SASS Mixin with optional and variable parameters

Is there a way to use both optional and variable elements in a sass mixin?

i try

@mixin name($className,  $centered: false, $dimension...)

but the first dimension value is assigned to $centered

switching parameters order don't compile

@mixin name($className, $dimension..., $centered: false )

the error is:

SASSInvalid CSS after "..., $dimension...": expected ")", was ", $centered: fa..."

since the mixin without the optional parameter is used in many place (over 70) i dont want yo change it all to add the new parameters, so i want to leave it optional?

Any way to change this mixin or i have to leave the original without $centered and create an ovverride with the new parameter?

for info this is the mixin body:

    @for $i from 1 through length($dimension){                              
        @if($centered) {
            .#{$className}Td#{$i}, .#{$className}Th#{$i}  { 
                width: nth($dimension, $i); 
                text-align:center;
            }
        }
        @else{
            .#{$className}Td#{$i}, .#{$className}Th#{$i} {width: nth($dimension, $i); }
        }
    }

EDIT with complete cowking example:

simply iam defining css for column width of my table in a faster way, so this

@include nome("columnsName", 40%, 30%, 30%);

is rendered in that way:

.columnsNameTd1, .columnsNameTh1{width: 40%;}

.columnsNameTd2, .columnsNameTh2{ width: 30%; }

.columnsNameTd3, .columnsNameTh3{ width: 30%;}

i want a way to text-align center all my columns, maybe can be interesting see if there is a way do to specify what column to center, making all other left by default

Solution

You can't do what you're asking because variable arguments (the ... syntax) absolutely must be last. You have 2 options, I recommend option #2.

Option 1 (examine the last element to see if it is a boolean):

@mixin name($className, $dimension...) {
    $last: nth($dimension, length($dimension));
    $centered: if(type-of($last) == bool, $last, false);
    $length: if(type-of($last) == bool, length($dimension) - 1, length($dimension));

    @for $i from 1 through $length {
        .#{$className}Td#{$i}, .#{$className}Th#{$i} {
            width: nth($dimension, $i);
            @if($centered) {
                text-align: center;
            }
        }
    }
}

Option 2 (use the @content directive):

@mixin name($className, $dimension...) {
    @for $i from 1 through length($dimension) {
        .#{$className}Td#{$i}, .#{$className}Th#{$i} {
            width: nth($dimension, $i);
            @content;
        }
    }
}

// usage
@include name(rar, 10%, 20%, 30%);

@include name(rar, 10%, 20%, 30%) {
    text-align: center;
}