ash

I haven't tried Flow. But there were a couple of practical things that influenced my decision when choosing between Flow and TypeScript:

* TypeScript has larger community.

* Flow requires Babel. TypeScript doesn't. One less dependency to worry about. And in my experience TypeScript compiler produces better JavaScript than Babel.

* Flow is written in OCaml. It could probably make it more difficult to install than TypeScript.

P.S. React works fine with TypeScript. I haven't played with React Native though.

Why would you need to care about portability? Do people use terminals that are incompatible with xterm?

What is DBX?

I was confused about libsodium/NaCl APIs, specifically crypto_sign vs crypto_auth. The difference:

1. `crypto_auth` is for secret-key signatures (auth): https://download.libsodium.org/doc/secret-key_cryptography/s...

2. `crypto_sign` is for public-key signatures: https://download.libsodium.org/doc/public-key_cryptography/p...

And tptacek is arguing secret (symmetric) key is preferable: https://news.ycombinator.com/item?id=13866983

Note: redirect to auto-playing YouTube video. Please add "[video]" to the title.

Side note, looking from the other side of the Atlantic.

I find it crazy that in US you can have 95-page law-like document (in a tiny-font!) produced by executive branch. [1] Especially if a different administration can easily cancel it.

Why doesn't Congress produce these instead?

Related: 380-page "Stream Protection Rule". [2] Canceled? [3]

I wonder how many pages are in the whole corpus of laws and executive rules currently in effect in the US.

[1]: https://www.gpo.gov/fdsys/pkg/FR-2016-11-18/pdf/2016-27540.p...

[2]: https://www.gpo.gov/fdsys/pkg/FR-2016-12-20/pdf/2016-29958.p...

[3]: https://www.congress.gov/115/bills/hjres38/BILLS-115hjres38e...

Original post: https://judithcurry.com/2017/02/04/climate-scientists-versus...

Other people indeed chimed in on your question in other comments. But here's my take about the most important fish features:

* Instant auto suggestions, you just type stuff, like in a web browser.

* Sane defaults, no need to bring around your own config. On a new machine I just install fish, run fish_config and customize the prompt with the web UI.

* Scripting with simple syntax, especially for one-liners. Yes, fish is incompatible with bash, but it's less of issue in this case.

I'm not trying to explain, because I don't know. But the story was posted before:

https://news.ycombinator.com/item?id=13040737 (22 points, 52 days ago)

And first mentioned in the relevant thread 141 days ago:

https://news.ycombinator.com/item?id=12377286

For those wondering,

OBS: https://en.wikipedia.org/wiki/Open_Build_Service

PPA: https://en.wikipedia.org/wiki/Personal_Package_Archive

Article mentions "RPG" many times: "RPG back-end", "RPG developer". For those who wonder what it it (like me), it is not a "Role Playing Game", it is IBM RPG language: https://en.wikipedia.org/wiki/IBM_RPG

> Japan has religious minorities; you might sensibly predict life is difficult for them; you might sensibly predict this implies that e.g. no Japanese PMs come from religious minorities; you got one of those two predictions correct.

Which of those two predictions are correct?

Wow, your calculations are totally awesome (and seem correct)!

It looks like our estimation of "Hyperloop thermal expansion problem solution" feasibility now comes down to your last sentence:

> I wasn't able to find cost figures for roller bearing capable of handling a 36 ton load.

I don't know, railroad car steel wheel? Max load per axle for train cars: 26 - 40 ton. Searching on alibaba.com for "train car wheelset" and "train car bogie" never comes up with more than $2500 per piece. Maintenance seems doable, if we look at millions of train car running around the planet.

> These are the questions that would need to be answered by a hyperloop proponent, not me. The burden of proof is on the person making the claim. The only claim I'm making is that no one has proposed a solution. The two sentences that the Hyperloop white paper devotes to this issue is not a solution.

Yeah, I agree with that sentiment. Luckily, we are not the people making an actual practical decision on Hyperloop. Like you said, we are just trying to get our minds off politics.

> Not even remotely feasible. You would need to have bearings at each column. Friction slip joints would introduce way too much stress.

That's the kind of discussion I'd love to have! Of course, you need linear bearings [1] at each column. But what kind of bearings? Ball or roller bearings? [2] Plain/solid bearings? [3] Something else? What are the forces the tube would produce while expanding? What would be the linear expansion speed? What bearings would be able to sustain those speeds and forces? Would the tube and the pillars be able to sustain them? Do bearings with necessary parameters even exist? How expensive would they be? So on and so on.

Unfortunately, I haven't seen such discussion yet. I could try doing the calculations myself (starting at [4], for example). But I'm afraid I would make some silly newbie mistake in the process.

> Remember: the tube is not only moving hundreds of meters at the ends, it's moving >>1m along (very nearly) its entire length.

Yes, of course the tube is moving by hundreds of meters along most of its length. The questions are: how fast? with what load against the pillar?

[1]: https://en.wikipedia.org/wiki/Linear-motion_bearing

[2]: https://en.wikipedia.org/wiki/Ball_bearing

[3]: https://en.wikipedia.org/wiki/Plain_bearing

[4]: http://www.pbclinear.com/Blog/Calculating-PV-for-a-Plain-Bea...

I've already quoted it in my very first comment in this thread.

You could argue that writing "pillars which constrain the tube in the vertical direction but allow longitudinal slip for thermal expansion" and "slip joints at stations…" is not detailed enough. I've concluded this "longitudinal slip" means some kind of linear bearing on top of each pillar, where straight tube could slowly move without constraints in the direction of the cumulative thermal expansion, while being constrained vertically.

      v    v
    -------------
     tube
    -------------
      ^    ^
      |    |
      |    |

After thermal expansion:

      v    v
    -------------
            tube
    -------------
      ^    ^
      |    |
      |    |

(Note how "tube" sign written on the tube has moved past two pillars.)

Leancrew author missed the "longitudinal slip" part, because most of the article proves that thermal expansion accumulates. Of course it does! Thus the "longitudinal slip" solution.

Yes, Hyperloop paper could be more detailed and more clear. Indeed, it confused leancrew author.

Do you anyone knowledgable (in mechanical engineering?) who could comment on "longitudinal slip" solution? How feasible is it?

This quote is from the first part of the paper for which Musk "apologize[s] in advance for my loose use of language and imperfect analogies". It's just an intro.

The later parts of Hyperloop paper are more precise. I've already quoted "longitudinal slip for thermal expansion" from section 4.2.3. And, unfortunately, leancrew.com article author missed the proposed solution for the problem they spent many words talking about.

> If the tube at the station is moving 100m then the tube near the station is moving 100 meters minus epsilon.

Yes, of course. I agree that the problem of 100m thermal expansion is real and needs to be solved. And I'd like some arguments about why won't Hyperloop "longitudinal slip" solution work (where tube could freely move past the pillars).

Why do you keep posting this article? It can't be a critique of the free "longitudinal slip" linear bearings proposal, because the author assumed the tube is rigidly attached to the pillars. (And it is not.)

Yes, I'm aware of this post. Unfortunately, its author failed to discuss the solution from the Hyperloop paper. The author incorrectly assumed the tube is attached rigidly to the pillars and then proceeded to criticise this wrong assumption.

Could you please show why very-low-speed, low-precision linear bearing to "allow longitudinal slip" of the tube past the pillars, is not "even remotely close to being viable". It's an honest question. I know very little about bearings, but I have yet to find a serious discussion about it anywhere.

I agree with your point #1, but your point #2 makes very little sense. Yes, thermal expansion problem solution from the original Hyperloop paper [1] is yet to be proven to work in practice. For one, nobody has built long enough straight tube for the thermal expansion problem to matter.

However, I don't see how the difference in thermal swings between California and Dubai matters. The proposed solution probability of success or failure should be the same no matter what are the thermal swings. We are talking about (maybe?) 300 meters vs 500 meters per day of expansion for the same tube length. And Dubai - Abu Dhabi route length is much shorter than SF - LA, as you've correctly noticed.

[1]: "The tube will be supported by pillars which constrain the tube in the vertical direction but allow longitudinal slip for thermal expansion <…> Specially designed slip joints at stations will be able to take any tube length variance due to thermal expansion."(http://www.spacex.com/sites/spacex/files/hyperloop_alpha.pdf, page 28, section 4.2.3)

I had switched from Zoho to Yandex about a year ago. For two reasons: 1. Yandex has infinitely more usable web client. 2. Email forwarding that actually works. Every couple of months Zoho decided to stop forwarding for some weird reason. I had to re-enable it through its unusable web interface, every time.

> … it's not possible to export your users data. You can't export emails, password hashes.

Could someone provide details on email/password export from Firebase? This limitation seems very critical.

PBR == Physically-based rendering?

A few months ago I compared different Vim plugins for VSCode and found amVim to be the best for my needs. It's not without its bugs and limitations, but it's good enough:

https://github.com/aioutecism/amVim-for-VSCode

VSCodeVim was not that good at that time, but I haven't checked it recently for a fresh comparison. So make sure to also check out VSCodeVim in addition to amVim.

I was born in the city of Severomorsk.¹ Current population 50,000+. I'm living in another city now. And I can't go the place of my birth unless I prepare the papers two weeks before the visit.² Forget about the spontaneous visits to my friends living there.

¹ https://en.wikipedia.org/wiki/Severomorsk

² My friend helped me with the papers. I don't remember exactly, but simply saying "I want to visit my friends" is not enough. It's more complicated than that.

Some previous submissions:

* https://news.ycombinator.com/item?id=12052856

* https://news.ycombinator.com/item?id=12052525

"If you prefer not to use Tabs, you can disable them through the workbench.editor.showTabs setting."

From the video:

> No country has ever left the European Union before and hasn't used article 50.

I'm not sure about article 50, but Greenland left the EEC (EU predecessor) in 1985.

https://en.wikipedia.org/wiki/Withdrawal_from_the_European_U...

> Me, I wait for Python 5 (=2+3) which will be able to import Python 2 modules, so that you can gradually convert your code to the newer version.

Thank you for saying this! For those interested in this direction, there was a discussion about it on HN a couple of months ago:

https://news.ycombinator.com/item?id=10823406

Proof-of-concept examples embedding Python interpreters within themselves:

https://gist.github.com/dutc/eba9b2f7980f400f6287

https://gist.github.com/dutc/2866d969d5e9209d501a

It's a valid concern. The solution is to wrap the whole script in a bash function executed on the last line.