Steshaw.hs

module Steshaw
  (length
  ,(|>)
  ,($>)
  ,(//)
  ,($$)
  ,(>.>)
  ,(>>>)
  ,unit
  ,d
  ,todo
  ,epsilon
  ,(%)
) where

import Prelude hiding (length)
import Data.List (genericLength)
import Control.Arrow ((>>>))

length = genericLength

(|>) = flip ($)

($>) = flip ($)

infixl 0 >$>
(>$>) = flip ($)

(//) = flip map

-- Needed a ($) that binds a little less tightly to make it easy to use with (>$>).
infixr 1 $$
($$) = ($)

-- NOTE: Probably just use Control.Arrow's (>>>) as an alternative.
-- Interestingly, Control.Arrow(>>>) is made infixr 1.
infixl 9 >.>
(>.>) = flip (.)

-- Alternative name for monadic return.
unit :: (Monad m) => a -> m a
unit = return

--
-- Attempt to simulate something similar to Ruby's number literal syntax. e.g. 260_000
--
-- e.g. d[260,000]
--
d :: (Num a) => [a] -> a
d = foldl (\ acc i -> acc * 1000 + i) 0

todo functionName = error $ "Implement " ++ functionName

epsilon = 1 $> iterate (/2) $> map (+1) $> takeWhile (/= 1) $> last $> (-) 1

(%) n = n / 100.0

{-
I don't know how established it is, but ($>) is a common name for flip($). Common, as in, I've seen three or so different people use it. IIRC, the F# name is (|>) but triangles are far too nice of a name and are often used for other things (e.g., cons and snoc). For what it's worth, this is the T combinator--- in case thrushes give you any ideas for names. Personally I'm more likely to use T as a prefix combinator rather than as infix, and for that the ($ _) section is good enough for me.

As for flip(.) we have (>>>) in Control.Arrow.
-}