Module-based programming

[Land]

I'm confused when it comes to modules.

I've read somewhere that modules are basically 'singleton
classes' and that anything that doesn't need its own state should
not needlessly be put inside a class.

But what if I want to create a simple OpenGL shader object. Do I
create a class like this:

class Shader
{
     // Method
     // Method
     // Method
     // Method

     // Field
     // Field
     // Field
}

Or do I have a structure that I operate on via module methods?
(C-style, basically)

struct Shader
{
     // Field
     // Field
     // Field
}

// Method
// Method
// Method
// Method

It's probably clear to you guys, but I'm stumped.

Thanks for any answers