Pretty printing of `RUN` in shell form replaces multiple spaces in quoted string

[evolutics]

First of all, thanks for this helpful library.

The Dockerfile

FROM alpine
RUN echo 'a    b'

is pretty printed by prettyPrint as

FROM alpine
RUN echo 'a b'

I'd expect a quoted string to be left unchanged instead of reduced to 'a b'.

This happens not only with RUN instructions (in shell form), but also with health check commands.

A minimal code example is

module Main
  ( main
  ) where

import qualified Data.Either as Either
import qualified Data.Text as T
import qualified Data.Text.IO as T.IO
import qualified Data.Text.Lazy as Lazy
import qualified Language.Docker as Docker
import Prelude (IO, ($))

main :: IO ()
main = T.IO.putStr prettyPrinted
  where
    prettyPrinted = Lazy.toStrict $ Docker.prettyPrint parsed
    parsed = Either.fromRight [] $ Docker.parseText source
    source = T.pack "FROM alpine\nRUN echo 'a    b'\n"

I'm using version 9.1.1 of the library (via LTS Haskell 16.18).

[lorenzo]

@evolutics I'm sorry this flew under my radar for so long. I've been considering for a long time to just store the raw parsed text for RUN into the record so the pretty print does nothing with it at all.

I'll see if I can hack something together in the coming days