Sass @error use case

sass-error.scss

/**
 * Shape/Polygon/Triangle
 *
 * @author Maxime Thirouin maxime.thirouin@gmail.com @MoOx
 */
@mixin triangle($direction: top, $width: 1em, $height: 0, $color: #000)
{
    @if ($height == 0)
    {
        $height: $width;
    }
    
    width: 0;
    height: 0;
    
    @if ($direction == 'top')
    {
        border-left: $width solid transparent;
        border-right: $width solid transparent;
        border-bottom: $height solid $color;
    }
    @elseif ($direction == 'bottom')
    {
        border-left: $width solid transparent;
        border-right: $width solid transparent;
        border-top: $height solid $color;
    }
    @elseif ($direction == 'left')
    {
        border-top: $width solid transparent;
        border-right: $height solid $color;
        border-bottom: $width solid transparent;
    }
    @elseif ($direction == 'right')
    {
        border-top: $width solid transparent;
        border-left: $height solid $color;
        border-bottom: $width solid transparent;
    }
    @elseif ($direction == 'top-left')
    {
        border-top: $width solid $color;
        border-bottom: $width solid transparent;
        border-left: $width solid $color;
        border-right: $width solid transparent;
    }
    @elseif ($direction == 'top-right')
    {
        border-top: $width solid $color;
        border-bottom: $width solid transparent;
        border-left: $width solid transparent;
        border-right: $width solid $color;
    }
    @elseif ($direction == 'bottom-left')
    {
        border-top: $width solid transparent;
            border-bottom: $width solid $color;
        border-left: $width solid $color;
        border-right: $width solid transparent;   
    }
    @elseif ($direction == 'bottom-right')
    {
        border-top: $width solid transparent;
        border-left: $width solid transparent;
        border-bottom: $width solid $color;
        border-right: $width solid $color;
    }
    @else
    {
        // @error will be nice !!
        @warn 'The direction used does not exist';
    }
}

Warn is not enough.
Compass.app does not show warn (or I miss configure it)

As a work around:

module Sass::Script::Functions
   def error(message)
     raise Sass::SyntaxError, message.value
   end
end

@warn "#{error("The direction used does not exist")}";

I will try this. Thanks !