Is there a standard for "???", "!!!", "TODO" etc. tags in comments?

Question

I'm talking about special words/tokens used in the beginning of comments, to facilitate grepping or otherwise to attach some special meaning to the comment, like // TODO: Find out what to do about this error.

The meaning of some tags are obvious, like TODO and FIXME, but what about ??? and !!!? Are there others? I'm asking because I've seen the last two quite a lot recently and some editors, i.e. Xcode, provide a simple way to find all comments which such tags.

If there's no standard as such, I'm fine with a description of whatever company-local policy you might have. :)

Edit: Bonus points for referencing an actual document.

Answer 1

In Visual Studio, there's a "Task List", and the default tags (on VS2010) are "HACK", "TODO", "UNDONE" and "UnresolvedMergeConflict". So I would recommend using these if you are using Visual Studio.

Answer 2

We use Java with Eclipse and therefore the default Eclipse Tags TODO, FIXME and XXX. I use XXX when something is not really broken but very strange or should be done a different way.

Answer 3

I use !!! for code that must be fixed before it's committed. I use ??? for strange/should be done differently/just doesn't look right (always with an explanation).

Answer 4

This might help a bit:

http://en.wikipedia.org/wiki/Comment_%28computer_programming%29#Tags

I usually add "NOTE:" to my vim color schemes because many don't include it.

Answer 5

These questions in SO might be also helpful:

• http://stackoverflow.com/questions/77299/common-comment-tags
• http://stackoverflow.com/questions/335378/how-do-you-flag-code-so-that-you-can-come-back-later-and-work-on-it
• http://stackoverflow.com/questions/1452934/what-is-the-meaning-of-xxx
• http://stackoverflow.com/questions/2944360/tokens-in-visual-studio-hack-todo-any-other

Answer 6

We use the Doxygen tag \todo.

http://www.doxygen.nl/commands.html#cmdtodo

Answer 7

What ever you choose make sure you stick to it exactly. So if you go with // TODO make sure it's always that and never //TODO or // TO DO.

Why?

If it's just one string a simple search will find all places where it still exists in the code and you can more easily keep track of them.

Ideally you shouldn't have any - but we don't live (or work) in an ideal world.

Answer 8

There is not, though TODO is more common.

For a detailed research paper:

Storey, M.-A., J. Ryall, I. Bull, D. Myers, J. Singer, "TODO or To Bug: Exploring How Task Annotations Play a Role in the Work Practices of Software Developers," in Proceedings of the International Conference on Software Engineering, Leipzig, Germany, May 10-18, 2008.