The trio the author decided on 2026-09-20 is now all built: def is CL's defparameter — its initialiser runs on every daemon re-run, unguarded, so an edited initialiser repaints the same storage on C-c C-c plus re-run — defonce (Clojure's name for CL's defvar, per the author) initialises once behind the .init~once. flag, and defconst stays the image. One parse arm reads both forms; the difference is Ast.reinit, carried to Tast.global's grerun. Emit.startup_plan gives a def no guard flag, and Check.check_global lifts every def initialiser — zero and literal included — into global/<n>, so the host's startup reaches it through the function cell and a re-evaluated def swaps it (Session's def_inits; Emit.redefinition declares the cell for a non-sibling target). The old defvar spelling is refused with the rename and both compiling spellings, and every program, test, doc and editor list is swept — except sand.flan, the author's live WIP, whose seven defvar lines are flagged in FIX.org and keep its three dependent tests red on this branch.
47 lines
1.8 KiB
Plaintext
47 lines
1.8 KiB
Plaintext
;;;; raylib [core] example - input keys
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;;;;
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;;;; examples/core/core_input_keys.c. Faithful, and the only thing worth noting
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;;;; is a Flan rule rather than a raylib one.
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;;;;
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;;;; The C moves the ball by writing `ballPosition.x += 2.0f` on a local
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;;;; struct. Flan has the same thing — a local IS an assignable place
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;;;; (spec-memory.md) — but the local has to be a `defonce` here rather than a
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;;;; `let` inside the loop, because a `let` binding is rebound every iteration
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;;;; and the position has to survive between frames. The C's variable is
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;;;; outside its while loop for the same reason; this is that, spelled with the
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;;;; storage the language has.
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;;;;
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;;;; `(set (.x ball) ...)` works on a struct field of a global: a field of an
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;;;; assignable place is itself one.
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(import rl "vendor:raylib")
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(defconst screen-width 800)
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(defconst screen-height 450)
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(defonce ball rl/Vector2)
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(defn main [] ()
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(rl/init-window screen-width screen-height
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"raylib [core] example - input keys")
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(defer (rl/close-window))
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(set ball (rl/Vector2 {.x (f32 (/ screen-width 2))
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.y (f32 (/ screen-height 2))}))
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(rl/set-target-fps 60)
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(until (rl/window-should-close?)
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;; Update. key-down? and not key-pressed?: this is meant to repeat for as
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;; long as the key is held, which is the whole difference between the two.
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(when (rl/key-down? :key-right) (set (.x ball) (+ (.x ball) 2.0)))
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(when (rl/key-down? :key-left) (set (.x ball) (- (.x ball) 2.0)))
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(when (rl/key-down? :key-up) (set (.y ball) (- (.y ball) 2.0)))
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(when (rl/key-down? :key-down) (set (.y ball) (+ (.y ball) 2.0)))
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;; Draw
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(rl/with-drawing
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(rl/clear-background rl/raywhite)
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(rl/draw-text "move the ball with arrow keys" 10 10 20 rl/darkgray)
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(rl/draw-circle-v ball 50.0 rl/maroon))))
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