(Hacky/crappy) Workaround for missing expressions in polymer 1.x

output.html

<div>  
    <h1>Missing expression eval hack.  Can we please get expressions in polymer2?</h1>
    <span>In stead of writing e.g. [­[1 + 2]­], write [­[_eval('1 + 2')]­]</span><br>

    <h4>Simple expressions</h4>
    Plain text: 1 + 2 = 3 <span>(in template: "3")</span><br>
    _eval hack: 1 + 2 = 3 <span>(in template: "[­[_eval('1 + 2']­]")</span><br>
    Expresison: 1 + 2 = [[1 + 2]] <span>(in template: "[­[1 + 2]­]")</span><br>

    <h4>Calling local functions (where this._getValue() returns 7)</h4>
    Plain text: _getValue() &amp; 0x3 = 3 <span>(in template: "3")</span><br>
    _eval hack: _getValue() &amp; 0x3 = 3 <span>(in template: "[­[_eval('this._getValue() &amp; 0x3')]­]")</span><br>
    Expression: _getValue() &amp; 0x3 = [[_getValue() &amp; 0x3]] <span>(in template: "[­[_getValue() &amp; 0x3]­]")</span><br>

    <h4>Using properties (where this.someval is set t orandom [0 - 9 every sec] - last: 7)</h4>
    _eval hack: someval * 2 = 14 <span>(in template: "[­[_eval('this.someval * 2', someval)]­]")</span><br>
    Expression: someval * 2 = [[someval * 2]] <span>(in template: "[­[someval * 2]­]")</span><br>
    <span>(Note: we are exploiting that _eval() ignores extra params (for notifications) ;))</span><br>

    <h4>Calling global functions</h4>
    Plain text: Math.floor(1.2) = 1 <span>(in template: "1")</span><br>
    _eval hack: Math.floor(1.2) = 1 <span>(in template: "[­[_eval('Math.floor(1.2)')]­]")</span><br>
    Expression: Math.floor(1.2) =  <span>(in template: "[­[Math.floor(1.2)]­]")</span><br>
    <span>(Note: the last one throws an exception and prints nothing: "compute method `Math.floor` not defined")</span>
</div>

sans-expression-hack.html

<link rel="import" href="../bower_components/polymer/polymer.html">
<dom-module id="sans-expression-hack">
  <template>
    <div>
        <style>
          span {
            color: #800;
            font-size: 0.9em;
          }
        </style>
        <h1>Missing expression eval hack.  Can we please get expressions in polymer2?</h1>
        <span>In stead of writing e.g. [&shy;[1 + 2]&shy;], write [&shy;[_eval('1 + 2')]&shy;]</span><br>

        <h4>Simple expressions</h4>
        Plain text: 1 + 2 = 3 <span>(in template: "3")</span><br>
        _eval hack: 1 + 2 = [[_eval('1 + 2')]] <span>(in template: "[&shy;[_eval('1 + 2']&shy;]")</span><br>
        Expresison: 1 + 2 = [[1 + 2]] <span>(in template: "[&shy;[1 + 2]&shy;]")</span><br>

        <h4>Calling local functions (where this._getValue() returns 7)</h4>
        Plain text: _getValue() & 0x3 = 3 <span>(in template: "3")</span><br>
        _eval hack: _getValue() & 0x3 = [[_eval('this._getValue() & 0x3')]] <span>(in template: "[&shy;[_eval('this._getValue() & 0x3')]&shy;]")</span><br>
        Expression: _getValue() & 0x3 = [[_getValue() & 0x3]] <span>(in template: "[&shy;[_getValue() & 0x3]&shy;]")</span><br>

        <h4>Using properties (where this.someval is set t orandom [0 - 9 every sec] - last: {{someval}})</h4>
        _eval hack: someval * 2 = [[_eval('this.someval * 2', someval)]] <span>(in template: "[&shy;[_eval('this.someval * 2', someval)]&shy;]")</span><br>
        Expression: someval * 2 = [[someval * 2]] <span>(in template: "[&shy;[someval * 2]&shy;]")</span><br>
        <span>(Note: we are exploiting that _eval() ignores extra params (for notifications) ;))</span><br>

        <h4>Calling global functions</h4>
        Plain text: Math.floor(1.2) = 1 <span>(in template: "1")</span><br>
        _eval hack: Math.floor(1.2) = [[_eval('Math.floor(1.2)')]] <span>(in template: "[&shy;[_eval('Math.floor(1.2)')]&shy;]")</span><br>
        Expression: Math.floor(1.2) = [[Math.floor(1.2)]] <span>(in template: "[&shy;[Math.floor(1.2)]&shy;]")</span><br>
        <span>(Note: the last one throws an exception and prints nothing: "compute method `Math.floor` not defined")</span>
    </div>
  </template>

  <script>
    Polymer({
      is: 'sans-expression-hack',

      properties: {
        someval: Number
      },

      attached: function() {
        this.someval = 0;
        setInterval(function() {
          this.set('someval', Math.floor(Math.random()*10));
        }.bind(this), 1000)
      },

      _eval: function(str) {
        return eval(str);
      },

      _getValue: function() {
        return 7;
      }
    });
  </script>
</dom-module>

Updated the gist with a property change example (random 'someval')