astArrayExpression(arrNode, retArr) {
    const returnType = this.getType(arrNode);
    const arrLen = arrNode.elements.length;
    const elements = [];
    for (let i = 0; i < arrLen; ++i) {
      const element = [];
      this.astGeneric(arrNode.elements[i], element);
      elements.push(element.join(''));
    }
    switch (returnType) {
      case 'Matrix(2)':
      case 'Matrix(3)':
      case 'Matrix(4)':
        retArr.push(`[${elements.join(', ')}]`);
        break;
      default:
        retArr.push(`new Float32Array([${elements.join(', ')}])`);
    }
    return retArr;
  }
@desc Parses the abstract syntax tree for *Array* Expression
@param {Object} arrNode - the AST object to parse
@param {Array} retArr - return array string
@returns {Array} the append retArr