Source code for dragonfly.grammar.rule_mapping

#
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# (c) Copyright 2007, 2008 by Christo Butcher
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"""
MappingRule class
============================================================================

The MappingRule class is designed to make it very easy to create a rule 
based on a mapping of spoken-forms to semantic values.

This class has the following parameters to customize its behavior:

 - *mapping* -- mapping of spoken-forms to semantic values
 - *extras* -- extras elements referenced from the compound spec
 - *defaults* -- default values for the extras
 - *exported* -- whether the rule is exported
 - *context* -- context in which the rule will be active

Each of these parameters can be passed as a (keyword) arguments to the 
constructor, or defined as a class attribute in a derived class.


Example usage
............................................................................

The MappingRule class can be used to define a voice-command as follows::

    class ExampleRule(MappingRule):

        mapping  = {
                    "[feed] address [bar]":                Key("a-d"),
                    "subscribe [[to] [this] feed]":        Key("a-u"),
                    "paste [feed] address":                Key("a-d, c-v, enter"),
                    "feeds | feed (list | window | win)":  Key("a-d, tab:2, s-tab"),
                    "down [<n>] (feed | feeds)":           Key("a-d, tab:2, s-tab, down:%(n)d"),
                    "up [<n>] (feed | feeds)":             Key("a-d, tab:2, s-tab, up:%(n)d"),
                    "open [item]":                         Key("a-d, tab:2, c-s"),
                    "newer [<n>]":                         Key("a-d, tab:2, up:%(n)d"),
                    "older [<n>]":                         Key("a-d, tab:2, down:%(n)d"),
                    "mark all [as] read":                  Key("cs-r"),
                    "mark all [as] unread":                Key("cs-u"),
                    "search [bar]":                        Key("a-s"),
                    "search [for] <text>":                 Key("a-s") + Text("%(text)s\\n"),
                   }
        extras   = [
                    Integer("n", 1, 20),
                    Dictation("text"),
                   ]
        defaults = {
                    "n": 1,
                   }

        rule = ExampleRule()
        grammar.add_rule(rule)


Class reference
............................................................................

"""

from .rule_base         import Rule
from .elements          import ElementBase, Compound, Alternative
from ..actions.actions  import ActionBase


#---------------------------------------------------------------------------

[docs]class MappingRule(Rule): """ Rule class based on a mapping of spoken-forms to semantic values. Constructor arguments: - *name* (*str*) -- the rule's name - *mapping* (*dict*) -- mapping of spoken-forms to semantic values - *extras* (sequence) -- extras elements referenced from the spoken-forms in *mapping* - *defaults* (*dict*) -- default values for the extras - *exported* (boolean) -- whether the rule is exported - *context* (*Context*) -- context in which the rule will be active """ mapping = {} extras = [] defaults = {} context = None _default_exported = True #----------------------------------------------------------------------- def __init__(self, name=None, mapping=None, extras=None, defaults=None, exported=None, context=None): if name is None: name = self.__class__.__name__ if mapping is None: mapping = self.mapping if extras is None: extras = self.extras if defaults is None: defaults = self.defaults if context is None: context = self.context # Complex handling of exported, because of clashing use of the # exported name at the class level: property & class-value. if exported is not None: pass elif (hasattr(self.__class__, "exported") and not isinstance(self.__class__.exported, property)): exported = self.__class__.exported else: exported = self._default_exported # Type checking of initialization values. assert isinstance(name, (str, unicode)) assert isinstance(mapping, dict) for key, value in mapping.iteritems(): assert isinstance(key, (str, unicode)) assert isinstance(extras, (list, tuple)) for item in extras: assert isinstance(item, ElementBase) assert exported == True or exported == False self._name = name self._mapping = mapping self._extras = dict([(element.name, element) for element in extras]) self._defaults = defaults children = [] for spec, value in self._mapping.iteritems(): c = Compound(spec, elements=self._extras, value=value) children.append(c) if children: element = Alternative(children) else: element = None Rule.__init__(self, self._name, element, exported=exported, context=context) #----------------------------------------------------------------------- def value(self, node): node = node.children[0] value = node.value() if hasattr(value, "copy_bind"): # Prepare *extras* dict for passing to _copy_bind(). extras = { "_grammar": self.grammar, "_rule": self, "_node": node, } extras.update(self._defaults) for name, element in self._extras.iteritems(): extra_node = node.get_child_by_name(name, shallow=True) if extra_node: extras[name] = extra_node.value() elif element.has_default(): extras[name] = element.default value = value.copy_bind(extras) return value
[docs] def process_recognition(self, node): """ Process a recognition of this rule. This method is called by the containing Grammar when this rule is recognized. This method collects information about the recognition and then calls MappingRule._process_recognition. - *node* -- The root node of the recognition parse tree. """ item_value = node.value() # Prepare *extras* dict for passing to _process_recognition(). extras = { "_grammar": self.grammar, "_rule": self, "_node": node, } extras.update(self._defaults) for name, element in self._extras.iteritems(): extra_node = node.get_child_by_name(name, shallow=True) if extra_node: extras[name] = extra_node.value() elif element.has_default(): extras[name] = element.default # Call the method to do the actual processing. self._process_recognition(item_value, extras)
def _process_recognition(self, value, extras): """ Default recognition processing. This is the method which should be overridden in most cases to provide derived classes with custom recognition processing functionality. This default processing method takes the mapping value from the recognition and, if it is an action, executes it with the given extras as a dynamic values. - *value* -- The mapping value recognized. - *extras* -- A dictionary of all elements from the extras list contained within this recognition. Maps element name -> element value. """ if isinstance(value, ActionBase): value.execute(extras) elif self._log_proc: self._log_proc.warning("%s: mapping value is not an action," " cannot execute." % self)