Can we have this new addition in less or do we already have such things...

[mohammedzamakhan]

Addition to LessJS
Lets use $buttons as an example. Its primarily $modules
$buttons{
#btn
}
.btn{
}
$button-sml{
}
$button-med{
}
$button-lar{
}
}
How it all works!?
When ever it finds "$buttons{}" block in the code, it ignores the whole block, if it is not explicitly called.
if we import $buttons, we can use any syntax to import for example:
module $buttons;
It gets all the content of the block as well as the sub block contents. In our example code, #btn,.btn as well as sub-modules $button-sml, $button-med, $button-lar.
if we import sub module in our code, like:
module $buttons.$button-sml;
It gets al the content of the block i.e. #btn, .btn and also only $buttons.$button-sml block content

[seven-phases-max]

Please use backticks to format your code.
If I understand it right this feature already exists in LESS: "parametric namespace" (which essentially is just a parametric mixin containing another mixins), for example:

// define "module":

#buttons() {
    #btn {
        /* ... */
    }

    .btn {
        /* ... */
    }

    .pin() {
        color: red;
    }

    .button-sml() {
        // ...
    }

    .button-med() {
        // ...
    }

    .button-lar() {
        #tab {
            value: boo;
        }
    }
}

// ................
// usage:

#buttons(); // import "module", a.k.a "using namespace"

div {
    .pin;
}

span {
    // import "submodule", note that it does not include parent namespace "contents":
    #buttons.button-lar(); 
}

#tab {
    // import "submodule" including its parent "contents":
    #buttons;.button-lar(); 
}

Basically, a combination of parametric and non-parametric mixins, their nesting and expand/unlock order can be used to create virtually any "namespace/module" system one can imagine (see also this Q&A).
There're a few (relatively minor) issues with "parametric namespaces" though: #996, #1316, #1525.