38 lines
1,007 B
JavaScript
38 lines
1,007 B
JavaScript
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var Elm = Elm || {};
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Elm.Maybe = function() {
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function consMaybe(x) { return function(xs) {
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if (x[0] === "Just") return ["Cons", x[1], xs];
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return xs;
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};
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}
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function fromMaybe(b) { return function(m) {
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if (m[0] === "Just") return m[1];
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return b;
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};
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}
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function mapCons(f) { return function(y) { return function(xs) {
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var x = f(y);
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if (x[0] === "Just") return ["Cons", x[1], xs];
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return xs;
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};
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};
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}
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function maybe(b) { return function(f) { return function(m) {
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if (m[0] === "Just") return f(m[1]);
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return b;
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};
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};
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}
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return {Just : function(x) { return ["Just",x]; },
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Nothing : ["Nothing"],
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catMaybes : Elm.List.foldr(consMaybe)(["Nil"]),
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isJust : function(m) { return m[0] === "Just"; },
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isNothing : function(m) { return m[0] === "Nothing"; },
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fromMaybe : fromMaybe,
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consMaybe : consMaybe,
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mapMaybe : function(f) { return Elm.List.foldr(mapCons(f))(["Nil"]); },
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maybe : maybe
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};
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}();
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