class Funkcja

    def initialize
        @function = Proc.new
    end

    def value(x)
        return @function.call(x)
    end

    def poch(x) #http://www.obliczeniowo.com.pl/706
        f_x1 = @function.call(x)
        x += 0.0000001
        f_x2 = @function.call(x)
        return (f_x2 - f_x1) / 0.0000001
    end

    def pole(a, b) #http://www.obliczeniowo.com.pl/704
        dx = (b - a) / 100
        integr = 0
        (0..100).each do |i|
            i = (i * dx) + a
            fx1 = @function.call(i)
            i += dx
            fx2 = @function.call(i)
            integr += (0.5 * dx * (fx1 + fx2))
        end
        return integr
    end

    def zerowe(a,b,e)
        return "do zaimplementowania leniwy smieciu"
    end
end



syf = Funkcja.new{ |x| x*x }
puts syf.value(42)
puts syf.poch(1)
puts syf.pole(0,1)
puts syf.zerowe(0,0,0)