1# Copyright 2020, 2021 PaGMO development team
2#
3# This file is part of the pygmo library.
4#
5# This Source Code Form is subject to the terms of the Mozilla
6# Public License v. 2.0. If a copy of the MPL was not distributed
7# with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
8
9from .core import algorithm
10
11
12def _algorithm_extract(self, t):
13    """Extract the user-defined algorithm.
14
15    This method allows to extract a reference to the user-defined algorithm (UDA) stored within this
16    :class:`~pygmo.algorithm` instance. The behaviour of this function depends on the value
17    of *t* (which must be a :class:`type`) and on the type of the internal UDA:
18
19    * if the type of the UDA is *t*, then a reference to the UDA will be returned
20      (this mirrors the behaviour of the corresponding C++ method
21      :cpp:func:`pagmo::algorithm::extract()`),
22    * if *t* is :class:`object` and the UDA is a Python object (as opposed to an
23      :ref:`exposed C++ algorithm <algorithms_cpp>`), then a reference to the
24      UDA will be returned (this allows to extract a Python UDA without knowing its type),
25    * otherwise, :data:`None` will be returned.
26
27    Args:
28        t (:class:`type`): the type of the user-defined algorithm to extract
29
30    Returns:
31        a reference to the internal user-defined algorithm, or :data:`None` if the extraction fails
32
33    Raises:
34        TypeError: if *t* is not a :class:`type`
35
36    Examples:
37        >>> import pygmo as pg
38        >>> a1 = pg.algorithm(pg.compass_search())
39        >>> a1.extract(pg.compass_search) # doctest: +SKIP
40        <pygmo.core.compass_search at 0x7f8e4792b670>
41        >>> a1.extract(pg.de) is None
42        True
43        >>> class algo:
44        ...     def evolve(self, pop):
45        ...         return pop
46        >>> a2 = pg.algorithm(algo())
47        >>> a2.extract(object) # doctest: +SKIP
48        <__main__.algo at 0x7f8e478c04e0>
49        >>> a2.extract(algo) # doctest: +SKIP
50        <__main__.algo at 0x7f8e478c04e0>
51        >>> a2.extract(pg.de) is None
52        True
53
54    """
55    if not isinstance(t, type):
56        raise TypeError("the 't' parameter must be a type")
57    if hasattr(t, "_pygmo_cpp_algorithm"):
58        return self._cpp_extract(t())
59    return self._py_extract(t)
60
61
62def _algorithm_is(self, t):
63    """Check the type of the user-defined algorithm.
64
65    This method returns :data:`False` if :func:`extract(t) <pygmo.algorithm.extract>` returns
66    :data:`None`, and :data:`True` otherwise.
67
68    Args:
69        t (:class:`type`): the type that will be compared to the type of the UDA
70
71    Returns:
72        bool: whether the UDA is of type *t* or not
73
74    Raises:
75        unspecified: any exception thrown by :func:`~pygmo.algorithm.extract()`
76
77    """
78    return not self.extract(t) is None
79
80
81# Do the actual patching.
82setattr(algorithm, "extract", _algorithm_extract)
83setattr(algorithm, "is_", _algorithm_is)
84