src/booleano/operations/converters.py
# -*- coding: utf-8 -*-
# Copyright (c) 2009 by Gustavo Narea <http://gustavonarea.net/>.
# This file is part of Booleano <http://code.gustavonarea.net/booleano/>.
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, distribute with
# modifications, sublicense, and/or sell copies of the Software, and to permit
# persons to whom the Software is furnished to do so, subject to the following
# conditions:
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
# IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
# Except as contained in this notice, the name(s) of the above copyright
# holders shall not be used in advertising or otherwise to promote the sale,
# use or other dealings in this Software without prior written authorization.
"""
Converters for Booleano parse tree structures (the convertible, not the
evaluable ones).
"""
from __future__ import unicode_literals
from booleano.exc import ConversionError
from booleano.operations.operands.constants import Number, Set, String
from booleano.operations.operands.placeholders import PlaceholderFunction, PlaceholderVariable
from booleano.operations.operators import (And, BelongsTo, Equal, GreaterEqual, GreaterThan, IsSubset, LessEqual,
LessThan, Not, NotEqual, Or, UnaryOperator, Xor)
__all__ = ("BaseConverter", )
class BaseConverter(object):
"""
The base class for converters.
All the methods of this class are abstract, except for :meth:`__call__`
and :meth:`convert`.
"""
__converters__ = {
# Operation converters:
Not: "convert_not",
And: "convert_and",
Or: "convert_or",
Xor: "convert_xor",
Equal: "convert_equal",
NotEqual: "convert_not_equal",
LessThan: "convert_less_than",
GreaterThan: "convert_greater_than",
LessEqual: "convert_less_equal",
GreaterEqual: "convert_greater_equal",
BelongsTo: "convert_belongs_to",
IsSubset: "convert_is_subset",
# Operand converters:
String: "convert_string",
Number: "convert_number",
Set: "convert_set",
PlaceholderVariable: "convert_variable",
PlaceholderFunction: "convert_function",
}
def __call__(self, root_node):
"""
Convert ``root_node``.
:param root_node: The root of the tree to be converted.
:type root_node: :class:`booleano.operations.core.OperationNode`
:return: The tree converted.
:raises booleano.exc.ConversionError: If the type of ``root_node`` is
unknown.
If ``node`` is a branch, its children will be converted first.
"""
root_node_type = root_node.__class__
if root_node_type not in self.__converters__:
raise ConversionError("Unknown tree node type: %s" % root_node_type)
return self.convert(root_node)
def convert(self, node):
"""
Convert ``node``.
:param node: The node to be converted.
:type node: :class:`booleano.operations.core.OperationNode`
:return: The node converted.
If ``node`` is a branch, its children will be converted first.
This is the method in charge of calling the right conversion method for
the type of ``node`` and **it should not be called directly** (use
:meth:`__call__` instead).
"""
convert = getattr(self, self.__converters__[node.__class__])
if node.is_leaf():
if isinstance(node, PlaceholderVariable):
return convert(node.name, node.namespace_parts)
# It's a string or a number
return convert(node.constant_value)
if isinstance(node, Set):
elements = [self.convert(element) for element
in node.constant_value]
return convert(*elements)
if isinstance(node, PlaceholderFunction):
arguments = [self.convert(arg) for arg in node.arguments]
return convert(node.name, node.namespace_parts, *arguments)
# At this point, node must be an operator.
if isinstance(node, UnaryOperator):
operand = self.convert(node.operand)
return convert(operand)
# It's a binary operator!
master_operand = self.convert(node.master_operand)
slave_operand = self.convert(node.slave_operand)
return convert(master_operand, slave_operand)
# Operation converters
def convert_not(self, operand):
"""
Convert negation function whose argument is ``operand``.
:param operand: The argument already converted.
:type operand: :class:`object`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_and(self, master_operand, slave_operand):
"""
Convert AND connective whose left-hand operand is ``master_operand``
and right-hand operand is ``slave_operand``.
:param master_operand: The left-hand operand, already converted.
:type master_operand: :class:`object`
:param slave_operand: The right-hand operand, already converted.
:type slave_operand: :class:`object`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_or(self, master_operand, slave_operand):
"""
Convert OR connective whose left-hand operand is ``master_operand``
and right-hand operand is ``slave_operand``.
:param master_operand: The left-hand operand, already converted.
:type master_operand: :class:`object`
:param slave_operand: The right-hand operand, already converted.
:type slave_operand: :class:`object`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_xor(self, master_operand, slave_operand):
"""
Convert XOR connective whose left-hand operand is ``master_operand``
and right-hand operand is ``slave_operand``.
:param master_operand: The left-hand operand, already converted.
:type master_operand: :class:`object`
:param slave_operand: The right-hand operand, already converted.
:type slave_operand: :class:`object`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_equal(self, master_operand, slave_operand):
"""
Convert equality operation whose left-hand operand is ``master_operand``
and right-hand operand is ``slave_operand``.
:param master_operand: The left-hand operand, already converted.
:type master_operand: :class:`object`
:param slave_operand: The right-hand operand, already converted.
:type slave_operand: :class:`object`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_not_equal(self, master_operand, slave_operand):
"""
Convert "not equal to" operation whose left-hand operand is
``master_operand`` and right-hand operand is ``slave_operand``.
:param master_operand: The left-hand operand, already converted.
:type master_operand: :class:`object`
:param slave_operand: The right-hand operand, already converted.
:type slave_operand: :class:`object`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_less_than(self, master_operand, slave_operand):
"""
Convert "less than" operation whose left-hand operand is
``master_operand`` and right-hand operand is ``slave_operand``.
:param master_operand: The left-hand operand, already converted.
:type master_operand: :class:`object`
:param slave_operand: The right-hand operand, already converted.
:type slave_operand: :class:`object`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_greater_than(self, master_operand, slave_operand):
"""
Convert "greater than" operation whose left-hand operand is
``master_operand`` and right-hand operand is ``slave_operand``.
:param master_operand: The left-hand operand, already converted.
:type master_operand: :class:`object`
:param slave_operand: The right-hand operand, already converted.
:type slave_operand: :class:`object`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_less_equal(self, master_operand, slave_operand):
"""
Convert "less than or equal to" operation whose left-hand operand is
``master_operand`` and right-hand operand is ``slave_operand``.
:param master_operand: The left-hand operand, already converted.
:type master_operand: :class:`object`
:param slave_operand: The right-hand operand, already converted.
:type slave_operand: :class:`object`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_greater_equal(self, master_operand, slave_operand):
"""
Convert "greater than or equal to" operation whose left-hand operand is
``master_operand`` and right-hand operand is ``slave_operand``.
:param master_operand: The left-hand operand, already converted.
:type master_operand: :class:`object`
:param slave_operand: The right-hand operand, already converted.
:type slave_operand: :class:`object`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_belongs_to(self, master_operand, slave_operand):
"""
Convert "belongs to" operation where the set is
``master_operand`` and the element is ``slave_operand``.
:param master_operand: The set already converted.
:type master_operand: :class:`object`
:param slave_operand: The element already converted.
:type slave_operand: :class:`object`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_is_subset(self, master_operand, slave_operand):
"""
Convert "is subset of" operation where the superset is
``master_operand`` and the subset is ``slave_operand``.
:param master_operand: The superset already converted.
:type master_operand: :class:`object`
:param slave_operand: The subset already converted.
:type slave_operand: :class:`object`
:rtype: :class:`object`
"""
raise NotImplementedError
# Operand converters
def convert_string(self, text):
"""
Convert the literal string ``text``.
:param text: The contents of the literal string.
:type text: :class:`basestring`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_number(self, number):
"""
Convert the literal number ``number``.
:param number: The literal number.
:type number: :class:`float`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_set(self, *elements):
"""
Convert the literal set with the ``elements``.
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_variable(self, name, namespace_parts):
"""
Convert the variable called ``name``.
:param name: The name of the variable.
:type name: :class:`basestring`
:param namespace_parts: The namespace of the variable (if any),
represented by the identifiers that make it up.
:type namespace_parts: :class:`list`
:rtype: :class:`object`
"""
raise NotImplementedError
def convert_function(self, name, namespace_parts, *arguments):
"""
Convert the function call to ``name`` using the additional positional
arguments as the arguments of the call.
:param name: The name of the function being called.
:type name: :class:`basestring`
:param namespace_parts: The namespace of the function (if any),
represented by the identifiers that make it up.
:type namespace_parts: :class:`list`
:rtype: :class:`object`
The arguments will be received converted.
"""
raise NotImplementedError
#