2435.foo.less

#foo {
    // we even put our mixins into namespace to avoid any 
    // possible naming conflicts for our shared variables

    @primary: red;

    .some-button() {
        .button {
            color: @primary;
        }
    }
        
    .another-button() {
        .button {
            color: (#fff - @primary);
        }
    }
}