Listing All TODOs

People’s coding styles tend to evolve and change over time. One particular habit I seem to have picked up is to sprinkle the code liberally with numerous TODO markers. I wish I could say it’s clear a sign of my ever-present dissatisfaction with imperfect solutions, but I suspect I simply adopted it while working at the current company :)

In any case, TODOs (and FIXMEs &c.) are not actually something to scoff at, not too much at least. They are certainly better than the alternative, which is to commit shady code without explanation, rationale, or ideas for improvement. With TODOs, you are at least making the technical debt apparent and explicit, thus increasing the likelihood you’ll eventually come around to pay it off.

When that glorious day comes, though, it would be nice to get a quick overview of the code’s shortcomings, so that you can decide what to work on first. Getting a list of TODOs scattered over many files sounds like a great task for grep, and a relatively simple one at that. But somehow, every time I wanted to do that I ended up spending some non-negligible time just working out the details of grep‘s syntax and flags.

Thus, the logical course of action would be craft a simple script which would relieve me from doing that ever again. However, when I got around to writing it, I quickly realized the task it’s not actually that simple. In fact, it’s totally impossible to do it with just grep, since it would require matching a regex against multiple subsequent lines of input . Standard GNU grep doesn’t support that at all.

Well, at this point I should’ve probably taken the hint and realize it’s not exactly the best idea to use a shell script here. But hey, not everything has to be written in Python, right? :) So I rolled up my sleeves and after a fair amount of googling (and stack-overflowing), I unleashed a horror that I hereby present:

For best result, it is necessary to have pcregrep installed, which is an extended version of grep that supports the full spectrum of Perl-compatible regular expressions. On most popular Linux distros, pcregrep is just one apt-get install away.