;;;; A program that stops with state worth looking at *outside* the frame.
;;;;
;;;; dev-locals.flan is about what one frame holds. This is about what the
;;;; whole stopped stack is reading, which in this language is most of the
;;;; program: a game keeps its state in top-level defvars, and sand.flan holds
;;;; its entire grid that way.
;;;;
;;;; The globals are declared in an order the answer must *not* come back in.
;;;; [label] is written first and is touched only by [main], the outer frame,
;;;; so ordering by the innermost frame that touches it has to put it last;
;;;; [grid] and [pressure] are both innermost-touched and must keep the order
;;;; they are declared in. [untouched] is read by no frame on the stack and
;;;; must not appear at all — that is the whole claim of scoping the section to
;;;; the stack rather than listing everything the program has.
(import agent "vendor:agent")

(defstruct Boom [why i32])

(defvar label    string)
(defvar grid     [4 i32])
(defvar pressure i64)
(defvar untouched i64 99)

;; The inner frame. It writes two globals and then errors with nothing
;; handling the condition, so the program stops here with [main] under it.
(defn inner [] i64
  (set pressure 12)
  (set (at grid 0) 7)
  (error (Boom {.why 3}))
  0)

(defn main [] i32
  (agent/start "/tmp/flan-dev-globals-fallback.sock")
  (set label "running")
  (set (at grid 1) 5)
  (print (inner)) (println "")
  (dotimes [i 4000]
    (agent/wait 5))
  0)