Annotate haskell sample code

This library provides a simple but very limited way to quickly generate haskell source code annotated with its results. I find this useful when testing new packages and doing simple code demos.

A IHaskell notebook is a more robust alternative. However I like this approach when I'm doing something small/simple. The advantages being that it is lightweight and runs in a normal haskell executable so you can use template haskell etc.

Usage

Run a block of code in an exec block calling prn or pprn for anything you want to see output for. Select which printers you want to use. Currently they are printTerminal, printMarkdown and saveMarkdown

For example this code

{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}

module Main (main) where

import           Protolude

import qualified AnnotateExec as E

main :: IO ()
main = E.exec [E.printTerminal, E.saveMarkdown "./test.markdown"] $ do
  -- Normal comment
  let a = 1
  let b = 2
  E.prn $ a + b


  -- Space above is retained for console output but not markdown
  let b = [1,2,3]
  putText "not included in output"
  E.pprn $ b <> [4,5]

This will print the annotated results to the terminal with the results as comments below each prn and pprn.

The saveMarkdown printer will create markdown that looks like this

---

Main

{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}

module Main (main) where

import           Protolude

import qualified AnnotateExec as E

main :: IO ()
main = E.exec [E.printTerminal, E.saveMarkdown "./test.markdown"] $ do
  -- Normal comment
  let a = 1
  let b = 2
  E.prn $ a + b

>  3

  -- Space above is retained for console output but not markdown
  let b = [1,2,3]
  putText "not included in output"
  E.pprn $ b <> [4,5]

>  [ 1
>  , 2
>  , 3
>  , 4
>  , 5
>  ] 

---

GHCID

You can use ghcid to run and print your annotated code as you edit it

e.g. using ghcid and stack for this project's executable

stack exec -- ghcid -c "stack ghci annotateExec:lib --ghci-options='-fobject-code' --main-is annotateExec:exe:annotateExec-exe" --test=":main debug" -W