Joseph Ferano
9a820d86cd
The script is in tools/ rather than thrown away, because two lanes are
writing Flan in the old spelling right now and their files need the same
pass at merge.
It works on forms, not on text: a keyword becomes a dot only where it sits
in a field-label position inside a brace, so an enum member in value
position, a map key inside an EDN string and a type-position {K V} are all
left alone. :keys keeps its colon -- it names no field.
48 lines
1.8 KiB
Plaintext
48 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 `defvar` 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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(defvar 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? :right) (set (.x ball) (+ (.x ball) 2.0)))
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(when (rl/key-down? :left) (set (.x ball) (- (.x ball) 2.0)))
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(when (rl/key-down? :up) (set (.y ball) (- (.y ball) 2.0)))
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(when (rl/key-down? :down) (set (.y ball) (+ (.y ball) 2.0)))
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;; Draw
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(rl/begin-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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(rl/end-drawing)))
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