// return a list of the fields in a tuple.
let fields = module{
    tpl = NULL,
} => {
    let reducer = macro(acc, field, value) => {
        result = acc + [field],
    };

    let result = reduce reducer.result [], (mod.tpl);
};

// return a list of the values in a tuple.
let values = module{
    tpl = NULL,
} => {
    let reducer = macro(acc, field, value) => {
        result = acc + [value],
    };

    let result = reduce reducer.result [], (mod.tpl);
};

let iter = module{
    tpl = NULL,
} => {
    let reducer = macro(acc, field, value) => {
        result = acc + [[field, value]],
    };
    
    let result = reduce reducer.result [], (mod.tpl);
};

let strip_nulls = module{
    tpl = NULL,
} => {
    let filterer = macro(name, value) => {
        result = value != NULL,
    };

    let result = filter filterer.result (mod.tpl);
};