72 lines
2 KiB
JavaScript
72 lines
2 KiB
JavaScript
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Elm.Native.Keyboard = function(elm) {
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'use strict';
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elm.Native = elm.Native || {};
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if (elm.Native.Keyboard) return elm.Native.Keyboard;
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var Signal = Elm.Signal(elm);
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var NList = Elm.Native.List(elm);
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var keysDown = Signal.constant(NList.Nil);
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var charPressed = Signal.constant('\0');
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function down(e) {
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if (NList.member(e.keyCode)(keysDown.value)) return;
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var list = NList.Cons(e.keyCode, keysDown.value);
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var hasListener = elm.notify(keysDown.id, list);
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if (!hasListener) elm.node.removeEventListener('keydown', down);
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}
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function up(e) {
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function notEq(kc) { return kc !== e.keyCode; }
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var codes = NList.filter(notEq)(keysDown.value);
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var hasListener = elm.notify(keysDown.id, codes);
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if (!hasListener) elm.node.removeEventListener('keyup', up);
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}
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function blur(e) {
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var hasListener = elm.notify(keysDown.id, NList.Nil);
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if (!hasListener) elm.node.removeEventListener('blur', blur);
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}
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function press(e) {
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var hasListener = elm.notify(charPressed.id, e.charCode || e.keyCode);
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if (!hasListener) elm.node.removeEventListener('keypress', press);
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}
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elm.node.addEventListener('keydown' , down );
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elm.node.addEventListener('keyup' , up );
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elm.node.addEventListener('blur' , blur );
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elm.node.addEventListener('keypress', press);
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function keySignal(f) {
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var signal = A2( Signal.lift, f, keysDown );
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keysDown.defaultNumberOfKids += 1;
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signal.defaultNumberOfKids = 0;
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return signal;
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}
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function dir(up, down, left, right) {
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function f(ks) {
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var x = 0, y = 0;
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while (ks.ctor == "Cons") {
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switch (ks._0) {
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case left : --x; break;
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case right: ++x; break;
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case up : ++y; break;
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case down : --y; break;
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}
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ks = ks._1;
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}
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return { _:{}, x:x, y:y };
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}
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return keySignal(f);
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}
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function is(key) { return keySignal(NList.member(key)); }
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return elm.Native.Keyboard = {
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isDown:is,
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directions:F4(dir),
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keysDown:keysDown,
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lastPressed:charPressed
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};
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};
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