let timeValue : float32 = glfwGetTime()
    let greenValue : float32 = sin(timeValue) / 2f + 0.5f
    let vertexColorLocation : int32 = glGetUniformLocation(shaderProgram, "ourColor")
    glUniform4f(vertexColorLocation, 0f, greenValue, 0f, 1f) # errors

--- error: ---

Error: unhandled exception: OpenGL error: invalid operation [GLerror]