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Comment by snprbob86 | Hacker News Reader

How does that new hip saying go? "WAT?"

https://github.com/twitter/time_constants - Time constants, in seconds, so you don't have to use slow ActiveSupport helpers

Seriously?? Just look at the freaking source code: https://github.com/twitter/time_constants/blob/master/lib/ti... - Luckily, it appears that it is generated.

I realize that Ruby is slow and all (we experience it daily), but holy crap people. I also realize that Twitter is a mega scale business, but at what point does this kind of library become a good idea?

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I see absolutely nothing wrong with this. It replaces a slow way to write human-readable intervals with a fast way. How is that a bad thing?

Because it is wrong. Time is a difficult problem to solve, it doesn't move at a constant rate, the length of days and years change. You simply cannot set a constant and have it be "correct".

It may be more performant to set time ranges as constants, but you will get in to trouble unless you know exactly what you are doing. The people at Twitter who wrote the code will be aware of the trade-offs they have made, but what happens when Jo Random developer forks it on GitHub without thinking it through because "it's fast and Twitter use it - it must be good!"

For example:

    T_1_MONTH = 2592000

Not all months have 30 days.

    T_1_SOLAR_YEAR = 31558150

A solar year, is (roughly) 31556925.25218 seconds[1].

[1]http://www.wolframalpha.com/input/?i=seconds+in+a+solar+year

Just by the mere fact that these are constants documented to be in seconds, it's clear that they shouldn't be used for sensitive or precise time calculations. If you're at the point where you don't realize this, you probably aren't going to be able to use a full-featured time library correctly, either.

"Difficult for novices to use incorrectly" is a good feature for code to have, but it's not the highest good, and its absence does not mean that the code is bad.

How many time constants could possibly be in their code base? A few dozen?

Instead of writing `foo(3.days)` they are writing `foo(T_3_DAYS)` with this library. Instead, why not just create a constant `BAR_DURATION = 3.days.in_seconds` and then write `foo(BAR_DURATION)`.

Problem solved.

You can still assign these values to semantically-named variables where appropriate, with the bonus of not having to monkey-patch ints just to define a few dozen constants.

It's benign, boring utility code, I just don't get what's offensive about it.

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