Relude

relude is a safe, performant, user-friendly and lightweight Haskell standard library.

Relude is the main module that reexports all functionality provided by the library that will replace the default Prelude in your project.

Usage

To start using relude in your project, you can set the library up for you by one of the following ways.

mixins

One of the most convenient ways to use relude is via the mixins feature. This feature is available since Cabal >= 2.2. In order to use the mixins feature one needs to specify supported cabal-version in your package description. And then the following lines should be added to the required stanza to replace default Prelude with relude.

cabal-version: 2.4
...
library
  ...
  mixins: base hiding (Prelude)
        , relude (Relude as Prelude)
        , relude

base-noprelude

Alternatively, you can replace base package in your dependencies with base-noprelude and add the following Prelude module to your package to use relude by default in every module instead of base Prelude:

module Prelude
    ( module Relude
    ) where

import Relude

NoImplicitPrelude

If you want to use relude per-module basis then just add next lines to your module to replace default Prelude:

{-# LANGUAGE NoImplicitPrelude #-}

import Relude

Structure

This documentation section contains the description of internal module structure to help navigate between modules, search for interesting functionalities and understand where you need to put your new changes (if you're a contributor).

Functions and types are distributed across multiple modules and grouped by meaning or category. Name of the module should give you hints regarding what this module contains. Some categories contain a significant amount of both reexported functions and functions of our own. To make it easier to understand these enormous chunks of functions, all reexported stuff is moved into the separate module with name Relude.SomeCategory.Reexport and our own functions and types are in Relude.SomeCategory.SomeName. For example, see modules Relude.Foldable.Fold and Relude.Foldable.Reexport.

Default Modules

module Relude.Applicative

Relude.Applicative contains reexports from Control.Applicative and some general-purpose applicative combinators.

module Relude.Base

Relude.Base contains different general types and type classes from base package (Char, Eq, Generic, etc.) not exported by other modules.

module Relude.Bool

Relude.Bool contains Bool data type with different predicates and combinators.

module Relude.Container

Relude.Container provides One typeclass for creating data structures from singleton element and reexports of types from packages containers and unordered-containers.

module Relude.Debug

Relude.Debug contains trace-like debugging functions with compile-time warnings (so you don't forget to remove them).

module Relude.DeepSeq

Relude.DeepSeq has reexports from Control.DeepSeq module and functions to evaluate expressions to weak-head normal form or normal form.

module Relude.Enum

Relude.Enum reexports Enum related typeclasses and functions. Also introduced a few useful helpers to work with Enums.

module Relude.Exception

Relude.Exception contains reexports from Control.Exception, introduces bug function as better error and Exc pattern synonym for convenient pattern-matching on exceptions.

module Relude.File

Relude.File implements functions to work with file content as Text or ByteString.

module Relude.Foldable

Relude.Foldable reexports functions for Foldable and Traversable and provide own better alternatives to some existing functions.

module Relude.Function

Relude.Function contains almost everything from the Data.Function module.

module Relude.Functor

Relude.Functor contains reexports from Data.Functor, Data.Bifunctor, other useful Functor combinators.

module Relude.Lifted

Relude.Lifted implements lifted to MonadIO functions to work with console, files, IORefs, MVars, etc.

module Relude.List

Relude.List provides big chunk of Data.List, NonEmpty type and functions for this type (head, tail, last, init).

module Relude.Monad

Relude.Monad contains functions and data types from Data.Maybe and Data.Either modules, monad transformers and other various combinators.

module Relude.Monoid

Relude.Monoid reexports various types and functions from Data.Monoid and Data.Semigroup.

module Relude.Nub

Relude.Nub implements better versions of nub function for list.

module Relude.Numeric

Relude.Numeric contains functions and types to work with numerical data.

module Relude.Print

Relude.Print contains printing to terminal functions for Text and ByteString.

module Relude.String

Relude.String contains reexports from text and bytestring packages with conversion functions between different textual types.

Extra Modules

The following modules are not exported by default, but you can easily bring them to every module in your package by modifying your Prelude file:

Relude.Extra	Reexports every Relude.Extra.* module
Relude.Extra.Bifunctor	Additional combinators for Bifunctor.
Relude.Extra.CallStack	Useful functions to extract information from CallStack.
Relude.Extra.Enum	Extra utilities for types that implement Bounded and Enum constraints.
Relude.Extra.Foldable	Extra folds for instances of the Foldable typeclass. Currently, just a short-circuitable left fold.
Relude.Extra.Foldable1	Foldable1 typeclass like Foldable but for non-empty structures.
Relude.Extra.Group	Grouping functions, polymorphic on return Map type.
Relude.Extra.Lens	Minimal implementation of lens package required for basic usage.
Relude.Extra.Map	Typeclass for Map-like data structures.
Relude.Extra.Newtype	Generic functions that automatically work for any newtype.
Relude.Extra.Tuple	Functions for working with tuples.
Relude.Extra.Type	Functions for inspecting and working with types.
Relude.Unsafe	Unsafe partial functions (produce error) for lists and Maybe.