running gloss in ghci: closing the window with ESC produces "too many hs-exit()s"

[andrewufrank]

I want to use gloss with ghci (either stack repl or cabal repl. The gloss window opens nicely but when I close it, it also closes ghci. In an old but report I saw that the gloss window can be closed with ESC which returns control then to ghci. When I try this I get:

<interactive>: interrupted
<interactive>: warning: too many hs_exit()s

and ghci is closed.

I saw some discussion about running gloss with some flags (??), but could not find a comprehesible and likely up-to-date instruction. What is the correct procedure to run gloss graphics in ghci and how to interact with the windows (especially how to close them without closing ghci ?
Thank you!

I work with ghc 8.10.7 and gloss 1.13.2.1 (lts-18.28

[boblehest]

I see this issue is old, but I thought I might as well provide some pointers in case someone else comes by with the same problem;

Regarding flags I assume you mean compiling gloss to use the GLFW backend. If you're using cabal, you can add a file named cabal.project to the root folder of your project, with the following contents:

packages: .

constraints: gloss +GLFW -GLUT

This fixes the ghci problems for me, but on Windows (using freeGLUT) it causes gloss to crash when trying to render text.

I made a fork that works for me with freeGLUT on Windows (though it most likely doesn't work with old GLUT). To use it, I use the following cabal.project config:

packages: .

source-repository-package
    type: git
    location: https://github.com/boblehest/gloss
    tag: 3a75b107ff4df473c8ec5e023a4a8689b07393a4
    subdir: gloss