`list`¶

The list package provides higher-order utility functions for working with lists. All functions take a list as their first argument and are called via the list:: namespace.

import "list"

Package Functions¶

`iterator(_list)`¶

Creates a ListIterator instance wrapping the given list. See the iter documentation for the full ListIterator API.

Parameters

Type	Name	Description
`list`	`_list`	The list to iterate over.

Returns

Type	Description
`ListIterator`	An iterator over the list.

Example

import "list"

it = list::iterator([10, 20, 30])
while it.can_read() do
  println it.consume()
end
# prints: 10, 20, 30

`all(_list, _predicate)`¶

Returns true if every element in the list satisfies the predicate. Short-circuits on the first failure.

Parameters

Type	Name	Description
`list`	`_list`	The list to test.
`lambda`	`_predicate`	A single-argument lambda returning a boolean.

Returns

Type	Description
`boolean`	`true` if all elements satisfy the predicate, `false` otherwise.

Example

import "list"

println list::all([2, 4, 6], do (n) => n % 2 == 0)  # prints: true
println list::all([2, 3, 6], do (n) => n % 2 == 0)  # prints: false

`any(_list, _predicate)`¶

Returns true if at least one element in the list satisfies the predicate. Short-circuits on the first match.

Parameters

Type	Name	Description
`list`	`_list`	The list to test.
`lambda`	`_predicate`	A single-argument lambda returning a boolean.

Returns

Type	Description
`boolean`	`true` if at least one element satisfies the predicate.

Example

import "list"

println list::any([1, 3, 4], do (n) => n % 2 == 0)  # prints: true
println list::any([1, 3, 5], do (n) => n % 2 == 0)  # prints: false

`count(_list, _predicate)`¶

Returns the number of elements in the list that satisfy the predicate.

Parameters

Type	Name	Description
`list`	`_list`	The list to test.
`lambda`	`_predicate`	A single-argument lambda returning a boolean.

Returns

Type	Description
`integer`	The number of elements for which the predicate returns `true`.

Example

import "list"

println list::count([1, 2, 3, 4, 5], do (n) => n > 2)  # prints: 3

`find(_list, _predicate)`¶

Returns the index of the first element that satisfies the predicate, or -1 if no match is found.

Parameters

Type	Name	Description
`list`	`_list`	The list to search.
`lambda`	`_predicate`	A single-argument lambda returning a boolean.

Returns

Type	Description
`integer`	The zero-based index of the first matching element, or `-1`.

Example

import "list"

println list::find(["a", "bb", "ccc"], do (s) => s.size() > 1)  # prints: 1
println list::find(["a", "b"], do (s) => s.size() > 5)          # prints: -1

`first_where(_list, _predicate)`¶

Returns the first element that satisfies the predicate, or null if none is found.

Parameters

Type	Name	Description
`list`	`_list`	The list to search.
`lambda`	`_predicate`	A single-argument lambda returning a boolean.

Returns

Type	Description
`any`	The first matching element, or `null`.

Example

import "list"

result = list::first_where([1, 2, 3, 4], do (n) => n > 2)
println result  # prints: 3

`index_of(_list, _value)`¶

Returns the index of the first occurrence of _value in the list, or -1 if not found.

Parameters

Type	Name	Description
`list`	`_list`	The list to search.
`any`	`_value`	The value to look for.

Returns

Type	Description
`integer`	The zero-based index of the first occurrence, or `-1`.

Example

import "list"

println list::index_of(["x", "y", "z"], "y")  # prints: 1
println list::index_of(["x", "y", "z"], "w")  # prints: -1

`last_index_of(_list, _value)`¶

Returns the index of the last occurrence of _value in the list, or -1 if not found.

Parameters

Type	Name	Description
`list`	`_list`	The list to search.
`any`	`_value`	The value to look for.

Returns

Type	Description
`integer`	The zero-based index of the last occurrence, or `-1`.

Example

import "list"

println list::last_index_of([1, 2, 1, 3, 1], 1)  # prints: 4

`is_unique(_list)`¶

Returns true if every element in the list is distinct (no duplicates).

Parameters

Type	Name	Description
`list`	`_list`	The list to check.

Returns

Type	Description
`boolean`	`true` if all elements are unique.

Example

import "list"

println list::is_unique([1, 2, 3])     # prints: true
println list::is_unique([1, 2, 2, 3])  # prints: false

`last_where(_list, _predicate)`¶

Returns the last element that satisfies the predicate, or null if none is found. Searches the list in reverse order.

Parameters

Type	Name	Description
`list`	`_list`	The list to search.
`lambda`	`_predicate`	A single-argument lambda returning a boolean.

Returns

Type	Description
`any`	The last matching element, or `null`.

Example

import "list"

result = list::last_where([1, 2, 3, 4], do (n) => n % 2 == 0)
println result  # prints: 4

`none(_list, _predicate)`¶

Returns true if no element in the list satisfies the predicate.

Parameters

Type	Name	Description
`list`	`_list`	The list to test.
`lambda`	`_predicate`	A single-argument lambda returning a boolean.

Returns

Type	Description
`boolean`	`true` if no elements satisfy the predicate.

Example

import "list"

println list::none([1, 3, 5], do (n) => n % 2 == 0)  # prints: true
println list::none([1, 2, 5], do (n) => n % 2 == 0)  # prints: false

`one(_list, _predicate)`¶

Returns true if exactly one element in the list satisfies the predicate.

Parameters

Type	Name	Description
`list`	`_list`	The list to test.
`lambda`	`_predicate`	A single-argument lambda returning a boolean.

Returns

Type	Description
`boolean`	`true` if exactly one element matches.

Example

import "list"

println list::one([1, 2, 3], do (n) => n % 2 == 0)  # prints: true  (only 2)
println list::one([1, 2, 4], do (n) => n % 2 == 0)  # prints: false (two matches)

`reject(_list, _predicate)`¶

Returns a new list containing only the elements for which the predicate returns false. This is the inverse of the built-in .filter() method.

Parameters

Type	Name	Description
`list`	`_list`	The source list.
`lambda`	`_predicate`	A single-argument lambda returning a boolean.

Returns

Type	Description
`list`	A new list of elements that did not match the predicate.

Example

import "list"

result = list::reject([1, 2, 3, 4, 5], do (n) => n % 2 == 0)
println result  # prints: [1, 3, 5]

`sum_integer(_list)`¶

Computes the sum of all elements in the list that are of type integer. Non-integer values are silently ignored.

Parameters

Type	Name	Description
`list`	`_list`	A list of mixed values.

Returns

Type	Description
`integer`	The sum of all integer elements.

Example

import "list"

println list::sum_integer([1, 2.5, 3, "x", 4])  # prints: 8

`sum_float(_list)`¶

Computes the sum of all elements in the list that are of type float. Non-float values are silently ignored.

Parameters

Type	Name	Description
`list`	`_list`	A list of mixed values.

Returns

Type	Description
`float`	The sum of all float elements.

Example

import "list"

println list::sum_float([1, 1.5, 2.5, "x", 3])  # prints: 4.0

list¶

Package Functions¶

iterator(_list)¶

all(_list, _predicate)¶

any(_list, _predicate)¶

count(_list, _predicate)¶

find(_list, _predicate)¶

first_where(_list, _predicate)¶

index_of(_list, _value)¶

last_index_of(_list, _value)¶

is_unique(_list)¶

last_where(_list, _predicate)¶

none(_list, _predicate)¶

one(_list, _predicate)¶

reject(_list, _predicate)¶

sum_integer(_list)¶

sum_float(_list)¶

`list`¶

`iterator(_list)`¶

`all(_list, _predicate)`¶

`any(_list, _predicate)`¶

`count(_list, _predicate)`¶

`find(_list, _predicate)`¶

`first_where(_list, _predicate)`¶

`index_of(_list, _value)`¶

`last_index_of(_list, _value)`¶

`is_unique(_list)`¶

`last_where(_list, _predicate)`¶

`none(_list, _predicate)`¶

`one(_list, _predicate)`¶

`reject(_list, _predicate)`¶

`sum_integer(_list)`¶

`sum_float(_list)`¶