Experiment using Sass maps to organize Susy Next configuration. Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.0.rc.1)
// Compass (v0.13.alpha.10)
// ----

$grid: (
  small:                  90%  8 1/4,
  medium:                 80%  8 1/4,
  large:                  80% 12 1/4,
);

$content-grid: (
  left:                   100% (4 8) 1/4,
  right:                  100% (8 4) 1/4
);

@function _grid($map, $g, $attr: false) {
  $list: map-get($map, $g);
  @if $attr == container-width { @return nth($list, 1) }
  @if $attr == columns         { @return nth($list, 2) }
  @if $attr == gutters         { @return nth($list, 3) }
  @if $attr == total-columns {
    $columns: nth($list, 2);
    @if type-of($columns) != list { @return $columns }
    $sum: 0;
    @each $n in $columns {
      $sum: $sum + $n;
    }
    @return $sum;
  }
  @return $list;
}

@function grid($g, $attr: false) {
  @return _grid($grid, $g, $attr);
}

@function content-grid($g, $attr: false) {
  @return _grid($content-grid, $g, $attr);
}

output {
  a: length(map-get($grid, small));
  b: grid(small);
  c: grid(small, container-width);
  d: content-grid(left, gutters);
  e: grid(medium, columns);
  f: grid(medium, total-columns);
  g: content-grid(left, total-columns);
}

SassMeister-output.css

output {
  a: 3;
  b: 90% 8 1/4;
  c: 90%;
  d: 1/4;
  e: 8;
  f: 8;
  g: 12;
}

I just added the option to mix maps and keyword shorthand lists. It only required a few lines of code. :)

Wow, that's really cool!

I like the idea of putting grids into a map rather than using a variable for each grid because it provides something like a namespace. I've been doing this to organize other types of data, too, like colors and font-sizes. (When I say "I've been doing this," I mean in the few days since I started playing with Sass 3.3, haha.) Plus, with maps, you can do things like iteration that aren't possible with normal variables, even if they are semantically named.

I'm not not sure if this is something that should be part of Susy or if it's best left up to each person's individual preferences, but here's how it might work:

$_grids: ();

@mixin add-grid($g, $name) {
  $_grids: map-merge($_grids, ($name: $g));
}

@function grid($name) {
  @return map-get($_grids, $name);
}

$grid-1: 90%  8 1/4;
$grid-2: 100% (4 8) 1/4;

@include add-grid($grid-1, 1); // Add grid-1

a { output: grid(1) }
b { output: grid(2) } // Will output nothing since it hasn't been added yet

@include add-grid($grid-2, 2); // Add grid-2

c { output: grid(2) } // Now it is output

Essentially, this is just abstracting calls to map-get() and map-merge() to make the syntax more friendly.

I went ahead and created another Gist for the above: https://gist.github.com/acdlite/7308879

So if Susy used this pattern, my example grid() function above would correspond to susy-get().

Question: does susy-get() return the total number of columns in a grid? Not sure the best way to phrase this, but for instance, a grid with columns: (4 8) has a total of 12 columns. I think that would be a useful feature.