//usage:
struct Vertex
{
    float position[3];
    float normal[3];
    float colour[4];
    float texCoord[2];
};

struct AttrData {
    const char* name;
    int         dim;
    int         byteoffset;
    int         stride_bytes;
    GLenum      gltype;
    OpenGLShaderProgram::Attribute  juce_attr;
};

#define ATTR( Vert, Attr, String ) \
    { \
        String, \
        std::extent<Vert::Attr>::value, \
        offsetof(V, pos), \
        sizeof(V), \
        glconst4type< std::remove_extent<V::pos>::type >::value \
    }

AttrData data[] = {
    ATTR_DATA( Vertex, position , "position"        ),
    ATTR_DATA( Vertex, normal   , "normal"          ),
    ATTR_DATA( Vertex, colour   , "sourceColour"    ),
    ATTR_DATA( Vertex, texCoord , "texureCoordIn"   )
}

struct Attr
{
    const OpenGLContext&        m_openGLContext;
    const OpenGLShaderProgram&  m_shader;
    const AttrData              m_data[];
    int N;

    Attr( OpenGLContext& context, OpenGLShaderProgram& shader, AttrData data[] )
    : m_openGLContext{context}, m_shader{shader}, m_data{data}
    {
        N = std::extent<data>::value;
    }

    void create() {
        for( int i=0; i<N; i++ )
            m_data[i].juce_attr = createAttribute( m_openGLContext, m_shader, m_data[i].name );
    }

    void setup()
    { ... }

    void disable()
    { ... }
}

Attr attrs(openGLContext, shader, data);

attrs.create();
attrs.setup();
attrs.disable();