Template strings

Simple string substitution library that supports "$"-based substitution. Meant to be used when Text.Printf or string concatenation would lead to code that is hard to read but when a full blown templating system is overkill.

Usage example:

{-# LANGUAGE OverloadedStrings #-}
module Main where

import qualified Data.ByteString.Lazy as S
import qualified Data.Text as T
import qualified Data.Text.Lazy.Encoding as E

import Data.Text.Template

-- | Create 'Context' from association list.
context :: [(T.Text, T.Text)] -> Context
context assocs x = maybe err id . lookup x $ assocs
  where err = error $ "Could not find key: " ++ T.unpack x

main :: IO ()
main = S.putStr $ E.encodeUtf8 $ substitute helloTemplate helloContext
  where
    helloTemplate = "Hello, $name!\n"
    helloContext  = context [("name", "Joe")]