Right now in a dark and not very windy UK w/ 10GW of gas burners running the spot price for electricity here is almost £150 per MWh, but at 10am it was sunny with a brisk wind and sure enough that spot price was about £25 per MWh. Gee, I wonder whether the wind and sun are cheaper...

To hit 90% the boiler needs to be designed to condense water vapour out of the exhaust gases, this way we'll get back the energy needed to turn water into a vapour which is a large portion of the energy embodied by the exhaust gas. And to do that the vapour needs to pass a low temperature fluid, so we use the input fluid we were about to heat with the boiler anyway, we want this fluid to be cooler than about 55°C but that means if we're using the boiler to heat a home with radiators, rather than to make fresh hot water for cleaning etc. we need our return temperature from the radiators to be less than 55°C which means we need our flow temperature to be lower (than the typical 70-80°C programmed by builders, not lower than 55°©) or else the radiators can't possibly radiate enough heat to hit that number, which means we're actually doing much of the same heating efficiency work we'd have to do to use heat pumps anyway...

I doubt it. C++ does have a huge amount of stuff written by Bjarne - its author - because it appears C++ is the only thing he ever did† and he sure does like writing so that's what all his writing is about. He's written several books about C++, various HOPL papers about C++, as well as numerous proposal papers, speeches, standards documents, letters, all about C++

C++ is also enormous and undisciplined, so while there are a lot of C++ documents there's a lot more of C++ to be documented than most languages and I suspect that out-weighs the volume of documents.

† His PhD thesis is, at least for now, only available for personal inspection and I don't care enough to travel to the holding library and read it, but it seems plausible given the topic and timing that the work for that PhD thesis is also just C++ again, or rather a distant ancestor of C++

"I have not come to bring peace, but a sword."

Which like, you don't need to twist that very hard to get to a place where you're going around "bringing the sword" to people who you think need it...

The Old Testament is big on genocide though, "We should definitely murder these children" has a lot more justification at the start of the book, or if you're batshit and think that stuff about Revelation, right at the end is a concrete prediction of future events then maybe that too.

Connect 4 is a win for the first player

That probably doesn't seem rational but remember loads of these people think the Bible is a true story.

It's obviously not legal for say, me, a middle aged man, to possess a photograph of some 17 year old girl with her tits out. Right? Except well... wait no, because what if I have a photo of my middle aged wife shortly after we first met, so the photo shows a 17 year old girl with her tits out, but the person is my wife, who is like "Yeah, remember when I had long hair? Also, I wish my tits still looked like that". So clearly that is OK after all, it's legal.

And then we have a huge row, she divorces me, now that photo is illegal after all, because I'm definitely not allowed to have photos of under-age girls with their tits out, and now the photo isn't of my wife... not any more.

Knife laws similarly have weird edge cases. 12" long sharp blade? Crime. In a Kebab shop to make delicious kebabs? Legal. I took it with me to the pub after work? Crime; Walking down the street with an ordinary Swiss Army Knife (oversize)? Crime. Tiny version of that knife? Legal. Sword, like an actual medieval sword? Crime. But I need it for this mock battle we're staging? Still a crime. No swords. Use a fake sword which can't hurt anybody or go to jail.

Edited: The "original" Swiss Army Knife is barely short enough that it's always legal, but some oversize variants are not. Like that Kebab knife you can have a lawful reason you needed to carry the knife regardless of size but I hope your reason make sense ("Self defence" is never a lawful reason to carry weapons in the UK)

Like "These Artemis 2 photos were generated by AI" is wrong but "The broadcast footage of the Apollo missions was generated by AI" is incredibly stupid and I want to understand if I'm about to engage with an incredibly stupid opinion.

For example by creating working processes which never end up "accidentally" causing awful outcomes. This is sometimes more expensive, but we should ensure that the resulting lack of goodwill if you don't is unaffordable.

Worst case there is malice and you've now made it more difficult to hide the malice so you've at least made things easier for those who remain committed to looking for malice, including criminal prosecutors.

Deleting that history is good to know about after the fact, but preferably lets just not create the problem.

There's an SF short I can't find right now which begins with somebody failing to return their copy of "Kidnapped" by Robert Louis Stevenson, this gets handed over to some authority which could presumably fine you for overdue books and somehow a machine ends up concluding they've kidnapped someone named "Robert Louis Stevenson" who, it discovers, is in fact dead, therefore it's no longer kidnap it's a murder, and that's a capital offence.

The library member is executed before humans get around to solving the problem, and ironically that's probably the most unrealistic part of the story because the US is famously awful at speedy anything when it comes to justice, ten years rotting in solitary confinement for a non-existent crime is very believable today whereas "Executed in a month" sounds like a fantasy of efficiency.

All ColdStrings which look like 8 bytes of UTF-8 text really are 8 bytes of UTF-8 text, just the type label on those 8 bytes isn't "[u8; 8]" an array of 8 bytes but instead "mut *u8" a raw pointer. "Validate" for example is 8 bytes of ASCII, thus UTF-8, and Rust is OK with us just saying we want a pointer on a 64-bit machine with those bytes. It's not a valid pointer, but it is a pointer and Rust is OK with that, we just need to be careful never to [unsafely] dereference the pointer because it's invalid

OK, so there are two cases left: First, what if there are fewer bytes of text? Zero even?

Since there are fewer than 8 bytes of text we can use the whole first byte to signal how many of the remainder are text, we use the UTF-8 over-long prefix indicator in which the top five bits of the byte are all set, bytes 0xF8 through 0xFF for this, there are eight of these bytes corresponding to our 8 lengths 0 through 7 inclusive. Because it's over-long this indicator isn't itself a valid UTF-8 prefix. Again we can pretend this is a pointer while knowing it's invalid.

Lastly, the seemingly trickiest problem, what if the string didn't fit inline? We use a heap allocation to store the text prefixed by a variable size integer length and we insist this allocation is aligned to 4 bytes. This means a valid pointer to our allocation has zeroes for the bottom two bits, then we rotate that pointer so those bottom two bits are at the top of the first byte position (depending on machine word layout) and we set the top bit. This is now always invalid UTF-8 because it has the continuation marker - the top bit is set but the next is not, which cannot happen in the first byte of any UTF-8 text, and so our code can detect this and reverse the transformation to get back a valid pointer using the strict provenance APIs if this marker is present.

This type is tomtomwombat's idea, credit to them:

https://github.com/tomtomwombat/cold-string*

ColdString is easier to explain, the whole trick here is the "Maybe this isn't a pointer?" trick, ColdString might be a single raw pointer onto your heap with the rest of the data structure at the far end of the pointer, this case is expensive because nothing about the text lives inline, but... the other case is that your entire text was hidden in the pointer, on modern hardware that's 8 bytes of text, at no overhead, awesome.

CompactString is more like a drop-in replacement, it's much bigger, the same size as String, so 24 bytes on modern hardware, but that's all SSO, so text like "This will all fit nicely" fits inline, yet the out-of-line case has the usual affordances such as capacity and length in the data structure. This isn't doing the "Maybe this isn't a pointer?" trick but is instead relying on knowing that the last byte of a UTF-8 string can't have certain values by definition.

I've seen exactly one Rust type which is actually a union, and it's a pretty good justification for the existence of this feature, but one isn't really enough. That type is MaybeUninit which is a union of a T and the empty tuple. Very, very, clever and valuable, but I didn't run into any similarly good uses outside that.