Info on LESS Mixins - less

Question

Just a (hopefully) quick question about LESS Mixins:
Could these two mixins be combined somehow?, since they share a lot of the same information, just one adds an extra color.
.gradient-top(#color-1, #color-2){
background-color: #color-2;
background: -webkit-linear-gradient(top, #color-1, #color-2);
background: -moz-linear-gradient(top, #color-1, #color-2);
background: -ms-linear-gradient(top, #color-1, #color-2);
background: -o-linear-gradient(top, #color-1, #color-2);
background: linear-gradient(top, #color-1, #color-2);
}
.gradient-middle(#color-1, #color-2, #color-3){
background-color: #color-2;
background: -webkit-linear-gradient(top, #color-1, #color-2, #color-3);
background: -moz-linear-gradient(top, #color-1, #color-2, #color-3);
background: -ms-linear-gradient(top, #color-1, #color-2, #color-3);
background: -o-linear-gradient(top, #color-1, #color-2, #color-3);
background: linear-gradient(top, #color-1, #color-2, #color-3);
}

Answer 1

LESS supports accessing all the arguments passed to a mixin via the #arguments variable:
.gradient(#color-1, #color-2, ...) {
#gradient-stops: ~`"#{arguments}".slice(1, -1)`;
background-color: #color-2;
background: -webkit-linear-gradient(top, #gradient-stops);
background: -moz-linear-gradient(top, #gradient-stops);
background: -ms-linear-gradient(top, #gradient-stops);
background: -o-linear-gradient(top, #gradient-stops);
background: linear-gradient(top, #gradient-stops);
}
We need the selector interpolation (~) and the inline JavaScript evaluation (using backticks) to preserve the commas - otherwise, we would get background: linear-gradient(top, #color-1 #color-2 #color-n);, which is, of course, incorrect.
The other thing this mixin does is accept 2 or more arguments via the "rest" symbol (...) - this lets us call the mixing with three colors as well as two:
.gradient(#FFF, #CCC, #000) // A valid invocation of the mixin