Can an optional LESS mixin variable refer to another variable

Question

Is it possible to refer to another variable in a parametric mixin?

.button(@textColor : @white, @iconColor : @textColor) {
    color: @textColor;
    i {
        color: @iconColor
    }
}

I want @iconColor to default to the value of @textColor.

The LESS compiler is complaining.

Answer 1

I think you need to do a nested mixin idea to get your functionality you want. LESS cannot tell that you have already set the @textColor and use that as the default setting for the second parameter. Instead, you need to do some type of guard expression. Here, I have made that guard expression a nested mixin that evaluates the second parameter within the main mixin and responds accordingly to get the @iconColor set:

.button(@textColor: @white, @setIconColor: null) {

    .setDefault() when (@setIconColor = null) {
       .doSetting(@textColor);
    }
    .setDefault() when (iscolor(@setIconColor)) {
       .doSetting(@setIconColor);
    }
    .setDefault();

    .doSetting(@iconColor) {    
        color: @textColor;
        i {
          color: @iconColor
        }
    }
}