Functional Lua stuff

function do_thing()
    map(fold(compose, sq, incr, incr, return_wrapper(print), incr, print, function() print("-") end), {1, 2, 3.2, 4, 5})
end

function return_wrapper(f)
    return function(a)
        f(a)
        return a
    end
end

function fold(f, a, b, ...)
    if b == nil then
        return a
    end
    
    local r = f(a, b)
    return fold(f, r, ...)
end

function compose(f, g)
    return function(a)
        return g(f(a))
    end
end

function map(f, t)
    local r = {}
    for i = 1, #t do
        r[i] = f(t[i])
    end
    
    return r
end



function incr(a)
    return a + 1    
end

function sq(a)
    return a * a
end

do_thing()