_directional.scss

// directional-scss
$dir: ltr !default;

// Default $dir if not valid
@if $dir != ltr and $dir != rtl {
    $dir: ltr;
}

@function if-ltr($if, $else: null) {
    @if $dir != rtl {
        @return $if;
    }
    @else {
        @return $else;
    }
}

@function if-rtl($if, $else: null) {
    @return if-ltr($else, $if);
}

$left: if-ltr(left, right);
$right: if-ltr(right, left);

@function side-values($values) {
    @if $dir == rtl and length($values) >= 4 {
        // Reorder right and left positions in list
        @return nth($values, 1) nth($values, 4) nth($values, 3) nth($values, 2);
    }
    @else {
        @return $values;
    }
}

@function corner-values($values) {
    @if $dir == rtl and length($values) > 1 {
        // Reorder right and left positions in list
        @if length($values) == 2 {
            @return nth($values, 2) nth($values, 1);
        }
        @else if length($values) == 3 {
            @return nth($values, 2) nth($values, 1) nth($values, 2) nth($values, 3);
        }
        @else {
            @return nth($values, 2) nth($values, 1) nth($values, 4) nth($values, 3);
        }
    }
    @else {
        @return $values;
    }
}

@function dir-values($values) {
    @if $dir == rtl and length($values) == 4 {
        // Reorder right and left positions in list
        @return nth($values, 1) nth($values, 4) nth($values, 3) nth($values, 2);
    }
    @else {
        @return $values;
    }
}

@mixin if-ltr {
    @if $dir != rtl {
        @content;
    }
}

@mixin if-rtl {
    @if $dir == rtl {
        @content;
    }
}