Dynamic variables and mixins

Dynamic extends work fine. The following works as expected :

%#{$component} {
     // do something
}

Dynamic mixins and variables don’t seem to work, though. The following all give an error :

@mixin #{$component} {
     // do something
}

$var1 : parametername;
$$var1 : 5;

$var1 : parametername;
$#{$var1} : 5

Dynamic extends, mixins and variables increase the meta-programming capabilities of the language significantly. For that reason, I’m most definitely looking forward to the addition of dynamic mixins and/or variables to use them in the meta-framework I’m building.

Are these features planned for a future release? If not, is there a technical reason for that? Or is there maybe a technique you can recommend to achieve the same effect?

[jslegers]

I’m currently doing this :

// Definitions
@mixin setComponent($placeholder) {
  // Do stuff
  %#{$placeholder} {
      @content;
  }
}

@mixin getComponent($placeholder) {
  // Do stuff
  @extend %#{$placeholder};
}

// Example use
@include setComponent(table-cell) {
    padding:4px;
    margin:4px;
}

td {
    @include getComponent(table-cell);
}

th {
    @include getComponent(table-cell);
}

// Output

td, th {
  padding: 4px;
  margin: 4px;
}

Basicly, I’m looking for ways to achieve the following :

• support mixins as an alternative implementation for ‘setComponent’ and ‘getComponent’ dynamicly, based on the value of a global variable $extendComponents
• test whether or not a certain component has already been defined, to avoid duplication. This should work for mixins in Sass 3.3, but I don’t think an implementation exists for placeholders yet.

Both this and https://github.com/nex3/sass/issues/336 seem essential to allow these features and other features I have in mind for the meta-framework I’m building.

[fuwaraido]

I think modifying SASS syntax is not appropriate solution for these kind of things…now I’m using jinja template engine to generate SASS codes and it works so so fine. If SASS needs meta-programming abilities, implementing a good macro language on top of current syntax is the way to go!