KeyLeft/Right/Up/Down interpreted as ESC on Mac OS X

[mcandre]

The docs show constructors for KeyLeft, KeyRight, KeyUp, and KeyDown, but when I press left, right, up, or down, they're all interpreted as Escape.

Example:

#!/usr/bin/env runhaskell

import UI.HSCurses.Curses

loopKey :: IO ()
loopKey = do
    k <- getCh
    putStrLn $ "Key: " ++ show k
    loopKey

main :: IO ()
main = do
    initCurses
    loopKey

(Press Up)

^[Key: KeyChar '\ESC'
                     [Key: KeyChar '['
                                      AKey: KeyChar 'A'

Specs:

hscurses 1.4.0.0 cabal 0.8.2 ghc 6.12.3 Mac OS X 10.6.6

[mcandre]

This issue raises several questions.

Why is there KeyLeft/Right/Up/Down and also cKEY_LEFT/RIGHT/UP/DOWN?

In GHCI, the c keys are distinct:

> cKEY_LEFT
260
> cKEY_RIGHT
261
> cKEY_LEFT == cKEY_RIGHT
False

So why does Haskell consider these patterns overlapping?

case k of
    cKEY_LEFT -> putStrLn $ "Pressed Left"
    cKEY_RIGHT -> putStrLn $ "Pressed Right"
    cKEY_UP -> putStrLn $ "Pressed Up"
    cKEY_DOWN -> putStrLn $ "Pressed Down"
    otherwise -> putStrLn $ "Pressed something else"

Why does this always evaluate to "Pressed something else"?

case k of
    cKEY_UP -> putStrLn $ "Pressed Up"
    otherwise -> putStrLn $ "Pressed something else"

And why does that always evaluate to "Pressed Up", no matter which arrow key is pressed?

[skogsbaer]

You need to add

keypad stdScr True

after initCurses and before loopKey