.ghci for Windows 10 PowerShell when ANSI escapes don't work

.ghci

-- -*- coding: utf-8; comment-start: "-- "; comment-column: 40 -*-

-- NOTE: Can't follow :set commands with comments on same line.  Also, none of this works in PowerShell, hence the use
-- of System.Console.ANSI. :(

-- See https://stackoverflow.com/questions/4842424/list-of-ansi-color-escape-sequences
-- :set prompt "\ESC[7m%s\ESC[0m\nλ> "  -- Reverse video, two lines

-- Reverse video
-- :set prompt "\ESC[7mλ %s>\ESC[0m " 

-- :set prompt "\ESC[34;7mλ %s>\ESC[0m " -- Blue foreground, then video reversed.

-- Turquoise-ish foreground; then video reversed (formerly used on Mac).
-- :set prompt "\ESC[38;5;39;7mλ %s>\ESC[0m "

-- Plain lighter turquoise background (no reverse video):
-- :set prompt "\ESC[48;5;81mλ %s>\ESC[0m "

-- :set prompt "======== %s> "

-- Allow multi-line function definitions -- Not necessary if you use :{ and :} judiciously.
-- :set +m

-- Install System.Console.ANSI with 'cabal install ansi-terminal' (requires version 0.9+ of this package).
import System.Console.ANSI

data PromptType = NormalPrompt | ContinuationPrompt deriving (Eq, Show)

:{
-- We COULD specify the type here, but Haskell can figure it out and probably get it "righter" anyway.
-- let promptFunc :: (Integral a) => PromptType -> [String] -> a -> IO String
let promptFunc promptType modules _ = do
        if promptType == NormalPrompt then do
           setSGR [SetPaletteColor Background $ xterm6LevelRGB 2 4 5]   -- where color = xterm6LevelRGB ...?
           setSGR [SetColor Foreground Dull Black]
        else
           setSGR [SetPaletteColor Foreground $ xterm6LevelRGB 2 4 5] -- Not very visible on Mac (white background), but oh well.
        putStr $ (unwords $ filter ("System.Console.ANSI" /=) modules)
               ++ (if promptType == NormalPrompt then ">" else "|")
        setSGR [Reset]
        return " "
:}

-- myPromptFunc :: [String] -> Int -> IO String
-- myPromptFunc mods lineNum = do
--   putStr "======== PROMPT> "
--   return "PROMPT"

-- :set prompt-function \mods lineNum -> pure (show (mods, lineNum))
-- :set prompt-function \mods lineNum -> do; putStr "======== PROMPT> "; return ""
-- :set prompt-function \mods lineNum -> do; setSGR [SetColor Foreground Vivid Red]; setSGR [SetColor Background Vivid Blue]; putStr "======== PROMPT> "; setSGR [Reset]; return ""
     
-- :set prompt-function \mods lineNum -> do; setSGR [SetSwapForegroundBackground True]; putStr "PROMPT>"; setSGR [Reset]; return " "

-- :set prompt-function \modules lineNum -> do; setSGR [SetPaletteColor Background $ xterm6LevelRGB 1 4 5]; setSGR [SetColor Foreground Dull Black]; putStr $ (unwords $ filter ("System.Console.ANSI" /=) modules) ++ ">"; setSGR [Reset]; return " "

:set prompt-function (promptFunc NormalPrompt)
:set prompt-cont-function (promptFunc ContinuationPrompt)