Derive HasField instances with Template Haskell.

A Template Haskell function to derive HasField instances to utilize OverloadedRecordDot more effectively.

Derive HasField instances

The OverloadedRecordDot syntax is surprisingly nice. I really enjoy writing code with this extension and I was originally hesistant.

Persistent has a really nice feature where it will automatically remove prefixes from models. Given a model like,

BankAccount
  accountNumber String

You would normally reference this field as bankAccountAccountNumber. However, with overloaded record dot you can write bankAccount.accountNumber which is much nicer.

At work, I really wanted this for every record. With this library, I can write,

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TemplateHaskell #-}

import DeriveHasField

data BankAccount =
  BankAccount
    { bankAccountAccountNumber :: String
    }

deriveHasField ''BankAccount

-- alternatively, for prefixes that don't match the data constructor name
deriveHasFieldWith (dropPrefix "bankAccount") ''BankAccount