Debugging map returned by layout function. http://hugogiraudel.com/2013/10/21/sass-debug/

SassMeister-input.scss

// ----
// Sass (v3.3.4)
// Compass (v1.0.0.alpha.18)
// Susy (v2.1.1)
// ----

@import "compass";
@import "compass/reset";
@import "susy";


// Returns $list as a string
// -------------------------------------------------------------------------------
// @documentation http://sassylists.com/documentation/#debug
// -------------------------------------------------------------------------------
// @example debug(a b c d e)   => [ a, b, c, d, e ]
// @example debug(a b (c d e)) => [ a, b, [ c, d, e ] ]
// -------------------------------------------------------------------------------
// @param $list [List] : list
// @param $pre [Boolean] : enable/disable variables type and proper indentation
// @param $level [Number] : internal variable for recursivity
// -------------------------------------------------------------------------------
// @return [String]

@function debug($list, $pre: false, $level: 1) {
    $tab: "    ";
    $indent: "";
    $break: if($pre, "\A ", "");
  
    @if length($list) == 0 {
        @return "( )";
    }
  
    @if length($list) == 1 {
        @return if($pre,  "(" + type-of($list) + ") ", "") + $list;
    }

    @for $i from 1 to $level {
        $indent: $indent + $tab;
    }

    $result: "[" + $break;

    @for $i from 1 through length($list) {
        $item: nth($list, $i);
        $result: $result + if($pre, $indent + $tab, " ");

        @if length($item) > 1 {
            $result: $result 
                + if($pre, "(list: " + length($item) + ") ", "") 
                + debug($item, $pre, $level + 1);
        }

        @else {
            @if $pre {
                $result: $result + "(" + type-of($item) + ") ";
            }
      
            @if length($item) == 0 {
                $result: $result + "( )";
            }
      
            @else if type-of($item) == string {
                $result: $result + quote($item);
            }
      
            @else if $item == null {
                $result: $result + "null";
            }
      
            @else {
                $result: $result + $item;
            }
        }
    
        @if $i != length($list) {
            $result: $result + "," + $break;
        }
    }

    $result: $result + $break + if($pre, if($level > 1, $indent, ""), " ") + "]";

    @return quote($result);
}

// Mixin displaying clean debug
// -------------------------------------------------------------------------------
// @param $list [List] : list

@mixin debug($list) {
    body:before {
        content: debug($list, true)              !important;

        display: block                            !important;
        margin: 1em                               !important;
        padding: .5em                             !important; 

        background: #EFEFEF                       !important;
        border: 1px solid #DDD                    !important;
        border-radius: .2em                       !important;

        color: #333                               !important;
        font: .75em/1.5 "Courier New", monospace  !important;
        text-shadow: 0 1px white                  !important;
        white-space: pre-wrap                     !important;
    }
}

/**
 * Here is a cute list
 */
$list: (a #BADA55 42, (false (yummy cupcake)), 14px, "gloubiboulga", (), null);
$map: layout(24 1/4 fluid float inside);

/**
 * Awesome debug mixin is awesome
 */
// @include debug($list);
@include debug($map);

/**
 * Simple debug function
 */
body:after {
  display: block;
  content: debug($map);
}

SassMeister-output.css

html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed,
figure, figcaption, footer, header, hgroup,
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
  margin: 0;
  padding: 0;
  border: 0;
  font: inherit;
  font-size: 100%;
  vertical-align: baseline;
}

html {
  line-height: 1;
}

ol, ul {
  list-style: none;
}

table {
  border-collapse: collapse;
  border-spacing: 0;
}

caption, th, td {
  text-align: left;
  font-weight: normal;
  vertical-align: middle;
}

q, blockquote {
  quotes: none;
}
q:before, q:after, blockquote:before, blockquote:after {
  content: "";
  content: none;
}

a img {
  border: none;
}

article, aside, details, figcaption, figure, footer, header, hgroup, main, menu, nav, section, summary {
  display: block;
}

/**
 * Here is a cute list
 */
/**
 * Awesome debug mixin is awesome
 */
body:before {
  content: "[\A     (list: 2) [\A         (string) math,\A         (string) fluid\A     ],\A     (list: 2) [\A         (string) output,\A         (string) float\A     ],\A     (list: 2) [\A         (string) gutter-position,\A         (string) inside\A     ],\A     (list: 2) [\A         (string) columns,\A         (number) 24\A     ],\A     (list: 2) [\A         (string) gutters,\A         (number) 0.25\A     ]\A ]" !important;
  display: block                            !important;
  margin: 1em                               !important;
  padding: .5em                             !important;
  background: #EFEFEF                       !important;
  border: 1px solid #DDD                    !important;
  border-radius: .2em                       !important;
  color: #333                               !important;
  font: .75em/1.5 "Courier New", monospace  !important;
  text-shadow: 0 1px white                  !important;
  white-space: pre-wrap                     !important;
}

/**
 * Simple debug function
 */
body:after {
  display: block;
  content: "[ [ math, fluid ], [ output, float ], [ gutter-position, inside ], [ columns, 24 ], [ gutters, 0.25 ] ]";
}