Thursday, November 12, 2009

Rant on XML Comments

The purpose of .NET XML comment is to help you generate outside documentation. When you tell Visual Studio to generate the XML file, you get tool tips when you hover over your method and you can use a tool like SandCastle to generate MSDN style help files based on your XML Comments. XML comments are really designed for Black Box documentation of Frameworks and API.

An XML comment is not the same as a development comment. When I am looking at a SandCastle generated help file, I care about how to use your class or method; I don’t care about why you chose to use a bubble sort over a quick sort.

I’ve seen comments like this:

/// DV

where DV is the initials of one of the developers. If you were actually use the XML comment feature, this comment would show up when you mouse over the class in Visual Studio or in the help file you created with SandCastle, same with this comment:

/// <summary>
/// This is the FooBar class!
/// I originally designed on a napkin after midnight after drinking 
/// a fifth of JD & eating 3 orders of hot wings.
/// I was inspired to write this class after Ellen, the goddess of 
/// the 327th Ave NE Pub down the street from my studio apartment,
/// who rejected me after I drank myself silly summoning up the 
/// courage  to ask her out.
/// </summary>

With the VS tooltip feature you lose all formatting, so if you have a comment like

/// <summary>
/// Foobar Class
/// Combines Bars with Foos and converts them from Metric to Imperial
/// 2005-04-13 – RN – Original implication 
/// 2005-05-03 – RF – Bug #12239 – g to # conversion issue
/// 2008-03-27 – VW – re-Implement Linq to Foo framework
/// </summary>

will appear on 1 or 2 lines without the linefeeds. The tags are ignored when VS creates tooltips.

I know that most of the projects I work on are not frameworks or API, but it still feel the need to avoid using XML comments for things other what I think they are designed for.

I am uptight about XML comments because I have used them, once. We created a help file for a client using SandCastle; the customer was impressed, though I bet they never used it.

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