yesodweb/persistent

derivePersistField phantom type support

Aberta

#1.137 aberto em 23 de out. de 2020

 (8 comentários) (0 reação) (1 responsável)Haskell (302 forks)auto 404
Feature Requestgood first issue

Métricas do repositório

Stars
 (484 estrelas)
Métricas de merge de PR
 (Métricas PR pendentes)

Description

Phantom types are very useful for tagging things on type level, but at the moment this code will not compile

-- @Employment.hs
{-# LANGUAGE TemplateHaskell #-}
module Employment where

import Database.Persist.TH
import Prelude

data Employment a = Employed | Unemployed | Retired
    deriving (Show, Read, Eq)
derivePersistField "Employment a"

Guia do colaborador