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Comment by hnriot | Hacker News Reader

Google is by far the best "comment"

Are you saying people should google regular expressions? in my experience (correct me if I'm wrong) that doesn't work, I've never been able to get google to return relevant results even with quotation marks.

Agreed, Google fails at this, however alternative search engines,

http://searchco.de/?q=%5B+-~%5D+ext%3Apod&cs=on http://symbolhound.com/?q=%5B+-~%5D

Symbolhound gives the answer quite well, and searchco.de has some examples of its use in the results.

I'm saying that usually comments are either wrong or out of date, developers code one regex, comment it, then fix a bug later and don't, then there's a discrepancy between the comment and the code. It's nearly always easier to just google the code and see what it does, if (as in this case) it's not obvious.

or make a function regexMatchingAllPrintableASCIIChars() and have it return the regex.

Your response doesn't address what citricsquid said, googling for a regex will almost never return helpful results.

Google regex and you'll find plenty of resources including tools to testing patterns. You won't find much for any specific pattern but read the docs and it will be apparent what this regex does. Familiariy and competence with regex is a basic component of being a developer.

Search "[ -~]" (with or without quotes) to see how good Google's comment is.

The only ambiguous thing about this regex is knowing what's between space and tilde. Otherwise this is a pretty ordinary regex.

The only thing ambiguous about it is most of it?

Not that I agree with the "expect people reading your code to Google things" mindset, but to be fair the only ambiguous thing is the ASCII table which is Googleable.

Hey, might just be me. I'm usually the 'Ben, can you help me with a regular expression' guy over here, but I stumbled, hard, and failed to connect the '-' with a range of characters (probably because I never thought of 'space to .. something').

So I read the snippet, thought 'Yeah, a character class of space, -, ~' and fell on my face in the next couple of lines.

Yeah, I should've known better, I know how to read it. If .. I invest the time and don't glance over a construct and hope to just get it instantly.

I wouldn't want to see this in a code base without proper documentation (be it a comment, a function name or whatever. Something).

There is one author of the code, and potentially many readers.

That one author is the only person who knows what s/he is trying to achieve.

That author taking a few minutes to add some comments will save other people the time to search for answers and the time it takes to grok everything.

The best code is readable. Readability includes comments. If you're going to comment anything in your code at all, RegExes should be at the very top of that list.

Even if I can figure out what the regex matches (with Google or something else), that doesn't necessarily tell me WHY I'm matching on that particular pattern, or why I needed a RegEx in this spot, or what the intent was at the time of writing it.

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