Rename `=:` to `.=` and add `~~`.

{-# LANGUAGE OverloadedStrings #-}

-- | Small layer on top of @fast-logger@ which adds log-levels and

-- timestamp support and not much more.

-- timestamp support (using @date-cache@) and not much more.

module System.Logger

    ( Level    (..)

    , Output   (..)

instance IsString DateFormat where

    fromString = DateFormat . pack

-- | ISO 8601 date-time format.

iso8601UTC :: DateFormat

iso8601UTC = "%Y-%0m-%0dT%0H:%0M:%0SZ"

{-# LANGUAGE FlexibleInstances #-}

{-# LANGUAGE OverloadedStrings #-}

-- | 'Msg' and 'ToBytes' assist in constructing log messages.

-- For example:

--

-- @

-- > g <- new defSettings { bufSize = 1, output = StdOut }

-- > info g $ msg "some text" ~~ "key" .= "value" ~~ "okay" .= True

-- 2014-04-28T21:18:20Z, I, some text, key=value, okay=True

-- >

-- @

module System.Logger.Message

    ( ToBytes (..)

    , Msg

    , msg

    , field

    , (=:)

    , (.=)

    , (+++)

    , (~~)

    , val

    , render

    ) where

-- | Type representing log messages.

newtype Msg = Msg { builders :: [Builder] }

-- | Log some value.

-- | Turn some value into a 'Msg'.

msg :: ToBytes a => a -> Msg -> Msg

msg p (Msg m) = Msg (bytes p : m)

-- | Log some field, i.e. a key-value pair delimited by \"=\".

field, (=:) :: ToBytes a => ByteString -> a -> Msg -> Msg

-- | Render some field, i.e. a key-value pair delimited by \"=\".

field :: ToBytes a => ByteString -> a -> Msg -> Msg

field k v (Msg m) = Msg $ bytes k <> B.byteString "=" <> bytes v : m

infixr 5 =:

(=:) = field

-- | Alias of 'field'.

(.=) :: ToBytes a => ByteString -> a -> Msg -> Msg

(.=) = field

infixr 5 .=

infixr 5 +++

-- | Alias of '.' with lowered precedence to allow combination with '.='

-- without requiring parentheses.

(~~) :: (b -> c) -> (a -> b) -> a -> c

(~~) = (.)

infixr 4 ~~

-- | Concatenate two 'ToBytes' values.

(+++) :: (ToBytes a, ToBytes b) => a -> b -> Builder

a +++ b = bytes a <> bytes b

infixr 5 +++

-- | Type restriction. Useful to disambiguate string literals when

-- using @OverloadedStrings@ pragma.