function d3_scale_polylinear(domain, range, uninterpolate, interpolate) {

  var u = [],

      i = [],

      j = 0,

      n = domain.length;

  while (++j < n) {

    u.push(uninterpolate(domain[j - 1], domain[j]));

    i.push(interpolate(range[j - 1], range[j]));

  }

  return function(x) {

    var j = d3.bisect(domain, x, 1, domain.length - 1) - 1;

    return i[j](u[j](x));

  };

}