The Computer And General Tech Thread - Software, Hardware, Questions, etc.

[rotting bones]

There are trade-offs between space and time complexity.

The complication here is with Unicode canonical equivalence. The example here is as follows:
A sequence of n copies of U+07F3 is canonically equivalent to a sequence of n copies of U+07F1 followed by n copies of U+07F2. Thus, with the requirement that the set of strings recognized is closed under canonical equivalence, /\u07F3*/ is not a regular expression (since it matches strings of the form aⁿbⁿ for all n)

As far as I'm aware, this level of Unicode-awareness is not generally found it regex engines

If I understand this correctly, it seems to violate the assumption of strings in a fixed alphabet. You can't define arbitrary strings to be equivalent to other strings, and still expect everything else to work. Otherwise, I could define the string "a" to be equivalent to the solution of some arbitrary problem X, giving me a universal solver.

[Richard W]

There are trade-offs between space and time complexity.

The complication here is with Unicode canonical equivalence. The example here is as follows:
A sequence of n copies of U+07F3 is canonically equivalent to a sequence of n copies of U+07F1 followed by n copies of U+07F2. Thus, with the requirement that the set of strings recognized is closed under canonical equivalence, /\u07F3*/ is not a regular expression (since it matches strings of the form aⁿbⁿ for all n)

As far as I'm aware, this level of Unicode-awareness is not generally found it regex engines

If I understand this correctly, it seems to violate the assumption of strings in a fixed alphabet.

Yes. If you think of a monoid (semigroup with a (distinguished) identity) of strings in a fixed alphabet, then there is a moderately well known generalisation that allows some pairs of letters in the alphabet to commute. This is known by various names - trace monoid, free partially commutative monoid, independence monoid. A key point is that a process that is compliant to the Unicode Standard shall not deliberately yield different results for canonically equivalent strings. Now there is a theorem (Sakarovitch, 1992) that says it is undecidable as to whether a rational expression (one formed by union, concatenation and Kleene star) in Unicode characters defines a regular expression for the trace of Unicode strings under canonical equivalence.

[Raphael]

I just discovered how to modify the "New posts" link in the ZBB's "Quick links" menu to show individual posts instead of threads:

https://www.verduria.org/search.php?sea ... mit=Search

I'm posting about that here because figuring this out made me somewhat happy, but not happy enough to justify a post in the Happy Things Thread. Also, I'm somewhat unhappy about how many of the newest posts on the ZBB were written by me. Hopefully, having this tool at hand in the future will help me keep myself under control better.

Minor neurolinguistic note: when I wrote the first sentence of this post, at first I mistyped "individual" as "in dividual". I seriously wonder what my brain was thinking when I did that.

[WarpedWartWars]

Minor neurolinguistic note: when I wrote the first sentence of this post, at first I mistyped "individual" as "in dividual". I seriously wonder what my brain was thinking when I did that.

Apparently "dividual" is a word, albeit an archaic one.

[Travis B.]

Minor neurolinguistic note: when I wrote the first sentence of this post, at first I mistyped "individual" as "in dividual". I seriously wonder what my brain was thinking when I did that.

Apparently "dividual" is a word, albeit an archaic one.

Dividual is sufficiently archaic that I wouldn't consider it part of the English language as spoken by the vast majority of people today.

[Rounin Ryuuji]

Yet it's still comprehensible enough I wouldn't say it isn't English. One of the citations on Wiktionary is from a book I've read twice, and the meaning was quite clear from context.

[WarpedWartWars]

Yet it's still comprehensible enough I wouldn't say it isn't English. One of the citations on Wiktionary is from a book I've read twice, and the meaning was quite clear from context.

I see only one quote:

the moon … her reign with thousand lesser lights dividual holds
— John Milton

[Rounin Ryuuji]

Yet it's still comprehensible enough I wouldn't say it isn't English. One of the citations on Wiktionary is from a book I've read twice, and the meaning was quite clear from context.

I see only one quote:

the moon … her reign with thousand lesser lights dividual holds
— John Milton

"1895, George MacDonald, Lilith‎[1]:

She began to moan, and sigh deep sighs, then murmur as holding colloquy with a dividual self: her queendom was no longer whole; it was divided against itself."

[Travis B.]

I retroactively erased all binaries from my zeptoforth repository, since they were making git clone take a whole lot of time and bandwidth, and the binaries are in the zeptoforth release tarballs anyways.

[Travis B.]

I have decided I should create a basic emulator for ARM Cortex-M for generating binaries with rather than slowly burning out the flash on my boards doing so (I already burned out one of my boards, a Raspberry Pi Pico, but thankfully it was easy to replace, which is not the case for my other boards). This is going to be a pain to write, but I've already written a disassembler for ARM Cortex-M, so writing an emulator shouldn't be that much more difficult (especially since I am not going to be implementing all the functionality, such as interrupts).

[Raphael]

Now who could have predicted this?

"Apple AirTags, touted as a way to find lost keys, purses, also are being used by stalkers"

(Chicago Sun-Times)

https://chicago.suntimes.com/2022/5/27/ ... ago-police

[Travis B.]

I have a new job - unpaid tech support! Normally this is something I would not be too happy about, but in this case I am fine with it as enough users are interested in using zeptoforth that I now have had people asking for help using zeptoforth. And this has had useful results, e.g. currently zeptoforth sends XON and XOFF characters, which haven't appeared in terminal windows on my machine, but which someone else had appearing in their terminal windows, which I would not have found out had they not asked me for help getting zeptoforth up and working.

[Travis B.]

Now who could have predicted this?

"Apple AirTags, touted as a way to find lost keys, purses, also are being used by stalkers"

(Chicago Sun-Times)

https://chicago.suntimes.com/2022/5/27/ ... ago-police

The thing is they just came out with an article about this now? I was hearing about this a good ways back, this is not new news at all.

[Raphael]

Oh, sorry, I didn't know that. In fact, I've only now learned what the things are.

[bradrn]

I have a new job - unpaid tech support! Normally this is something I would not be too happy about, but in this case I am fine with it as enough users are interested in using zeptoforth that I now have had people asking for help using zeptoforth. And this has had useful results, e.g. currently zeptoforth sends XON and XOFF characters, which haven't appeared in terminal windows on my machine, but which someone else had appearing in their terminal windows, which I would not have found out had they not asked me for help getting zeptoforth up and working.

You’ve got me curious now… how does a program accidentally send characters to stdout? I’ve never heard of a bug quite like that.

[Travis B.]

Oh, sorry, I didn't know that. In fact, I've only know learned what the things are.

No need to apologize.

[Travis B.]

I have a new job - unpaid tech support! Normally this is something I would not be too happy about, but in this case I am fine with it as enough users are interested in using zeptoforth that I now have had people asking for help using zeptoforth. And this has had useful results, e.g. currently zeptoforth sends XON and XOFF characters, which haven't appeared in terminal windows on my machine, but which someone else had appearing in their terminal windows, which I would not have found out had they not asked me for help getting zeptoforth up and working.

You’ve got me curious now… how does a program accidentally send characters to stdout? I’ve never heard of a bug quite like that.

I was deliberately outputting XON and XOFF characters so that software that uses software flow control could take advantage of them. Also, on my machine they seem to be completely invisible to the user. However, on someone else's machine it was printing out 0x0013 code point blocks for the XOFF characters for reasons beyond me. So I decided to disable XON and XOFF by default in the latest zeptoforth, release 0.36.5, even though they can still be turned on if the user so desires.

[bradrn]

I have a new job - unpaid tech support! Normally this is something I would not be too happy about, but in this case I am fine with it as enough users are interested in using zeptoforth that I now have had people asking for help using zeptoforth. And this has had useful results, e.g. currently zeptoforth sends XON and XOFF characters, which haven't appeared in terminal windows on my machine, but which someone else had appearing in their terminal windows, which I would not have found out had they not asked me for help getting zeptoforth up and working.

You’ve got me curious now… how does a program accidentally send characters to stdout? I’ve never heard of a bug quite like that.

I was deliberately outputting XON and XOFF characters so that software that uses software flow control could take advantage of them. Also, on my machine they seem to be completely invisible to the user. However, on someone else's machine it was printing out 0x0013 code point blocks for the XOFF characters for reasons beyond me. So I decided to disable XON and XOFF by default in the latest zeptoforth, release 0.36.5, even though they can still be turned on if the user so desires.

Ah, I see; thanks for explaining!

[Ryusenshi]

I wanted to try a version of Unix on my laptop. But a pure command-line interface sounds a bit daunting. So, I went with GhostBSD, a variant of FreeBSD that includes the MATE desktop environment. It works nicely. But, since I've been using MATE for years with Linux Mint... it's almost too familiar: as long as I'm not using the terminal, I barely feel that I'm using a different OS.

[Travis B.]

I wanted to try a version of Unix on my laptop. But a pure command-line interface sounds a bit daunting. So, I went with GhostBSD, a variant of FreeBSD that includes the MATE desktop environment. It works nicely. But, since I've been using MATE for years with Linux Mint... it's almost too familiar: as long as I'm not using the terminal, I barely feel that I'm using a different OS.

Of course this is because overall Linux and xBSD are very similar, and where they do differ is most apparent at the command line and things like system initialization (e.g. xBSD does not use systemd), so if you have been using Linux Mint with MATE for years you probably won't see much of a difference from FreeBSD with MATE.