Joseph Ferano
25f56c24a8
vendor/raylib/modes.flan: five macros over the five pairs the package binds -- with-drawing, with-mode-2d, with-mode-3d, with-texture-mode, with-scissor-mode. A second file with no declare-c in it, split out on vector.flan's reasoning: raylib.flan is the package's statement about C and nothing here names C, so nothing here can be made wrong by raylib changing. Each expands to (do (begin-... args) body... (end-...)) -- the calls the author used to type, in the order they typed them. No let, no gensym: nothing binds a name, so there is nothing for a caller's name to collide with. What it removes is the End* that is missing, wrong, or no longer beside its Begin*. What it cannot remove is a body leaving through the unwind path: a return or an invoke-restart skips the rest of the do and the End* with it. defer is the obvious fix and is refused inside a loop body, which is where a pair always lives -- checked, not assumed. So sand.flan's discipline stays: keep the restart boundary outside the pair. 35 call sites converted across examples/ and sand.flan. The one left is core-scissor-test.flan, whose Begin and End sit in two separate `when`s with the drawing between them -- a conditional pair is a shape a bracketing macro cannot express. test/programs/rl-with.flan covers with-scissor-mode, which no example can, with a frame function unreachable from main so it needs no libraylib; rl-with-reject.flan is the arity half.
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 `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/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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