Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.14)
// Compass (v1.0.0.rc.1)
// ----

// Global direction
// @type String
$global-direction: "ltr" !default;

// Global configuration
// @requires direction-configuration
// @type Map
$direction-configuration: direction-configuration();

// Returns the opposite value of `$value`
// @param {*} $value
// @return {*}
@function opposite-value($value) {
  @return if(index(left right, $value), if($value == left, right, left), $value);
}

@function define-value($value) {
  $global-direction: map-get($direction-configuration, "direction");
  
  @if $value == "start" {
    @return if($global-direction == "ltr", left, right);
  }
  @else if $value == "end" {
    @return if($global-direction == "rtl", right, left);
  }
  
  @return $value;
}

// Set up the global configuration
// @requires $global-direction
// @requires opposite-value
// @return Map
@function direction-configuration() {
  $global-side: if($global-direction == "rtl", right, left);
  $opposite-global-side: opposite-value($global-side);
  
  @return (
    direction: $global-direction,
    side: $global-side,
    opposite-side: $opposite-global-side
  );
}

// Define a directional value
// @requires $direction-configuration
// @param {*} $value
// @return {*}
@function directional-side($value) {
  $global-side: map-get($direction-configuration, "side");
  @return if($global-side == $value, $value, opposite-value($value));
}

// Output text align
// @param {String} $value
@mixin text-align($value) {
  @if index(left right, $value) {
    text-align: directional-side($value);
    @warn "Use native `text-align: start` or `text-align: end` native CSS declarations.";
  }
  
  @else {
    text-align: $value;
  }
}

// Output float
// @param {String} $value
@mixin float($value) {
  float: directional-side(define-value($value));
}

// Output clear
// @param {String} $value
@mixin clear($value) {
  @if index(left right, $value) {
    clear: directional-side($value);
  }
  
  @else if index(start end, $value) {
    clear: if($global-direction == "ltr" and $value == "start", left, right);
  }
  
  @else {
    clear: $value;  
  }
}

// Output left/right border
// @requires $direction-configuration
// @param {List} $value
@mixin border-start($value) {
  $global-side: map-get($direction-configuration, "side");
  border-#{$global-side}: $value;
}

// Output left/right border
// @requires $direction-configuration
// @param {List} $value
@mixin border-end($value) {
  $opposite-global-side: map-get($direction-configuration, "opposite-side");
  border-#{$opposite-global-side}: $value;
}

// Output left/right padding
// @requires $direction-configuration
// @param {Number} $value
@mixin padding-start($value) {
  $global-side: map-get($direction-configuration, "side");
  padding-#{$global-side}: $value;
}

// Output left/right padding
// @requires $direction-configuration
// @param {Number} $value
@mixin padding-end($value) {
  $opposite-global-side: map-get($direction-configuration, "opposite-side");
  padding-#{$opposite-global-side}: $value;
}

// Output left/right margin
// @requires $direction-configuration
// @param {Number} $value
@mixin margin-start($value) {
  $global-side: map-get($direction-configuration, "side");
  margin-#{$global-side}: $value;
}

// Output left/right margin
// @requires $direction-configuration
// @param {Number} $value
@mixin margin-end($value) {
  $opposite-global-side: map-get($direction-configuration, "opposite-side");
  margin-#{$opposite-global-side}: $value;
}

// Output direction
// @requires $global-direction
@mixin direction() {
  direction: unquote($global-direction);
}

// Direction content
// @requires $direction-configuration
// @requires $global-direction
// @access private
// @param {String} $direction
@mixin directional-content($direction) {
  $tmp: $global-direction;
  
  $global-direction: $direction !global;
  $direction-configuration: direction-configuration() !global;
  
  @content;
  
  $global-direction: $tmp !global;
  $direction-configuration: direction-configuration() !global;
}

// Local left-to-right
// @requires {mixin} directional-content
@mixin ltr {
  @include directional-content(ltr) { @content; }
}

// Local right-to-left
// @requires {mixin} directional-content
@mixin rtl {
  @include directional-content(rtl) { @content; }
}

.test-ltr {
  @include ltr {
    @include direction;
    @include clear(start);
    @include text-align(start);
    @include float(start);
    @include border-start(1px solid red);
    @include border-end(1px solid blue);
    @include padding-start(1em);
    @include padding-end(2em);
    @include margin-start(1em);
    @include margin-end(2em);
  }
}
 
.test-rtl { 
  @include rtl {
    @include direction;
    @include clear(start);
    @include text-align(start);
    @include float(start);
    @include border-start(1px solid red);
    @include border-end(1px solid blue);
    @include padding-start(1em);
    @include padding-end(2em);
    @include margin-start(1em);
    @include margin-end(2em);
  }
}

SassMeister-output.css

.test-ltr {
  direction: ltr;
  clear: left;
  text-align: start;
  float: left;
  border-left: 1px solid red;
  border-right: 1px solid blue;
  padding-left: 1em;
  padding-right: 2em;
  margin-left: 1em;
  margin-right: 2em;
}

.test-rtl {
  direction: rtl;
  clear: right;
  text-align: start;
  float: right;
  border-right: 1px solid red;
  border-left: 1px solid blue;
  padding-right: 1em;
  padding-left: 2em;
  margin-right: 1em;
  margin-left: 2em;
}