
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keyfunc = len(self.specs) - 1
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@ -58,10 +151,31 @@ class Spec(object):
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return self
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def unknown_msg(self, msgfunc):
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'''Define message which will be used when unknown key was found
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“Unknown” is a key that was not provided at the initialization and via
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:py:meth:`Spec.update` and did not match any ``keyfunc`` proided via
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:py:meth:`Spec.unknown_spec`.
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:param msgfunc:
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Function that takes that unknown key as an argument and returns the
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message text. Text will appear at the top (start of the sentence).
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:return: self.
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'''
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self.ufailmsg = msgfunc
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return self
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def context_message(self, msg):
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'''Define message that describes context
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:param str msg:
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Message that describes context. Is written using the
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:py:meth:`str.format` syntax and is expected to display keyword
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parameter ``key``.
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:return: self.
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'''
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self.cmsg = msg
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for spec in self.specs:
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if not spec.cmsg:
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@ -69,6 +183,15 @@ class Spec(object):
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return self
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def check_type(self, value, context_mark, data, context, echoerr, types):
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'''Check that given value matches given type(s)
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:param tuple types:
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List of accepted types. Since :py:class:`Spec` is supposed to
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describe JSON values only ``dict``, ``list``, ``unicode``, ``bool``,
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``float`` and ``NoneType`` types make any sense.
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:return: proceed, hadproblem.
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'''
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havemarks(value)
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if type(value.value) not in types:
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echoerr(
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@ -85,6 +208,34 @@ class Spec(object):
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return True, False
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def check_func(self, value, context_mark, data, context, echoerr, func, msg_func):
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'''Check value using given function
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:param function func:
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Callable that should accept four positional parameters:
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#. checked value,
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#. ``data`` parameter with arbitrary data (supplied by top-level
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caller),
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#. current context and
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#. function used for echoing errors.
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This callable should return three values:
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#. determines whether ``check_func`` caller should proceed
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calling other checks,
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#. determines whether ``check_func`` should echo error on its own
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(it should be set to False if ``func`` echoes error itself) and
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#. determines whether function has found some errors in the checked
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value.
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:param function msg_func:
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Callable that takes checked value as the only positional parameter
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and returns a string that describes the problem. Only useful for
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small checker functions since it is ignored when second returned
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value is false.
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:return: proceed, hadproblem.
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'''
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havemarks(value)
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proceed, echo, hadproblem = func(value, data, context, echoerr)
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if echo and hadproblem:
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@ -95,6 +246,19 @@ class Spec(object):
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return proceed, hadproblem
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def check_list(self, value, context_mark, data, context, echoerr, item_func, msg_func):
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'''Check that each value in the list matches given specification
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:param function item_func:
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Callable like ``func`` from :py:meth:`Spec.check_func`. Unlike
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``func`` this callable is called for each value in the list and may
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be a :py:class:`Spec` object index.
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:param func msg_func:
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Callable like ``msg_func`` from :py:meth:`Spec.check_func`. Should
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accept one problematic item and is not used for :py:class:`Spec`
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object indicies in ``item_func`` method.
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:return: proceed, hadproblem.
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'''
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havemarks(value)
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i = 0
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hadproblem = False
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@ -124,6 +288,17 @@ class Spec(object):
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return True, hadproblem
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def check_either(self, value, context_mark, data, context, echoerr, start, end):
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'''Check that given value matches one of the given specifications
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:param int start:
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First specification index.
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:param int end:
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Specification index that is greater by 1 then last specification
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index.
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This method does not give an error if any specification from
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``self.specs[start:end]`` is matched by the given value.
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'''
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havemarks(value)
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new_echoerr = DelayedEchoErr(echoerr)
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@ -140,6 +315,17 @@ class Spec(object):
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return False, hadproblem
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def check_tuple(self, value, context_mark, data, context, echoerr, start, end):
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'''Check that given value is a list with items matching specifications
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:param int start:
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First specification index.
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:param int end:
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Specification index that is greater by 1 then last specification
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index.
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This method checks that each item in the value list matches
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specification with index ``start + item_number``.
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'''
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havemarks(value)
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hadproblem = False
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for (i, item, spec) in zip(itertools.count(), value, self.specs[start:end]):
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return True, hadproblem
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def type(self, *args):
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'''Describe value that has one of the types given in arguments
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:param args:
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List of accepted types. Since :py:class:`Spec` is supposed to
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describe JSON values only ``dict``, ``list``, ``unicode``, ``bool``,
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``float`` and ``NoneType`` types make any sense.
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:return: self.
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'''
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self.checks.append(('check_type', args))
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return self
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@ -177,6 +372,20 @@ class Spec(object):
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}
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def len(self, comparison, cint, msg_func=None):
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'''Describe value that has given length
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:param str comparison:
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Type of the comparison. Valid values: ``le``, ``lt``, ``ge``,
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``gt``, ``eq``.
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:param int cint:
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Integer with which length is compared.
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:param function msg_func:
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Function that should accept checked value and return message that
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describes the problem with this value. Default value will emit
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something like “length of ["foo", "bar"] is not greater then 10”.
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:return: self.
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'''
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cmp_func = self.cmp_funcs[comparison]
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msg_func = (
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msg_func
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return self
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def cmp(self, comparison, cint, msg_func=None):
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'''Describe value that is a number or string that has given property
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:param str comparison:
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Type of the comparison. Valid values: ``le``, ``lt``, ``ge``,
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``gt``, ``eq``. This argument will restrict the number or string to
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emit True on the given comparison.
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:param cint:
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Number or string with which value is compared. Type of this
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parameter affects required type of the checked value: ``str`` and
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``unicode`` types imply ``unicode`` values, ``float`` type implies
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that value can be either ``int`` or ``float``, ``int`` type implies
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``int`` value and for any other type the behavior is undefined.
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:param function msg_func:
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Function that should accept checked value and return message that
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describes the problem with this value. Default value will emit
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something like “10 is not greater then 10”.
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:return: self.
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'''
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if type(cint) is str:
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self.type(unicode)
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elif type(cint) is float:
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@ -207,6 +435,14 @@ class Spec(object):
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return self
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def unsigned(self, msg_func=None):
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'''Describe unsigned integer value
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:param function msg_func:
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Function that should accept checked value and return message that
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describes the problem with this value.
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:return: self.
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'''
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self.type(int)
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self.checks.append((
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'check_func',
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@ -216,6 +452,20 @@ class Spec(object):
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return self
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def list(self, item_func, msg_func=None):
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'''Describe list with any number of elements, each matching given spec
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:param item_func:
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:py:class:`Spec` instance or a callable. Check out
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:py:meth:`Spec.check_list` documentation for more details. Note that
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in :py:meth:`Spec.check_list` description :py:class:`Spec` instance
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is replaced with its index in ``self.specs``.
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:param function msg_func:
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Function that should accept checked value and return message that
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describes the problem with this value. Default value will emit just
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“failed check”, which is rather indescriptive.
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:return: self.
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'''
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self.type(list)
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if isinstance(item_func, Spec):
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self.specs.append(item_func)
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return self
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def tuple(self, *specs):
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'''Describe list with the given number of elements, each matching corresponding spec
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:param (Spec,) specs:
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List of specifications. Last element(s) in this list may be
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optional. Each element in this list describes element with the same
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index in the checked value. Check out :py:meth:`Spec.check_tuple`
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for more details, but note that there list of specifications is
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replaced with start and end indicies in ``self.specs``.
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:return: self.
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'''
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self.type(list)
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max_len = len(specs)
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@ -246,10 +507,25 @@ class Spec(object):
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return self
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def func(self, func, msg_func=None):
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'''Describe value that is checked by the given function
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Check out :py:meth:`Spec.check_func` documentation for more details.
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'''
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self.checks.append(('check_func', func, msg_func or (lambda value: 'failed check')))
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return self
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def re(self, regex, msg_func=None):
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'''Describe value that is a string that matches given regular expression
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:param str regex:
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Regular expression that should be matched by the value.
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:param function msg_func:
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Function that should accept checked value and return message that
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describes the problem with this value. Default value will emit
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something like “String "xyz" does not match "[a-f]+"”.
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:return: self.
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'''
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self.type(unicode)
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compiled = re.compile(regex)
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msg_func = msg_func or (lambda value: 'String "{0}" does not match "{1}"'.format(value, regex))
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return self
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def ident(self, msg_func=None):
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'''Describe value that is an identifier like ``foo:bar`` or ``foo``
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:param function msg_func:
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Function that should accept checked value and return message that
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describes the problem with this value. Default value will emit
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something like “String "xyz" is not an … identifier”.
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:return: self.
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'''
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msg_func = (
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msg_func
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or (lambda value: 'String "{0}" is not an alphanumeric/underscore colon-separated identifier'.format(value))
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@ -268,6 +553,17 @@ class Spec(object):
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return self.re('^\w+(?::\w+)?$', msg_func)
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def oneof(self, collection, msg_func=None):
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'''Describe value that is equal to one of the value in the collection
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:param set collection:
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A collection of possible values.
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:param function msg_func:
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Function that should accept checked value and return message that
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describes the problem with this value. Default value will emit
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something like “"xyz" must be one of {"abc", "def", "ghi"}”.
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:return: self.
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'''
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msg_func = msg_func or (lambda value: '"{0}" must be one of {1!r}'.format(value, list(collection)))
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self.checks.append((
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'check_func',
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@ -277,6 +573,19 @@ class Spec(object):
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return self
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def error(self, msg):
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'''Describe value that must not be there
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Useful for giving more descriptive errors for some specific keys then
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just “found unknown key: shutdown_event” or for forbidding certain
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values when :py:meth:`Spec.unknown_spec` was used.
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:param str msg:
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Message given for the offending value. It is formatted using
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:py:meth:`str.format` with the only positional parameter which is
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the value itself.
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:return: self.
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'''
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self.checks.append((
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'check_func',
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(lambda *args: (True, True, True)),
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@ -285,20 +594,54 @@ class Spec(object):
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return self
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def either(self, *specs):
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'''Describes value that matches one of the given specs
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Check out :py:meth:`Spec.check_either` method documentation for more
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details, but note that there a list of specs was replaced by start and
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end indicies in ``self.specs``.
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:return: self.
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'''
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start = len(self.specs)
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self.specs.extend(specs)
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self.checks.append(('check_either', start, len(self.specs)))
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return self
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def optional(self):
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'''Mark value as optional
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Only useful for key specs in :py:meth:`Spec.__init__` and
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:py:meth:`Spec.update` and some last supplied to :py:meth:`Spec.tuple`.
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:return: self.
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'''
|
||||
self.isoptional = True
|
||||
return self
|
||||
|
||||
def required(self):
|
||||
'''Mark value as required
|
||||
|
||||
Only useful for key specs in :py:meth:`Spec.__init__` and
|
||||
:py:meth:`Spec.update` and some last supplied to :py:meth:`Spec.tuple`.
|
||||
|
||||
.. note::
|
||||
Value is required by default. This method is only useful for
|
||||
altering existing specification (or rather its copy).
|
||||
|
||||
:return: self.
|
||||
'''
|
||||
self.isoptional = False
|
||||
return self
|
||||
|
||||
def match_checks(self, *args):
|
||||
'''Process checks registered for the given value
|
||||
|
||||
Processes only “top-level” checks: key specifications given using at the
|
||||
initialization or via :py:meth:`Spec.unknown_spec` are processed by
|
||||
:py:meth:`Spec.match`.
|
||||
|
||||
:return: proceed, hadproblem.
|
||||
'''
|
||||
hadproblem = False
|
||||
for check in self.checks:
|
||||
proceed, chadproblem = getattr(self, check[0])(*(args + check[1:]))
|
||||
|
@ -309,6 +652,10 @@ class Spec(object):
|
|||
return True, hadproblem
|
||||
|
||||
def match(self, value, context_mark=None, data=None, context=(), echoerr=echoerr):
|
||||
'''Check that given value matches this specification
|
||||
|
||||
:return: proceed, hadproblem.
|
||||
'''
|
||||
havemarks(value)
|
||||
proceed, hadproblem = self.match_checks(value, context_mark, data, context, echoerr)
|
||||
if proceed:
|
||||
|
@ -367,7 +714,11 @@ class Spec(object):
|
|||
return True, hadproblem
|
||||
|
||||
def __getitem__(self, key):
|
||||
'''Get specification for the given key
|
||||
'''
|
||||
return self.specs[self.keys[key]]
|
||||
|
||||
def __setitem__(self, key, value):
|
||||
return self.update(**{key: value})
|
||||
'''Set specification for the given key
|
||||
'''
|
||||
self.update(**{key: value})
|
||||
|
|
Loading…
Reference in New Issue