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)

## Public predicates

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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`

### `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)

See also

meta