improve txtadv parser with hiding & splicing

beautiful-racket/br/demo/txtadv/expander.rkt

@@ -58,11 +58,6 @@
 (define #'(places-section (_place-id _place-desc [_place-item ...] [_actionname _actiondesc] ...) ...)
   #'(begin (define-place _place-id _place-desc [_place-item ...] ([_actionname _actiondesc] ...)) ...))
 
-(provide s-exp)
-(define-cases-inverting #'s-exp
-  [#'(_ _sx) #'_sx]
-  [#'(_ _sx ... ) #'(_sx ...)])
-
 
 ;; todo: consolidate the game-starters.
 ;; `start-game-at` works with s-exp language,

beautiful-racket/br/demo/txtadv/parser.rkt

@@ -20,10 +20,16 @@ places-section : !"===PLACES===" place-item+
 
 !place-item : DASHED-NAME STRING place-items id-desc+
 
-!place-items : !"[" ([!","] ID)* !"]"
+!place-items : !"[" [place next-place*] !"]"
+
+@place : ID
+
+@next-place: !"," place
 
 start-section : !"===START===" ID
 
 !id-desc : ID s-exp
 
-s-exp : ID | STRING | !"(" s-exp* !")"
+@s-exp : ID | STRING | nested-s-exp
+
+!nested-s-exp : !"(" s-exp* !")"

beautiful-racket/br/demo/txtadv/world-test.rkt

@@ -20,7 +20,6 @@
  "get key"
  "You now have the key.\n")
 
-
 (check-cmd?
  "n"
  "You're standing in a meadow. There is a house to the north.\n")