function extractColorOptions(expression) {
      var parts = expression.split('-');
      var hasTheme = angular.isDefined($mdTheming.THEMES[parts[0]]);
      var theme = hasTheme ? parts.splice(0, 1)[0] : $mdTheming.defaultTheme();

      return {
        theme: theme,
        palette: extractPalette(parts, theme),
        hue: extractHue(parts, theme),
        opacity: parts[2] || 1
      };
    }
For the evaluated expression, extract the color parts into a hash map
@param {string} expression color expression like 'red-800', 'red-A200-0.3',
  'myTheme-primary', or 'myTheme-primary-400'
@returns {{hue: *, theme: any, palette: *, opacity: (*|string|number)}}