.. index:: single: metap
.. _metap/0:

.. rst-class:: right

**protocol**

``metap``
=========

Useful meta-predicates protocol.

| **Availability:** 
|    ``logtalk_load(meta(loader))``

| **Author:** Paulo Moura
| **Version:** 6:1:0
| **Date:** 2015-12-23

| **Compilation flags:**
|    ``static``


| **Dependencies:**
|   (none)


| **Remarks:**
|    (none)

| **Inherited public predicates:**
|    (none)

.. contents::
   :local:
   :backlinks: top

Public predicates
-----------------

.. index:: include/3
.. _metap/0::include/3:

``include/3``
^^^^^^^^^^^^^

Returns a list of all list elements that satisfy a predicate.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``include(Closure,List,Included)``
| **Meta-predicate template:**
|    ``include(1,*,*)``
| **Mode and number of proofs:**
|    ``include(+callable,+list,-list)`` - ``one``


------------

.. index:: exclude/3
.. _metap/0::exclude/3:

``exclude/3``
^^^^^^^^^^^^^

Returns a list of all list elements that fail to satisfy a predicate.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``exclude(Closure,List,Excluded)``
| **Meta-predicate template:**
|    ``exclude(1,*,*)``
| **Mode and number of proofs:**
|    ``exclude(+callable,+list,-list)`` - ``one``


------------

.. index:: findall_member/4
.. _metap/0::findall_member/4:

``findall_member/4``
^^^^^^^^^^^^^^^^^^^^

Finds all members of a list that satisfy a given test.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``findall_member(Member,List,Test,Result)``
| **Meta-predicate template:**
|    ``findall_member(*,*,0,*)``
| **Mode and number of proofs:**
|    ``findall_member(@term,+list,@callable,-list)`` - ``one``


------------

.. index:: findall_member/5
.. _metap/0::findall_member/5:

``findall_member/5``
^^^^^^^^^^^^^^^^^^^^

Finds all members of a list that satisfy a given test appending the given tail to the result.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``findall_member(Member,List,Test,Result,Tail)``
| **Meta-predicate template:**
|    ``findall_member(*,*,0,*,*)``
| **Mode and number of proofs:**
|    ``findall_member(@term,+list,@callable,-list,+list)`` - ``one``


------------

.. index:: partition/4
.. _metap/0::partition/4:

``partition/4``
^^^^^^^^^^^^^^^

Partition a list of elements in two lists using a predicate.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``partition(Closure,List,Included,Excluded)``
| **Meta-predicate template:**
|    ``partition(1,*,*,*)``
| **Mode and number of proofs:**
|    ``partition(+callable,+list,-list,-list)`` - ``one``


------------

.. index:: partition/6
.. _metap/0::partition/6:

``partition/6``
^^^^^^^^^^^^^^^

Partitions a list in lists with values less, equal, and greater than a given value using a comparison predicate with the same argument order as ``compare/3``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``partition(Closure,List,Value,Less,Equal,Greater)``
| **Meta-predicate template:**
|    ``partition(3,*,*,*,*,*)``
| **Mode and number of proofs:**
|    ``partition(+callable,+list,@term,-list,-list,-list)`` - ``one``


------------

.. index:: fold_left/4
.. _metap/0::fold_left/4:

``fold_left/4``
^^^^^^^^^^^^^^^

List folding (left associative). Closure is extended with three arguments: accumulator, list element, and updated accumulator.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``fold_left(Closure,Accumulator,List,Result)``
| **Meta-predicate template:**
|    ``fold_left(3,*,*,*)``
| **Mode and number of proofs:**
|    ``fold_left(+callable,?term,+list,?term)`` - ``zero_or_more``


------------

.. index:: fold_left_1/3
.. _metap/0::fold_left_1/3:

``fold_left_1/3``
^^^^^^^^^^^^^^^^^

List folding (left associative). Closure is extended with three arguments: accumulator, list element, and updated accumulator. The initial value of the accumulator is the list first element. Fails for empty lists.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``fold_left_1(Closure,List,Result)``
| **Meta-predicate template:**
|    ``fold_left_1(3,*,*)``
| **Mode and number of proofs:**
|    ``fold_left_1(+callable,+list,?term)`` - ``zero_or_more``


------------

.. index:: scan_left/4
.. _metap/0::scan_left/4:

``scan_left/4``
^^^^^^^^^^^^^^^

List scanning (left associative). Closure is extended with three arguments: accumulator, list element, and updated accumulator.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``scan_left(Closure,Accumulator,List,Results)``
| **Meta-predicate template:**
|    ``scan_left(3,*,*,*)``
| **Mode and number of proofs:**
|    ``scan_left(+callable,?term,+list,?list)`` - ``zero_or_more``


------------

.. index:: scan_left_1/3
.. _metap/0::scan_left_1/3:

``scan_left_1/3``
^^^^^^^^^^^^^^^^^

List scanning (left associative). Closure is extended with three arguments: accumulator, list element, and updated accumulator. The accumulator is initialized with the list first element. Fails for empty lists.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``scan_left_1(Closure,List,Results)``
| **Meta-predicate template:**
|    ``scan_left_1(3,*,*)``
| **Mode and number of proofs:**
|    ``scan_left_1(+callable,+list,?list)`` - ``zero_or_more``


------------

.. index:: fold_right/4
.. _metap/0::fold_right/4:

``fold_right/4``
^^^^^^^^^^^^^^^^

List folding (right associative). Closure is extended with three arguments: list element, accumulator, and updated accumulator.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``fold_right(Closure,Accumulator,List,Result)``
| **Meta-predicate template:**
|    ``fold_right(3,*,*,*)``
| **Mode and number of proofs:**
|    ``fold_right(+callable,?term,+list,?term)`` - ``zero_or_more``


------------

.. index:: fold_right_1/3
.. _metap/0::fold_right_1/3:

``fold_right_1/3``
^^^^^^^^^^^^^^^^^^

List folding (right associative). Closure is extended with three arguments: list element, accumulator, and updated accumulator. The initial value of the accumulator is the list first element. Fails for empty lists.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``fold_right_1(Closure,List,Result)``
| **Meta-predicate template:**
|    ``fold_right_1(3,*,*)``
| **Mode and number of proofs:**
|    ``fold_right_1(+callable,+list,?term)`` - ``zero_or_more``


------------

.. index:: scan_right/4
.. _metap/0::scan_right/4:

``scan_right/4``
^^^^^^^^^^^^^^^^

List scanning (right associative). Closure is extended with three arguments: list element, accumulator, and updated accumulator.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``scan_right(Closure,Accumulator,List,Results)``
| **Meta-predicate template:**
|    ``scan_right(3,*,*,*)``
| **Mode and number of proofs:**
|    ``scan_right(+callable,?term,+list,?list)`` - ``zero_or_more``


------------

.. index:: scan_right_1/3
.. _metap/0::scan_right_1/3:

``scan_right_1/3``
^^^^^^^^^^^^^^^^^^

List scanning (right associative). Closure is extended with three arguments: list element, accumulator, and updated accumulator. The accumulator is initialized with the list first element. Fails for empty lists.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``scan_right_1(Closure,List,Results)``
| **Meta-predicate template:**
|    ``scan_right_1(3,*,*)``
| **Mode and number of proofs:**
|    ``scan_right_1(+callable,+list,?list)`` - ``zero_or_more``


------------

.. index:: map/2
.. _metap/0::map/2:

``map/2``
^^^^^^^^^

True if the predicate succeeds for each list element.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``map(Closure,List)``
| **Meta-predicate template:**
|    ``map(1,*)``
| **Mode and number of proofs:**
|    ``map(+callable,?list)`` - ``zero_or_more``


------------

.. index:: map/3
.. _metap/0::map/3:

``map/3``
^^^^^^^^^

List mapping predicate taken arguments from two lists of elements.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``map(Closure,List1,List2)``
| **Meta-predicate template:**
|    ``map(2,*,*)``
| **Mode and number of proofs:**
|    ``map(+callable,?list,?list)`` - ``zero_or_more``


------------

.. index:: map/4
.. _metap/0::map/4:

``map/4``
^^^^^^^^^

List mapping predicate taken arguments from three lists of elements.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``map(Closure,List1,List2,List3)``
| **Meta-predicate template:**
|    ``map(3,*,*,*)``
| **Mode and number of proofs:**
|    ``map(+callable,?list,?list,?list)`` - ``zero_or_more``


------------

.. index:: map/5
.. _metap/0::map/5:

``map/5``
^^^^^^^^^

List mapping predicate taken arguments from four lists of elements.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``map(Closure,List1,List2,List3,List4)``
| **Meta-predicate template:**
|    ``map(4,*,*,*,*)``
| **Mode and number of proofs:**
|    ``map(+callable,?list,?list,?list,?list)`` - ``zero_or_more``


------------

.. index:: map/6
.. _metap/0::map/6:

``map/6``
^^^^^^^^^

List mapping predicate taken arguments from five lists of elements.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``map(Closure,List1,List2,List3,List4,List5)``
| **Meta-predicate template:**
|    ``map(5,*,*,*,*,*)``
| **Mode and number of proofs:**
|    ``map(+callable,?list,?list,?list,?list,?list)`` - ``zero_or_more``


------------

.. index:: map/7
.. _metap/0::map/7:

``map/7``
^^^^^^^^^

List mapping predicate taken arguments from six lists of elements.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``map(Closure,List1,List2,List3,List4,List5,List6)``
| **Meta-predicate template:**
|    ``map(6,*,*,*,*,*,*)``
| **Mode and number of proofs:**
|    ``map(+callable,?list,?list,?list,?list,?list,?list)`` - ``zero_or_more``


------------

.. index:: map/8
.. _metap/0::map/8:

``map/8``
^^^^^^^^^

List mapping predicate taken arguments from seven lists of elements.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``map(Closure,List1,List2,List3,List4,List5,List6,List7)``
| **Meta-predicate template:**
|    ``map(7,*,*,*,*,*,*,*)``
| **Mode and number of proofs:**
|    ``map(+callable,?list,?list,?list,?list,?list,?list,?list)`` - ``zero_or_more``


------------

.. index:: map_reduce/5
.. _metap/0::map_reduce/5:

``map_reduce/5``
^^^^^^^^^^^^^^^^

Map a list and apply a fold left (reduce) to the resulting list.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``map_reduce(Map,Reduce,Accumulator,List,Result)``
| **Meta-predicate template:**
|    ``map_reduce(2,3,*,*,*)``
| **Mode and number of proofs:**
|    ``map_reduce(+callable,+callable,+term,?list,?term)`` - ``zero_or_more``


------------

Protected predicates
--------------------

(none)

Private predicates
------------------

(none)

Operators
---------

(none)

.. seealso::

   :ref:`meta <meta/0>`