See TODO, Fixme, custom labels, and more in Xcode

//TODO: identify what will be done in the future;

//FIXME: Identify the content to be corrected or perfected later.

???: The place of doubt

!!!: Places to be aware of

The above four hints Xcode has been supported.

Add a custom identity and display it in warning at compile time;

Target-->build Phases-->editor-->add Run Script build phases

Paste the following code into the shell box

Keywords= "todo:|fixme:|???: |!!!: | XXX: "
Find "${srcroot}" \ (-name "*.h"-or-name "*.m" \)-print0 | xargs-0 egrep--with-filename--line-number--only-matching "($KEYWORDS). *\$" | Perl-p-E "s/($KEYWORDS)/warning: \$1/"

Reference:

Http://iosdevelopertips.com/xcode/xcode-fixme-and-todo.html

Https://coderwall.com/p/bfd0dq/xcode-view-todo-fixme-custom-tags-as-warning

See TODO, Fixme, custom labels, and more in Xcode