The Evils of #region

25 March, 08:54 PM

#region is nice little commenting feature in C#. Functionally, it’s a comment, but one with a balanced structure, so you enclose a section of code in a #region / #endregion pair and your editor is supposed to allow you to collapse the entire region. It can be a useful way to organize code, particularly when you want to hide boilerplate stuff that’s necessary but noisy.

The evil part is that a region, when collapsed, can hide an arbitrarily large amount of code. I was just looking at a method where the programmer had neatly wrapped up each section of the method in #region with a comment describing what was going on in that section. It made a nice little method that nearly fit onto one screen… until you expanded the regions, all 200 lines of it. That’s the dark side of #region. You can easily hide a really stinky piece of code.

Really, it gets worse. You could seriously abuse regions, doing things like this

pre.public class Foo #region just because
{ public void Bar() { #endregion }
}

It’s contrived, but the point is that regions mostly offer another way to create obfuscated code. It’s one of those things that seems useful but when I reflect on what regions are intended for, stands out more as a red flag. Being able to collapse code is a useful feature, but I think the editor should use syntax – for example, collapsing scopes around curly braces, rather than around arbitrary points in a file.

— Gordon Weakliem

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Comment

  1. That’s exactly what XCode does (collapsing scopes around curly braces). Its nice, but I like being able to collapse whole sets of methods so that when I’m concentrating on one particular aspect of a class I can hide, and not have to scroll past, all the other stuff. Haven’t figured out how to do that in XCode yet.

    — Nick Harris · 26 March 2009, 07:36 · #

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