I started in C and switch to C++. It’s easy to think that the latter sort of picked up where the former left off, and that since the advent of C++11, it’s unfathomably further ahead. But C continues to develop and occasionally gets some new feature of its own. One example I can think of is the restrict key word that allows for certain optimizations. Afaik it’s not included in the C++ standard to date, though most compilers support it some non-standard way because of its usefulness. (With Rust, the language design itself obviates the need for such a key word, which is pretty cool.)

Another feature added to C was the ability to initialize a struct with something like FooBar fb = {.foo=1, .bar=2};. I’ve seen modern C code that gives you something close to key word args like in Python using structs. As of C++20, they sort of added this but with the restriction that the named fields have to come in the same order as they were originally defined in the struct, which is a bit annoying.

Over all though, C++ is way ahead of C in almost every respect.

If you want to see something really trippy, though, have a look at all the crazy stuff that’s happened to FORTRAN. Yes, it’s still around and had a major revision in 2018.

I guess the MAC address guy is up next. 48 bits may not go so far if every light bulb is going to want its own.

Imagine if you were the guy who made the call on IPv4 addresses…

Falsehoods About Time

Having a background in astronomy, I knew going into programming that time would be an absolute bitch.

Most recently, I thought I could code a script that could project when Easter would land every year to mark it on office timesheets. After spending an embarrassing amount of…er…time on it, I gave up and downloaded a table of pre-calculated dates. I suppose at some point, assuming the code survives that long, it will have a Y2K-style moment, but I didn’t trust my own algorithm over the table. I do think it is healthy, if not essential, to not trust your own code.

Falsehoods About Text

I’d like to add “Splitting at code-point boundary is safe” to your list. Man, was I ever naive!

Fair, though I guess my interpretation was that void* is kind of like a black hole in that anything can fall into it in an unsettling way that loses information about what it was?

So you’re saying the comments themselves get cached on the local instance where the user is registered before being synced with the remote community-hosting instance?

I honestly don’t know how these things work internally, but had assumed the comments needed to go straight to the remote instance given the way you can’t comment once said instance goes down? You can still read the cached content though.

When I first heard the term “fediverse”, it immediately made me think of some sort of vast interplanetary network. And let’s face it: a fediverse-like model is really what you would need if you had settlements scattered throughout the solar system. A monolithic, centralized service would be awful, given the reality of communication lag and likely limited bandwidth.

So let’s say lemmy (or more generally activitypub) were to go interplanetary. How would that work out? You set up your first instance on Mars. Any content that’s posted there will be immediately available to your fellow Martians. Earthlings who subscribe may also be able to view it as their instances cache the content, albeit after some delay.

But the trouble starts when Earthlings want to start contributing to the discussion. If they have to wait the better part of an hour to get a single comment lodged, it’s going to get old fast.

So you would need to allow the Earth side to branch off to some extent from what’s happening on Mars. Then eventually, something like a git merge would try to bring it all back together? I wonder if that would work?

Actually, now that I think of it, there’s no reason you need to join the 2 names into a single str. You could just leave it as a tuple of last, first and Python will know what to do in comparing them.

>>> sorted(student_ids, key = lambda i: ((rec := student_recs[i])['last'], rec['first']))
[632453, 1261456, 532153]

So the lambda would be returning ('Potter', 'Harry') rather than 'Potter, Harry'. But whatever. The := part is still the same.

Can you use it to initialize vars outside the scope of the lambda?

No, that’s not what it’s for. It lets you define a temporary local variable within an expression. This is useful in situations where you might want to use the same value more than once within the expression. In a regular function, you would just define a variable first and then use it as many times as you want. But until the walrus operator came along, you couldn’t define a variable within a lambda expression.

Can you give an example?

Ok, I’m trying to think of a simple example. Let’s say you had a database that maps student IDs to records contain their names. To keep things simple, I’ll just make it plain old dict. And then you have a list of student IDs. You want to sort these IDs using the student names in the form “last, first” as the key. So you could go:

>>> student_recs = {1261456: {"first": "Harry", "last": "Potter"}, 532153: {"first": "Ron", "last": "Weasley"}, 632453: {"first": "Hermione", "last": "Granger"}}
>>> student_ids = [1261456, 532153, 632453]
>>> sorted(student_ids, key = lambda i: (rec := student_recs[i])['last'] + ', ' +  rec['first'])
[632453, 1261456, 532153]

The problem here is that student_ids doesn’t contain the student names. You need use the ID to look up the record that contains those. So let’s say the first ID i is 1261456. That would mean:

rec := student_recs[i]

evaluates to:

{"first": "Harry", "last": "Potter"}

Then we are effectively going:

 rec['last'] + ', ' + rec['first']

which should give us:

 'Potter, Harry'

Without the := you would either have to perform 2 student_recs[i] look-ups to get each name which would be wasteful or replace the lambda with a regular function where you can write rec = student_recs[i] on its own line and then use it.

Am I making any sense?

They’re somewhat more capable now that we have the walrus (:=) operator.

One thing most text editors can do is print. I was shocked the other day when I couldn’t print a readme from vscode when someone asked for hard copy.

This is why I fear activating any AI features in the IDE.

Compiler/interpreter: Can’t find variable farfignewton.

Earlier:

Me: Declare variables near, far

IDE: Oh! You mean farfignewton right? I found that in some completely unrelated library you didn’t write. Allow me complete that for you while you’re not paying attention.

This was a struggle for me going from hobbyist programmer to working at a company. I tried to tone it down. Really. But eventually I got “promoted” to having my own office with a suspiciously thick door. Hmm…

True story. I was looking for an answer to an obscure problem and found it in a 10-year-old stackoverflow post. Then I looked more closely at the author…

Hey! Me from 10 years ago, stop being such a smart ass! It’s obnoxious.

There is an issue with templated code where the implementation does have to be in the header as well, though that is not the case here. C++20 introduced modules which I guess were meant to sort out this mess, but it has been a rocky road getting them to be supported by compilers.

Looks like we’ve got a Java programmer here taking C++ for a spin.

There is bounds checking, but it’s opt-in. I often enable it on debug builds.

Ah I think I found it. I need to go:

{
    "format_on_save": "off"
}

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