55262170.1.less

// data:

@on-primary: #ffffff;
@icon-variants: active, inactive, disabled;
@icon-opacity-on-primary: 70, 50, 38;

// test:

div {
    r: .get-icon-color(inactive)[]; 
}

// functions:

.get-icon-color(@variant) {
    @index:  .index-of(@icon-variants, @variant)[];
    @opacity: extract(@icon-opacity-on-primary, @index);
    return:   fade(@on-primary, @opacity * 1%);    
}

.index-of(@list, @value-to-find) {
    each(@list, {
        & when (@value = @value-to-find) {
            return: @index; 
        }
    });
}