Implement saving+loading the game

Implement ToJSON and FromJSON for all of the various pieces of the game
state, and add a pair of functions saveGame/loadGame implementing a
prism to save the game as zlib-compressed JSON. To test this, there's
now Arbitrary, CoArbitrary, and Function instances for all the parts of
the game state - to get around circular imports with the concrete
entities this unfortunately is happening via orphan instances, plus an
hs-boot file to break a circular import that was just a little too hard
to remove by moving things around. Ugh.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/Xanthous/messages.yaml b/src/Xanthous/messages.yaml
index 1d8e066ed7a6..69664f8a7940 100644
--- a/src/Xanthous/messages.yaml
+++ b/src/Xanthous/messages.yaml
@@ -5,6 +5,10 @@ dead:
   - You perish...
   - You have perished...
 
+save:
+  location:
+    "Enter filename to save to: "
+
 entities:
   description: You see here {{entityDescriptions}}