Shortest template engine with JavaScript support and escaping

shortestTemplateEngine.js

//this is data // noprotect
var context = {
  keys:[0,1,2,3,null],
  key:"<b>test</b>"
};
 
//this is template
function _template(){
  for (var i=0; i < context.keys.length; i++) {
    div.b;
      if (context.keys[i] === 0) {
        span.raw('zero').span;
      } else {
        partial(_item, context.keys[i]);
      }
      span.raw(", index: " + i).span;
    div.e;
  }
  with (context){
    div.key.div;
  }
}
 
//this is also a template but it will be called as a sub template
function _item(){
  span['class="red"'].
     context!==null?context:'null value'
  .span;
}
 
//this is an "engine"
function render(_template_, context, logger, escape){
  var result, r = "",
      div = span = {},
      raw = function(t){return t;}
  escape == null && (escape = true);
  function partial(tmp, ctx) { return render(tmp, ctx, logger, false); }
  escape && (context = JSON.parse(JSON.stringify(context)
        .replace(/</g,'&lt;')
        .replace(/>/g,'&gt;')));
  result = _template_.toString()
        .replace(/function (\w+)\(\){/,'(function $1(){')
        .replace(/\}$/, '})()')
        .replace('partial(', 'r+=partial(')
        .replace(/(div|span)\.b/g, 'r+="<$1>";')
        .replace(/(div|span)\.e/g, 'r+="</$1>";')
        .replace(/(div|span)(?:\['([^.']+)'\])?\./g,"r+='<$1 $2>'+(")
        .replace(/\.(div|span)/g,')+"</$1>"')
        ;
  logger&&logger(result); eval(result);
  return r;
}
function compile(_template_){
  var result, r = "", ms,
      div = span = {},
      raw = function(t){return t;}
  result = _template_.toString()
        .replace(/function (\w+)\(\){/,'(function $1(){')
        .replace(/\}$/, '})()')
        .replace('partial(', 'partial(')
        .replace(/(div|span)\.b/g, 'r+="<$1>";')
        .replace(/(div|span)\.e/g, 'r+="</$1>";')
        .replace(/(div|span)(?:\['([^.']+)'\])?\./g,"r+='<$1 $2>'+(")
        .replace(/\.(div|span)/g,')+"</$1>"')
        ;
 var z =0;
  while (ms = result.match(/partial\([_\w\d\.]+/g)) {
    if (z > 100) break;
     for (var i=0; i<ms.length; i++) {
       var tn = ms[i].replace('partial(','');
       var com = compile(eval(tn), context);
       result = result.replace(tn, com.replace('})()','})'));
       z++;
     }
  }
  return result;
}
function run(result, context, escape){
  var result, r = "",
      div = span = {},
      raw = function(t){return t;}
  escape == null && (escape = true);
  escape && (context = JSON.parse(JSON.stringify(context)
        .replace(/</g,'&lt;')
        .replace(/>/g,'&gt;')));
  function partial(fn, ctx) {
      var oldCtx = context; 
      context = ctx; 
      fn();
      context = oldCtx;
  }
  eval(result)
  return r;
}

var ct = compile(_template);
console.time('templates render time');
//calling our render function
for(var i =0; i < 1000; i++) {// noprotect
  var res = run(ct, context);
  //var res = run(compile(_template), context);
  //var res = render(_template, context);
}
console.timeEnd('templates render time');
document.body.innerHTML = res;