Jon Skeet

Python gets love for a number of choices it made right early on, and that its core langauge is obviously well thought out. Even very old Python is generally readable and clear; except for some colons, it looks like pseudo-code.

This is the same reason I think Java gets a lot of respect: they had a few core language design ideas and built the language around them. People will say COBOL's syntax is horribly verbose, but you can see what they were trying to do.

So you might dislike those choices, but your critique becomes about the consequences of the choice, which implicitly is something the person making it can't know at the time.

With PHP, people are complaining that users have to live with a whole host of accidents or poorly thought out ideas that are now baked in.

Other languages get criticized for that, too. Python was hammered over their poorly thought out support for unicode in Py3K[4], which blocked many distros from supporting it until around 3.4. (And, generally, most people agreed Python3 was a mess until ~3.6 and the whole transition is widely seen as a case study in what not to do.)

Java gets dislike for similar bad choices. Java's Date class is pretty notorious[2] as a how-not-to. Java arrays are covariant, and it was staring them in the face as they coded the ArrayStoreException[5] to deal with otherwise perfectly valid assignments. But the .NET one-upped them by knowingly making their arrays covariant, despite knowing it was a problem in Java. (Probably to…

Cool library, I'll definitely be looking into this more closely in the future. The automatic handling of ambiguous time during timezone transitions is curious. As an example, Django punts on automatic handling and requires a user to choose between pre and post transition (I wrote the is_dst handling): https://github.com/django/django/blob/19e20a2a3f763388bba9263d56db34012e90cf5b/django/utils/timezone.py#L368

What if you were to begin with a time at 3:30 and then subtract an hour. Would your library properly return 1:30? What if a user had a naive time at 3:30, subtracted an hour, and then converted to an aware time using your library? For what it's worth, I think moving to 3:30 is the correct behaviour in the vast amount of cases. Requiring a user to provide a direction to move and throwing an exception if they don't is dangerous. How often are users going to see this exception, if at all? Just wondering how much you've considered cases, if they exist, that would be better off moving to 1:30.

I'll add one more thing. As soon as I started browsing the page I thought "why would I use this over arrow?". Great to see you addressed that by default. I didn't know about some of arrows shortcomings/bugs, so they were really useful.

Handling dates, times, and timezones in particular is a tricky problem, as evident by the large number of libraries in each language trying to get it right. If you haven't already, I'd really recommend reading the blog posts of Jon Skeet regarding Noda…

Going a little further, what I'd really like to see is the core concepts implemented in a way that allows a standard implementation to follow straightforwardly from the type system, but also allow for doing nonstandard things. Like, "here's a logic language built in" is kind of boring. What's more enticing is "Here are the components. Here's a nominal implementation based on these components. Here's a weird thing you can do that we hadn't actually designed for, but could fit certain use cases."

I remember Jon Skeet did a whole series of blog posts on reimplementing C# async, which was possible because C#'s async syntax isn't bolted to the implementation, and added features like coroutines that weren't part of C# at all. https://codeblog.jonskeet.uk/2011/06/22/eduasync-part-13-first-look-at-coroutines-with-async/. Similarly Daniel Earwicker had a series where he implemented async/await using iterator syntax instead https://smellegantcode.wordpress.com/2010/12/14/unification-of-async-await-and-yield-return/.

And sure, now I know it's all kind of fancy but fairly trivial stuff you can do with monads (and I guess free monads in the Linq-to-SQL case), but it was fascinating to me at the time.

So yeah, for "selling" purposes, I think rather than selling datalog built into the language as a front-page feature, a series of "how to build a datalog" posts would go further in showing off the power of the components of the language that it's built from.

(And FWIW I do like the way…

The problem with SOLID is not SOLID, it's the fetishism that sometimes surrounds it. I get it, rules are attractive as they make everything easier. You put on blinders and follow the track. But the fact that there's so much disagreement about how to best build software, with valid arguments in all sides of the multiple spectra, should hint at its truer nature as a craft (some would say a philosophy, but I haven't yet reached that level of enlightenment) rather than an exact discipline. Isn't it time to perhaps get comfortable with the idea that there are no perfect solutions, only trade-offs and that the right answer is most likely "it depends"? I understand that some people feel protective of their investment at internalizing the various "principles", but learning them doesn't give anyone a license not to think and to mindlessly apply them. And yes, SOLID is mostly useful in its essence, but over time parts of it have caused confusion and have not always aged well (https://codeblog.jonskeet.uk/2013/03/15/the-open-closed-principle-in-review/).

At a more personal level, the DIP section of this article hit close for me, as I've (again) lived the described scenarios a mere week ago. Sometimes `main()` is all you need and all you'll ever need. The extra tooling is also debt. If you choose to incur it, it must palliate to an actual problem that you actually have, else YAGNI.

> The original Java date classes (also from the 1.1 era) were functional and correct, but badly designed. A modern time API was introduced in Java 8 in 2014.

I'm pretty sure they were neither correct nor functional. I've read pretty detailed examples of everything they got fundamentally wrong, which was a lot. Wrong, not as "this is cumbersome to use" but as in "this fundamentally misunderstands what dates are at a conceptual level, and produces wrong results". Unfortunately, I would have to google it now.

All I can find right now is Jon Skeet's summary [1], which leans more to the "avoid using java.util.Date because it's one giant pitfall" side of the argument. Though it does mention some fundamental problems with it. However, this is not the article I found back in the day, which was both more comprehensive and more critical.

> A modern time API was introduced in Java 8 in 2014.

I seem to remember even at that time people were still not recommending Java standard date classes and functions, but I may be misremembering. Or were all the replacements like joda time from a previous era?

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[1] https://codeblog.jonskeet.uk/2017/04/23/all-about-java-util-date/

I do feel your pain with these crappy tutorials, and many of them are glorified blogspam or recycling/reheats of the same thing you could have already found out by reading the docs. There's no depth, no referencing of documentation, very little reasoning about why the thing you're explaining works.

That said...ideally if the author abides by (1) do proper research and (2) "Your tutorial can be reviewed by other brilliant engineers who can point out your mistakes" then there's no reason why you couldn't produce a reasonable quality tutorial in this way.

I think this article is written for developers/engineers who's overall skill level and expertise is a cut above inexperienced folks who're just starting out. i.e. you know how to research, you have a working familiarity with the tech stack you're working with (and broader awareness of other tech stacks), you know how to ask a "good question" on Stack Overflow (or have read and understood Jon Skeet's "Writing the perfect question" article[0]).

It's kinda like taking rubber ducking to the next level and sharing your learning experience.

[0]: https://codeblog.jonskeet.uk/2010/08/29/writing-the-perfect-question/