1 d3.scale.ordinal = function() {

     2   return d3_scale_ordinal([], {t: "range", x: []});

     3 };

     4 

     5 function d3_scale_ordinal(domain, ranger) {

     6   var index,

     7       range,

     8       rangeBand;

     9 

    10   function scale(x) {

    11     return range[((index[x] || (index[x] = domain.push(x))) - 1) % range.length];

    12   }

    13 

    14   function steps(start, step) {

    15     return d3.range(domain.length).map(function(i) { return start + step * i; });

    16   }

    17 

    18   scale.domain = function(x) {

    19     if (!arguments.length) return domain;

    20     domain = [];

    21     index = {};

    22     var i = -1, n = x.length, xi;

    23     while (++i < n) if (!index[xi = x[i]]) index[xi] = domain.push(xi);

    24     return scale[ranger.t](ranger.x, ranger.p);

    25   };

    26 

    27   scale.range = function(x) {

    28     if (!arguments.length) return range;

    29     range = x;

    30     rangeBand = 0;

    31     ranger = {t: "range", x: x};

    32     return scale;

    33   };

    34 

    35   scale.rangePoints = function(x, padding) {

    36     if (arguments.length < 2) padding = 0;

    37     var start = x[0],

    38         stop = x[1],

    39         step = (stop - start) / (domain.length - 1 + padding);

    40     range = steps(domain.length < 2 ? (start + stop) / 2 : start + step * padding / 2, step);

    41     rangeBand = 0;

    42     ranger = {t: "rangePoints", x: x, p: padding};

    43     return scale;

    44   };

    45 

    46   scale.rangeBands = function(x, padding) {

    47     if (arguments.length < 2) padding = 0;

    48     var start = x[0],

    49         stop = x[1],

    50         step = (stop - start) / (domain.length + padding);

    51     range = steps(start + step * padding, step);

    52     rangeBand = step * (1 - padding);

    53     ranger = {t: "rangeBands", x: x, p: padding};

    54     return scale;

    55   };

    56 

    57   scale.rangeRoundBands = function(x, padding) {

    58     if (arguments.length < 2) padding = 0;

    59     var start = x[0],

    60         stop = x[1],

    61         step = Math.floor((stop - start) / (domain.length + padding));

    62     range = steps(start + Math.round((stop - start - (domain.length - padding) * step) / 2), step);

    63     rangeBand = Math.round(step * (1 - padding));

    64     ranger = {t: "rangeRoundBands", x: x, p: padding};

    65     return scale;

    66   };

    67 

    68   scale.rangeBand = function() {

    69     return rangeBand;

    70   };

    71 

    72   scale.copy = function() {

    73     return d3_scale_ordinal(domain, ranger);

    74   };

    75 

    76   return scale.domain(domain);

    77 };