ldoc

• Index

Contents

• Functions

Modules

• luafp.Maybe
• luafp.Result
• luafp.array
• luafp.collection
• luafp.func
• luafp.object
• luafp.predicates
• luafp.reactive
• luafp.util

Module luafp.collection

luafp collections module.

All functions that have more than 1 parameter are curried.

Functions

map (func, list)	takes a table in, runs the function on each item in the table, stores the results in a new table, and returns that table.
filter (func, list)	takes a table in, runs the predicate on each item in the table to filter out only the items you want.
reduce (func, accumulator, list)	takes a table in with an accumulator, runs the function on each item in the table, stores the results in the accumulator, and returns the final accumulator result.
every (func, list)	Takes a table and runs a predicate function on each item.
some (func, list)	Takes a table and runs a predicate function on each item.

Functions

map (func, list)

takes a table in, runs the function on each item in the table, stores the results in a new table, and returns that table.

Parameters:

• func function that takes the item from the table, and whatever you return goes into the new table.
• list Table of items you wish to map to someting else.

Returns:

1. list has your mapped items in it
2. string error message if parameter validation failed

Usage:

local collection = require 'luafp/collection'
ingredients = {'🐮', '🥔', '🐔', '🌽'}
function cook(item)
    if item == '🐮' then
        return '🍔'
    else if item == '🥔' then
        return '🍟'
    else if item == '🐔' then
        return '🍗'
    else if item == '🌽' then
        return '🍿'
    end
end
results = collection.map(ifCowTurnToChicken, ingredients)
-- results would be:
{'🍔', '🍟', '🍗', '🍿'}

filter (func, list)

takes a table in, runs the predicate on each item in the table to filter out only the items you want. For predicates that return true, the item will be included in a new list. If the predicate returns false, the item will not be included in the new list.

Parameters:

• func predicate function that takes the item from the table, expected to return true, if you want to keep the item, or false if you don't.
• list Table of items you wish to filter

Returns:

1. list has your filtered items in it, if any
2. string error message if parameter validation failed

Usage:

local collection = require 'luafp/collection'
food = {'🍔', '🍟', '🍗', '🍿'}
function isVegetarian(item)
    if item == '🍔' then
        return false
    else if item == '🍟' then
        return true
    else if item == '🍗' then
        return false
    else if item == '🍿' then
        return true
    end
end
results = collection.filter(isVegetarian, food)
-- results would be:
{'🍟', '🍿'}

reduce (func, accumulator, list)

takes a table in with an accumulator, runs the function on each item in the table, stores the results in the accumulator, and returns the final accumulator result.

Parameters:

• func reducer function; takes your item and current accumulator value in, and whatever you return is the new accumulator value.
• accumulator starting value for your reduce function
• list Table of items you wish to reduce.

Returns:

1. value Whatever the accumulator value is computed from your reducer.
2. string error message if parameter validation failed

Usage:

local collection = require 'luafp/collection'
food = {'🍔', '🍟', '🍗', '🍿'}
function eat(acc, item)
    return '💩'
end
results = collection.reduce(eat, food)
-- results would be:
{'💩'}

every (func, list)

Takes a table and runs a predicate function on each item. If all of them return true, then this function returns true, else false.

Parameters:

• func predicate function that takes each item of the list and is expected to return true or false.
• list Table of items you wish to verify.

Returns:

1. value true or false
2. string error message if parameter validation failed

Usage:

local collection = require 'luafp/collection'
animals = {'🐮', '🐔', '🐷'}
function isAnimal(item)
    if item == '🐷' or item == '🐔' or item == '🐷' then
        return true
    else
        return false
    end
end
allAnimals = collection.every(isAnimal, animals)
print(allAnimals) -- true

some (func, list)

Takes a table and runs a predicate function on each item. If at least one returns true, then this function returns true, else false.

Parameters:

• func predicate function that takes each item of the list and is expected to return true or false.
• list Table of items you wish to verify.

Returns:

1. value true or false
2. string error message if parameter validation failed

Usage:

local collection = require 'luafp/collection'
items = {'🐮', '🐔', '🐷', '🌽'}
function isPlant(item)
    if item == '🌽' then
        return true
    else
        return false
    end
end
hasAPlant = collection.some(isPlant, items)
print(hasAPlant) -- true