prelude.caddy

namespace {
    top = function(shape, amount) {
        let b = shape.bounds();
        let h = amount * b.height();
        shape.remove(b.translate(V2(0, h)))
    };

    left = function(shape, amount) {
        let b = shape.bounds().scale(V2(amount, 1));
        let w = amount * b.width();
        shape.remove(b.translate(V2(w, 0)))
    };

    right = function(shape, amount) {
        let b = shape.bounds().scale(V2(amount, 1));
        let w = amount * b.width();
        shape.remove(b.translate(V2(-w, 0)))
    };

    bottom = function(shape, amount) {
        let b = shape.bounds().scale(V2(1, amount));
        let h = amount * b.height();
        shape.remove(b.translate(V2(0, -h)))
    };

    list = namespace {
        head = function(lst) {
            lst[0]
        };
        tail = extern::tail;
    };

    vec = function(v) {
        if v.len() == 2
        then V2(v[0], v[1])
        else if v.len() == 3
             then V3(v[0], v[1], v[2])
             else V2(0, 0)
    };

    foldr = function(f, acc, lst) {
        let head = list::head(lst);
        let rest = this(f, acc, list::tail(lst));

        if lst == [] then acc else f(head, rest)
    };

    map = function(lst, f) {
        let comp = function(item, rest) {
            [f(item)] + rest
        };
        foldr(comp, [], lst)
    };

    map2 = function(lst, f) {
        lst.map(function(v) {
            f(v[0], v[1])
        })
    };

    enumerate = function(lst) {
        zip(range(0, len(lst), 1), lst)
    };

    diagonal = function(x) { [x, x] };

    triangle = namespace {
        iso = function(base, height) {
            polygon([V2(-base/2, 0), V2(base/2, 0), V2(0, -height)])
        };

        from_points = function(p1, p2, p3) {
            polygon([p1, p2, p3])
        };
    };

    rounded = namespace {
        triangle = namespace {
            iso = function(radius, base, height) {
                [
                    circle(radius).translate(V2(-base/2, 0)),
                    circle(radius).translate(V2(base/2, 0)),
                    circle(radius).translate(V2(0, -height))
                ].union().hull()
            };
        };

        rectangle = function(radius, width, height) {
            [
                circle(radius).translate(V2(-width/2, -height/2)),
                circle(radius).translate(V2(width/2, -height/2)),
                circle(radius).translate(V2(-width/2, height/2)),
                circle(radius).translate(V2(width/2, height/2))
            ].union().hull()
        };
    };

    color = namespace {
        from_rgb = function(r, g, b) { extern::color_rgb(r, g, b) };
        from_name = function(name) { extern::color_name(name) };
    };

    pattern = namespace {
        hatch = function(angle, thickness, fg, bg) { extern::make_hatch(angle, thickness, fg, bg) };
        crosshatch = function(angle, thickness, fg, bg) { extern::make_cross_hatch(angle, thickness, fg, bg) };
    };
}