Generated by SassMeister.com. http://sassmeister.com/gist/64143f5242ee7a286d09

SassMeister-input-HTML.html

Arglist flexibility test   

URL: 
http://sassmeister.com/gist/64143f5242ee7a286d09 

SassMeister-input.scss

// ----
// Sass (v3.4.7)
// Compass (v1.0.1)
// ----

// 
// Arglist flexibility test   
// 
@mixin size($arglist...) {
  
  // Map arglist keywords 
  $map: keywords($arglist);
  
  // Map is empty
  @if inspect($map) == '()' {
  
    // Argument one is map 
    @if type-of(nth($arglist, 1)) == map {
      $map: nth($arglist, 1);
    } 
  
    // Argument one is list or value 
    // Note! this will break if mixin expects first 
    // regular argument to be a list
    @else {
      // Expected argument order
      $keys: width, height;   
      $list: if(type-of(nth($arglist, 1)) == list, nth($arglist, 1), $arglist);
      @for $i from 1 through length($list){
        $map:map-merge($map, (nth($keys, $i):nth($list, $i)));
      }
    }
  }  

  $width : map-get($map, width);  
  $height: map-get($map, height);  
  
  // If omitted height will 
  // default to width value
  $height: $width !default;  
  
  width : $width; 
  height: $height; 
 
 
}
.keyword-arguments{
  /* Only width */
  @include size($width: width-value);
  /* Only height */
  @include size($height: height-value);
  /* Normal order */
  @include size($width: width-value, $height: height-value);
  /* Reversed order */
  @include size($height: height-value, $width: width-value);
}

.map-arguments {
  /* Only width */
  $map:(width: width-value);
  @include size($map);
  /* Only height */
  $map:(width: width-value, height: height-value);
  @include size($map);
  /* Normal order */
  $map:(width: width-value, height: height-value);
  @include size($map);
  /* Reversed order */
  $map:(height: height-value, width: width-value);
  @include size($map);
}

.list-arguments {
  /* Only width */
  $list: width-value;
  @include size($list);
  /* Comma */
  $list: width-value, height-value;
  @include size($list);
  /* Space */
  $list: width-value height-value;
  @include size($list);
}

.arguments {
  /* Only width */
  @include size(width-value);
  /* Width and height */
  @include size(width-value, height-value);
}


// ==========================================================
// Functionalized version
@function map-arguments($arglist,$keys){
  $map: keywords($arglist);
  @if inspect($map)=='()' and length($arglist) > 0 {
    @if type-of(nth($arglist,1))==map{$map:nth($arglist,1);} 
    @else {$list:if(type-of(nth($arglist,1))==list,nth($arglist,1),$arglist);
      @for $i from 1 through length($list){$map:map-merge($map,(nth($keys,$i):nth($list,$i)));}
    }
  } @return $map;
}

@mixin my-mixin($arglist...) {
  $map   : map-arguments($arglist, (width, height));
  $width : map-get($map, width);  
  $height: map-get($map, height);  
  $height: $width !default;  
  width  : $width; 
  height : $height; 
}

SassMeister-output.css

.keyword-arguments {
  /* Only width */
  width: width-value;
  height: width-value;
  /* Only height */
  height: height-value;
  /* Normal order */
  width: width-value;
  height: height-value;
  /* Reversed order */
  width: width-value;
  height: height-value;
}

.map-arguments {
  /* Only width */
  width: width-value;
  height: width-value;
  /* Only height */
  width: width-value;
  height: height-value;
  /* Normal order */
  width: width-value;
  height: height-value;
  /* Reversed order */
  width: width-value;
  height: height-value;
}

.list-arguments {
  /* Only width */
  width: width-value;
  height: width-value;
  /* Comma */
  width: width-value;
  height: height-value;
  /* Space */
  width: width-value;
  height: height-value;
}

.arguments {
  /* Only width */
  width: width-value;
  height: width-value;
  /* Width and height */
  width: width-value;
  height: height-value;
}

SassMeister-rendered.html

Arglist flexibility test   

URL: 
http://sassmeister.com/gist/64143f5242ee7a286d09