Scientific Calculator

silentmatt/functional-examples

By Matthew Crumley

Example implementations of some the built-in functional... functions.

Tagged: functional

Map = function(f, a) {
    var r = [];
    var i = 0;
    while (i < len a) -> (
        r[i] = f(a[i]);
        i += 1
    );
    r
};

Foldl = function(f, s, a) {
    var i = 0;
    (len @ < 3) and (a = s; s = a[0]; i = 1);
    while (i < len a) -> (
        s = f(s, a[i]);
        i += 1
    );
    s
};

Foldr = function(f, s, a) {
    var i;
    (len @ < 3) ? (a = s; i = len a - 1; s = a[i]) : (i = len a);
    while (i) -> (
        i -= 1;
        s = f(a[i], s)
    );
    s
};

Filter = function(p, a) {
    var i = 0;
    var r = [];
    var x;
    while (i < len a) -> (
        x = a[i];
        p(x) and (r[len r] = x);
        i += 1
    );
    r
};

Every = function(p, a) {
    apply(:and, map(p, a))
};

Some = function(p, a) {
    apply(:or, map(p, a))
};

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