Argentum got a JSON module with both Parser and Writer.

Let's try Writer in action:

We'll use the same classes as in JSON Parser example:

class Point{
    x = 0f;
    y = 0f;
} 
class Polygon {
    name = "";
    points = Array(Point);
    isActive = false;
}

 This function converts an array of Polygons into a JSON string:

fn polygonsToJson(data Array(Polygon)) str {
    Writer.useTabs().arr {
        data.each `poly _.obj {
            _("name").str(poly.name);
            _("active").bool(poly.isActive);
            _("points").arr\poly.points.each `pt _.obj {
                _("x").num(double(pt.x));
                _("y").num(double(pt.y))
            }
        }
    }.toStr()
}

• As with parser, the JSON writer does not create any intermediate DOM-like data structures and as such has no memory and CPU overheads.
• It can produce both compact and pretty-printed JSONs, having configurable indentations.
• As with parser, the JSON-writing code has absolutely no syntax overhead - all it contains is field-name-to data mapping, data formatters and handlers of nested objects and arrays. No DSL could have more concise syntax.
• Combining parser and writer we can produce feature-rich JSON-handling applications running at a speed of native code and enjoying safety of managed one.