doc[haddock]: examples and comments

src/Language/Brainfuck.hs

@@ -1,7 +1,10 @@
 {-# LANGUAGE ImportQualifiedPost #-}
 {-# LANGUAGE DerivingStrategies #-}
 {-# LANGUAGE LambdaCase #-}
-module Language.Brainfuck (parse, ParseFailure, render) where
+
+-- | This module allows you to parse and manipulate brainfuck programs. Currently there are no re-exports here, you may need to look into submodules to find the operations you need.
+
+module Language.Brainfuck (parse, ParseFailure(..), render) where
 
 import Control.Monad.ST (runST, ST)
 
@@ -16,14 +19,32 @@ import Language.Brainfuck.Instruction ( Instruction(..) )
 import qualified Data.List as List
 import Numeric.Natural (Natural)
 
+-- | Brainfuck has only two types of syntax errors: either too many open brackets or too many closed brackets, this is the failure type.
+
 data ParseFailure
-  = UnexpectedClosingBracket Natural -- closing bracket position
-  | UnmatchedOpenBracket Natural -- opening bracket position
+  = UnexpectedClosingBracket Natural 
+  -- ^ closing bracket position
+  | UnmatchedOpenBracket Natural 
+  -- ^ opening bracket position
   deriving stock (Show, Eq)
 
 -- | Convert a Text to a list of instructions, discard all comments.
 --
 -- Recognized instructions are in the string "+-<>,.[]", they are represented as a Enum Type.
+--
+-- ==== __Examples__
+--
+-- >>> parse $ Text.pack "<<>>,,..<,.>"
+-- Right [MoveLeft,MoveLeft,MoveRight,MoveRight,ReadByte,ReadByte,PutByte,PutByte,MoveLeft,ReadByte,PutByte,MoveRight]
+--
+-- >>> parse $ Text.pack "[-]++<<<[>-[+-+-+]]>+"
+-- Right [Loop [Decrement],Increment,Increment,MoveLeft,MoveLeft,MoveLeft,Loop [MoveRight,Decrement,Loop [Increment,Decrement,Increment,Decrement,Increment]],MoveRight,Increment]
+--
+-- >>> parse $ Text.pack "["
+-- Left (UnmatchedOpenBracket 0)
+--
+-- >>> parse $ Text.pack "[]]"
+-- Left (UnexpectedClosingBracket 2)
 
 parse :: Text -> Either ParseFailure (Vector Instruction)
 parse text = runST $ do
@@ -75,18 +96,17 @@ parse text = runST $ do
                     _ -> pure innerResult
                 _   -> parseBlock cs instructions index
 
-
--- >>> parse $ Text.pack "<<>>,,..<,.>"
--- Right [MoveLeft,MoveLeft,MoveRight,MoveRight,ReadByte,ReadByte,PutByte,PutByte,MoveLeft,ReadByte,PutByte,MoveRight]
-
--- >>> parse $ Text.pack "[-]++<<<[>-[+-+-+]]>+"
--- Right [Loop [Decrement],Increment,Increment,MoveLeft,MoveLeft,MoveLeft,Loop [MoveRight,Decrement,Loop [Increment,Decrement,Increment,Decrement,Increment]],MoveRight,Increment]
-
--- >>> parse $ Text.pack "["
--- Left (UnmatchedOpenBracket 0)
-
--- >>> parse $ Text.pack "[]]"
--- Left (UnexpectedClosingBracket 2)
+-- | Render a series of instructions into a program text.
+--
+-- This is not exactly an inverse of 'parse' because parse will discard all comments and may fail with the 'Left' constructor.
+--
+-- ==== __Examples__
+--
+-- >>> render $ Vector.fromList [Increment,Increment, Loop $ Vector.fromList [Decrement, MoveRight, Increment, MoveLeft]]
+-- "++[->+<]"
+--
+-- >>> fmap render . parse $ Text.pack "++ [ ->+< ] comment"
+-- Right "++[->+<]"
 
 render :: Vector Instruction -> Text
 render = Text.concat . List.map renderSingle . Vector.toList

src/Language/Brainfuck/Instruction.hs

@@ -1,5 +1,8 @@
 {-# LANGUAGE DerivingStrategies #-}
 {-# LANGUAGE InstanceSigs #-}
+
+-- | This is the native brainfuck instruction representation. They can be easily mapped to and from a program text.
+
 module Language.Brainfuck.Instruction (Instruction(..)) where
 
 import Data.Vector ( Vector )
@@ -9,6 +12,8 @@ import Test.QuickCheck.Instances.Vector ()
 
 import qualified Test.QuickCheck.Gen as Gen
 
+-- | The native brainfuck instruction. Does not allow comments, they must be discarded whilst parsing.
+
 data Instruction
   = Increment
   | Decrement