/**
  * Compile the blueprint's column definitions.
  *
  * @param  \Illuminate\Database\Schema\Blueprint $blueprint
  * @return array
  */
 protected function getColumns(Blueprint $blueprint)
 {
     $columns = [];
     foreach ($blueprint->getAddedColumns() as $column) {
         // Each of the column types have their own compiler functions which are tasked
         // with turning the column definition into its SQL format for this platform
         // used by the connection. The column's modifiers are compiled and added.
         $sql = $this->wrap($column) . ' ' . $this->getType($column);
         $columns[] = $this->addModifiers($sql, $blueprint, $column);
     }
     return $columns;
 }