function command( repl ) {
	return onCommand;

	/**
	* Returns a list of variable names in the current workspace.
	*
	* @private
	* @param {Options} [options] - function options
	* @param {RegExp} [options.include] - name inclusion filter
	* @param {RegExp} [options.exclude] - name exclusion filter
	* @param {ArrayLikeObject} [options.types] - type inclusion filter(s)
	* @param {boolean} [options.details] - boolean indicating whether to include additional variable details, such as variable type, contents, etc
	* @returns {(Array|void)} workspace variable names
	*/
	function onCommand( options ) {
		var opts;
		if ( arguments.length ) {
			opts = options;
		} else {
			opts = {};
		}
		return repl._context.varsWorkspace( repl._currentWorkspace, opts );
	}
}
Returns a callback to be invoked upon calling the `vars` command.

@private
@param {REPL} repl - REPL instance
@returns {Function} callback