flexible-defaults

Generate default function implementations for complex type classes.

https://github.com/mokus0/flexible-defaults

Version on this page:	0.0.1.2
LTS Haskell 24.18:	0.0.3
Stackage Nightly 2025-11-04:	0.0.3
Latest on Hackage:	0.0.3

See all snapshots flexible-defaults appears in

LicenseRef-PublicDomain licensed and maintained by James Cook

This version can be pinned in stack with:flexible-defaults-0.0.1.2@sha256:2ada668cd657927f5868f36db42b5a12ee00abba6520730a05de2f643809e05f,2419

Module documentation for 0.0.1.2

Language
- Language.Haskell
  - Language.Haskell.TH
    - Language.Haskell.TH.FlexibleDefaults

Depends on 5 packages(full list with versions):

base, containers, template-haskell, th-extras, transformers

Used by 1 package in nightly-2016-06-09(full list with versions):

random-source

Template Haskell code to implement default implementations for type-class functions based on which functions are already implemented. Currently extremely crude but still fairly effective.

When defining a type class with many functions, each of which can be implemented based on arbitrary subsets of the others, the standard default-implementation concept breaks down quite badly. This library provides a system by which more complex rules can be described for choosing default implementations based on which ones the user supplies. These implementations can additionally be given "suitability scores", so that when multiple possible choices could be made, the library can choose the "best" one.