flan/examples/core-window-should-close.flan
Joseph Ferano 49ec1651ae raylib enum keywords carry their enum's prefix
Key members are :key-r, :key-space, :key-left-shift; MouseButton members
are :mouse-left through :mouse-back — mouse- over button- because gamepads
have buttons too. Bare members collided across enums and with user code.

The bindings enum directive grew an optional third column declaring the
Flan-side member prefix, stripped before the C prefix is applied, so key-r
checks against KEY_R rather than KEY_KEY_R; a member that does not carry
the declared prefix is reported, not checked under a guessed name. The
enum-member error grew a did-you-mean: one edit away, or the bare name of
a prefixed member, so :r suggests :key-r.

sand.flan is the author's live WIP and is deliberately not touched; its
three keywords (lines 161-166) leave test_session and sand-headless red
until he moves them. Everything else that calls the two enums moved.
2026-09-20 21:49:11 +07:00

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;;;; raylib [core] example - window should close
;;;;
;;;; examples/core/core_window_should_close.c. Needed set-exit-key, and one
;;;; enum member to go with it: raylib.flan's `Key` now has `null 0`, read off
;;;; KEY_NULL in raylib.h. The binding is hand-written rather than taken from
;;;; the generated half because the Flan face differs — raylib declares
;;;; `void SetExitKey(int key)` and the generated line therefore takes an i32,
;;;; where this one takes a Key, so `(rl/set-exit-key :key-null)` is checked
;;;; against the enum and `:nul` is a compile error instead of a 0.
;;;;
;;;; The whole example is about what window-should-close? means. It is not a
;;;; flag raylib latches: it is "the close button was clicked, or the exit key
;;;; is down", recomputed each frame, and it goes back to false on its own.
;;;; That is what lets this program ask for confirmation and then carry on —
;;;; and it is also why the loop is driven by a `defvar` of its own rather
;;;; than by the predicate, which is the one structural difference from every
;;;; other example in this directory.
;;;;
;;;; `(set-exit-key :null)` takes ESC away from raylib so the program can read
;;;; it itself. The window's X button still works and is still what
;;;; window-should-close? reports.
(import rl "vendor:raylib")
(defconst screen-width 800)
(defconst screen-height 450)
(defvar exit-requested bool)
(defvar exiting bool)
(defn main [] ()
(rl/init-window screen-width screen-height
"raylib [core] example - window should close")
(defer (rl/close-window))
;; No key closes the window any more. ESC is an ordinary key from here on.
(rl/set-exit-key :key-null)
(rl/set-target-fps 60)
(until exiting
;; Update. Either way of asking to leave raises the question; only Y and N
;; answer it. window-should-close? is false again on the next frame, so
;; the request has to be remembered in a variable.
(when (or (rl/window-should-close?) (rl/key-pressed? :key-escape))
(set exit-requested true))
;; The C's `if (Y) ... else if (N) ...`, which is an `if` with a `when`
;; in its else and not a `cond`: a `cond` needs an `:else` arm and there
;; is nothing to do when neither key was pressed.
(when exit-requested
(if (rl/key-pressed? :key-y)
(set exiting true)
(when (rl/key-pressed? :key-n) (set exit-requested false))))
;; Draw
(rl/with-drawing
(rl/clear-background rl/raywhite)
(if exit-requested
(do
(rl/draw-rectangle 0 100 screen-width 200 rl/black)
(rl/draw-text "Are you sure you want to exit program? [Y/N]" 40 180 30
rl/white))
(rl/draw-text "Try to close the window to get confirmation message!"
120 200 20 rl/lightgray)))))