chisquared's comments

On: Fish 4.0: The Fish of Theseus

[chisquared]

> We don't recommend oh-my-fish for various reasons

Care to elaborate a bit on those? Or is it the kind of thing that's impolite to discuss?

On: A visual proof that a^2 – b^2 = (a + b)(a – b)

[chisquared]

There’s no need for this extension: https://news.ycombinator.com/item?id=42425681

[jacobolus → chisquared]

Well the whole point here is that we're doing geometry. If you just want to do symbol twiddling you don't need the picture at all.

On: A visual proof that a^2 – b^2 = (a + b)(a – b)

[chisquared]

If b is negative, define c = -b, and use the linked result to show that

a^2 - b^2 = a^2 - (-c)^2 = a^2 - c^2 = (a + c)(a - c) = (a + b)(a - b)

On: A visual proof that a^2 – b^2 = (a + b)(a – b)

[chisquared]

> Then you've just skipped the case when a^2 - b^2 is negative.

Not really. If b > a, then swap them to conclude that b^2 - a^2 = (b + a)(b - a), which is what the visual proof demonstrates.

Your conclusion is equivalent to saying that a^2 - b^2 = (a + b)(a - b).

On: The walls of Apple's garden are tumbling down

[chisquared]

Steve Jobs would have agreed with you at one point.

I'm not sure what changed his mind (or if he ever even really did), but he also thought that aside from the native apps that came with the iPhone, everything else should just be a web app.

[Repulsion9513 → chisquared]

Or the app store and libs (and apps) weren't ready yet and they wanted to get the iPhone out the door to enjoy being first mover.

On: My First Impressions of Nix

[chisquared]

Huh, is this what Nix users mean by “impure”?

If so, then it makes so much more sense to me now.

[rgoulter → chisquared]

Yes, but 'pure' might mean different things at different levels.

In a programming language, 'pure' would just refer to "function where you get the same output from the same input; no side effects".

In parent's case, there was an 'impurity' such that the package is meaningfully different depending on the machine it was built on.

On: GitHub Packages Is Down

[chisquared]

> Anyone could just change username/organization and break thousands/millions of build.

GitHub redirects you to the new name in the event of a rename and you look up the old one.

[adders → chisquared]

until someone claims the old name as a new org/repo

[JamesonNetworks → chisquared]

For now, hopefully

[naikrovek → JamesonNetworks]

yeah. if GitHub is even real.

[JamesonNetworks → naikrovek]

Well, we know GitHub is real. But we should also remember that they can change their API at anytime and basing a package manager on their priorities is not the best situation for the long term success of that package manager, unless they are owned by Microsoft

On: TabFS – a browser extension that mounts the browse...

[chisquared]

> even package managers like pip

This reminds me of a blog post [1] I read before. Pertinent quote:

> Unbeknownst to me, even with --dry-run pip will execute arbitrary code found in the package's setup.py. In fact, merely asking pip to download a package can execute arbitrary code (see pip issues 7325 [2] and 1884 [3] for more details)!

Also seen on Twitter [4].

[1] https://moyix.blogspot.com/2022/09/someones-been-messing-wit...

[2] https://github.com/pypa/pip/issues/7325

[3] https://github.com/pypa/pip/issues/1884

[4] https://twitter.com/moyix/status/1566561433898426368

On: Problem solving with dimensional analysis

[chisquared]

I was going to say that the title reminded me of these notes I skimmed through ages ago called “Street-fighting mathematics” [1].

Sure enough, the end of the article indicates [1] as the reference.

[1] https://ocw.mit.edu/courses/18-098-street-fighting-mathemati...

On: In the past, I've had students call my problem set...

[chisquared]

Interesting problems!

It’s not hard to intuit the truth values of the conjectures in the first two questions. I don’t have proofs, though.

No idea about the third one.