Brian Kernighan adds Unicode support to Awk
github.com
github.com
(Around 7-8 minute mark)
Update:
At 24-25 minute mark, he talks about the technologies he is inquiring to write his new book with (he mentions troff and groff).
He says he wanted to try "XeTeX" (which supports Unicode) but "...I was going to download it as an experiment and they wanted 5 gigabytes and 5 gigabytes at the particular boonies place I'm living would...mmm..not be finished yet!"
So there we go...We had the opportunity to read the mind of the developer of awk and unix and co-author of the literal "C Programming Language", confronting with the absolute state of the tooling of the modern world.
Man, I think once you're Kernighan there should be like a 1gigabit/sec symmetric circuit wherever you go just in case you use it to do something else useful.
But if you want to have every macro package that everyone everywhere likes, you're going to use some space.
There may be some technical reason why this isn't practical. Anyone know, offhand?
But the reason I don't use it is because I don't always have Internet when I need to write my document. I'd rather download all the packages and their documentation beforehand.
It’s just that the distros also include oodles of (plain text!) macro packages for everything under the sun. There are some legitimately large things such as fonts, but generally speaking a full TeXLive or MiKTeX distribution is bloat by ten thousand 100-kilobyte files, like a Python distribution with the whole of PyPI included.
If you know what you want, you can probably fit a comprehensive LaTeX workbench in under 50M, but it takes an inordinate amount of time.
> a manual source port to a different language is painful enough that nobody tried
there are in fact quite a few, many of which are complete: https://tex.stackexchange.com/questions/507846/are-there-any...
Besides, where would you put the bar for “distinguished”? Who would take the decision?
Which should make the problems of any such system obvious: it inevitably becomes yet another “in club” for people with connections and power.
Grand prizes with honorariums and perks of various kinds are a longstanding tradition with value.
I was mostly kidding, but: Kernighan totally can afford a big internet connection wherever he is. But he chooses not to buy it. The social benefit from him having one likely outweighs the personal benefit from him buying it.
Of course, if I still operated internet access and Kernighan was in my area, I'd definitely comp him a circuit. :P
I wonder what distro or editor he is using...
"MacTeX installs TeX Live, which contains TeX, LaTeX, AMS-TeX, and virtually every TeX-related style file and font. [...] MacTeX also installs the GUI programs TeXShop, LaTeXiT, TeX Live Utility, and BibDesk. MacTeX installs Ghostscript, an open source version of Postscript."
Which is, as you say, considerably more than just "XeTeX".
(Also those are universal binaries containing both Intel and ARM versions which probably adds some heft.)
Heh, I remember when "universal binaries" meant "PowerPC and Intel". Different universes ….
Hah, TeX Live is... not that.
It's been enormous since I installed it off a CD in the 90s. The idea, and it works, is that you can just compile anyone's stuff out of the TeX ecosystem.
There is just... a lot... in it. You don't need a package manager if you install the whole universe locally. Like I said: not what I would call a modern approach to tooling.
On the other hand, I have latex files from the mid-Noughties and, I don't even need to check: they'll compile if I want them to.
But yeah, if you want just a little piece of TeX here and there, you're off the beaten track. That's not how TUG rolls.
It also seems quite slow to update, and a recent (?) name change of `tools' to `latex-tools' seems to have broken multicol, which drove me to MikTeX. Internet connection required, but far less headache.
More modern approach: "hey, we have a lot of disk space, we can install everything locally".
Even more modern approach: "hey, we have fast Internet access, we only have to install stuff when we need it".
A full install means installing ~4000 packages, including their source files (tens of thousands of tex files) and built documentation (thousands of PDF files) and hundreds of free fonts (otfs, ttfs, texs own format).
This is huge (>7GB, not just the 5 GB claimed here).
However, you don't need 99 % of this for any given document.
Not installing the source files and documentation PDFs will alone reduce the size by roughly half.
Only installing the packages you really need from a minimal installation gives you a few hundred megabytes at most for even complex documents.
It's a bit annoying to get the list of packages needed though, since there is not really any working dependency management.
I wrote a python wrapper around the tex live installer [1] to make this easy for CI jobs, see e.g. [2].
On a side note: I'd recommend luatex over xetex.
- [1] https://github.com/maxnoe/texlive-batch-installation/
- [2] https://github.com/pep-dortmund/toolbox-workshop/blob/8b00f0...
Sounds like someone should just create a wrapper that catches file opens of uninstalled dependencies and automatically downloads them on the fly.
[EDIT: And in fact, if a cousin comment is to be believed, TeX Live also allows this kind of installation! https://news.ycombinator.com/item?id=32535521]
It’s mostly a death by a thousand cuts thing.
MikTeX, which is available for Mac and Linux as well as Windows will do on-demand downloading of packages and is probably my recommendation for a new installation.
A lot of the drawbacks to TeX stem from to trying to meet the combined requirements of computing platforms of the 1970s–1990s. All input files effectively live in a single namespace so you cannot have two input files with the same name (the same applies to coding where you have a single namespace for all your commands as well).
I recall I managed to cut MiKTeX down to about 12MB. Never heard a single complaint about it.
Well, I've been using groff on and off for a few years, I can give it a shot. Most "macros" as in TeX, are invoked by having the first character of a line be a `.` and then as in TeX, refer to a name. Now, macros in groff are weird. Macros are not delimited by `{}` delimiters as in TeX, but either by having an environment block like so:
.TS
.TE
.NH 1
Some heading here
.PP
Start of a paragraph.
.EQ
f ( x ) ~=~ x sup {2} - 1
.EN
Groff also does pictures, so you can for example create a box with some text in it (it is capable of more, like strokes, macros, color, and I believe rotation[not sure]). To start a picture, `.PS` and `.PE` will do so, and again, a small language as input in that block.
Now, to print anything you should know the design of the original troff system was heavily based on the UNIX philosophy, which means the output you get from running the groff program prints the output to stdout. Just redirect the output to a file to get a PDF or a PS document.
Obviously, there is much I have not covered in this comment, such as macros, registers, and other exciting topics such as refer(1), but this should give you a quick start.
I didn't know about '\&' as a way to "short circuit" groff from interpreting something as a macro that should be literal (such as a line-initial period). That's great to know.
I've found a couple of resources that have been helpful. Mostly, I've been referring to this[0] page on gnu.org. I've also learned from this[1] article on Linux journal and Luke Smith's YouTube playlist[2] on groff.
To practice, I'm trying to re-typeset a paper I wrote in school that follows the Chicago Manual of Style[3]. I formatted the original in MS Word using a template my school provided, so I have something to visually compare against. I'm using the -ms macro set, mostly because that's what Luke Smith demos in his videos so that's what I got started with.
I've already got a reasonable imitation of the original document, which is fun and a bit rewarding. But there's a couple of very small details that I'm finding difficult to crack. Are you very well-versed with -ms? In particular, right now I'm trying to figure out how to add one blank line of space in footnotes AFTER the horizontal line, but BEFORE the first footnote begins. I suspect I'll need to redefine the -ms macro that controls the trap for footnotes...? But I haven't figured out which macro that is just yet.
[0] "The GNU Troff Manual", https://www.gnu.org/software/groff/manual/groff.html
[1] "Typesetting with groff Macros", https://www.linuxjournal.com/article/4375
[2] "groff/troff for Minimalist Document Complication", https://www.youtube.com/playlist?list=PL-p5XmQHB_JRe2YeaMjPT...
[3] "The Chicago Manual of Style Online", https://www.chicagomanualofstyle.org/home.html
First I would point you to the manpage, but, we all know that manpages are a mess, so it might not be there. I will however point you, perhaps not /super/ helpful, but alas, I know not of any better solution. If you go to /usr/share/groff/current/tmac/s.tmac and search for «module fn», that should be the code for the footnotes. Aside, the -ms name comes from this, -m means macro, and whatever letter comes after it is the macro set, hence why -man will be called an.tmac in groff source code, or in this case, s.tmac.
I am not sure where documentation is on traps in groff, but I assume it’s buried withing some manpage or info document somewhere. Software is crap, eh? :D
Of course, you could ask in the groff mailing list[1], they are usually pretty helpful in these matters. Which course of action you chose is of course up to you, I will investigate for myself as well to educate myself more on traps.
[1]: mailto:groff@gnu.org
He can try "Tectonic" [0] - a modern XeTeX based TeX/LaTeX distribution that installs a minimum system and then downloads and installs dependencies on-demand. Tectonic is written in C and Rust [1].
[1] https://github.com/tectonic-typesetting/tectonic/issues/459
I remember installing teTeX (the predecessor of TeX Live) back in 2003 and I despaired at the file size because I knew it would take days to download on the shitty dialup connection I had at the time. Yeah, it wasn't 5 GB big back then, but it was certainly big by 2003 standards.
I'm struggling to understand this sentence. Who are they? What's a boonie? What's not finished?
My answer to "how long do I want my career to be?" will never be "until my body or mind fail me".
Now, Brian obviously has much better instincts about performance than I do and may even have tried some things and benchmarked them, but my guess would have been that you should stay in UTF-8 because it's always faster for the typical cases.
I think these days people don't bother with UTF-32 too much because it's not even like you have a clean "one 32bit int, one character" relation anyway since some characters can be built from multiple codepoints. Since generally most code manipulating character strings are interested in characters and not codepoints, UTF-32 is effectively a variable-length encoding too...
90% Only care about ASCII, thus individual bytes in UTF-8, and so UTF-32 just wastes memory
1% Care about individual code points, but spread over multiple bytes (e.g. the double dagger ‡), UTF-32 is perfect
9% Care about multiple code points (to form e.g. a Flag, or é written in combining form, or two women kissing) and so UTF-32 doesn't really help again
But probably not.
Edit: Mixed up code units and code points.
Can you provide some examples? People say this a lot, but the cases I've been able to find tend to be things like U+01F1 LATIN CAPITAL LETTER DZ, which is only not well defined in the sense that Unicode defines it wrong (as one character rather than two) presumably-on-purpose, for compatibility with one or more older character encodings.
Also, things like æ and œ are much easier to deal with if they are a single glyphs. Their upper-case versions are respectively Æ and Œ even in languages where they are two letters. I suppose that now we would do it with something like ZWJs to make sure that both letters are transformed consistently but there are technical reasons behind the current situation.
[edit] here you go: dz is the 7th letter of the Hungarian alphabet, but the capital version (in a normal sentence) of dz is Dz and not DZ. Yeah, languages are weird: https://en.m.wikipedia.org/wiki/Hungarian_alphabet
ij is considered two letters in Dutch, although they go by special rules: https://onzetaal.nl/taalloket/ij-plaats-in-alfabet
That's not actually useful, because unicode itself is a variable length encoding.
So it mostly blows up the size of your data.
Though it might have been selected for implementation simplicity and / or backwards compatibility (e.g. same reason why Python did it, then had to invent "flexible string representation" because strings had become way too big to be acceptable).
> A: Unicode is the universal character encoding, maintained by the Unicode Consortium. This encoding standard provides the basis for processing, storage and interchange of text data in any language in all modern software and information technology protocols.
It’s like a catalogue of scripts. We have to extend it when we encounter new scripts that are not catalogued yet (or when we create new emojis)
Converting a byte sequence to a Unicode code point sequence and vice-versa is called transformation format (or more generally an encoding form, but then might not be deterministic) by Unicode (see <https://www.unicode.org/faq/utf_bom.html#gen2>). Unicode specifies UTF-8, -16 and -32. We do not have to change these formats unless the catalogue hit the limits of 32 bits (not a big problem for UTF-8 but for the other two formats). These formats are already able to encode code points that are not assigned yet.
And the confusion now is that a lot of people call what Unicode calls transformation format (i.e. the byte to code point mapping) encoding as well. The term charset is also used sometimes.
PS: Note that a goal of Unicode is to be able to accommodate legacy encoding/charsets by having a broad enough catalogue. This is so that these legacy encoding which may come with their own catalogue can be mapped to the Unicode catalogue. So we have control codes (even though not part of any “proper” human script), precomposed letters (there is a code point for à although it could be represented by a + combining `), things like the Greek terminal form of sigma separately encoded, although that could be done in font-rendering (like generally done for Arabic), and a lot more to aid with mapping and roundtrips.
Edit: by which I mean that I’ve only seen the non terminal form so far in maths but it’s hard to write an algorithm that distinguishes between a word ending in sigma and some juxtaposition of Greek variables.
1. Map a character to a unique number in a character set (in Unicode: called codepoint)
2. Map a number that represents a character in a character set to a bit pattern for storage (transiently or persistently, internally or externally). Unicode code points can be bit-encoded in various ways: UTF8, UCS2 and UCS4/UTF32.
The original code points permit the same character to be represented in various ways, which makes equality checks non-trivial: for instance a character like "ä" can be represented as a single character or alternatively as a composition of "a" + umlaut accent (2 characters).
So far, this is all about plain text, so we are not talking about font families or character properties (bold, italics, underlined) or orientation (super-script, sup-script).
Ken Lunde's opus magnum is the standard book on representing text in various languages other than English, with a focus on Asian languages: https://www.oreilly.com/library/view/cjkv-information-proces...
However you'd probably like to store something more compact than, say, JSON arrays of integers. So there are also a bunch of encodings which turn the integers into bytes. These encodings would work for any integers, but they make most sense to encode Unicode's code points. UTF-8 turns each code point into 1-4 bytes, a pair of UTF-16 encodings turns them into one or two "code units" each of 2 bytes either little or big endian. And UTF-32 just encodes them as native 32-bit integers but again either little or big endian.
[1] At least when talking about code points, which is what matters for regular expressions (unless you want stuff like \X with is not universally supported).
The standard '.' (match any character) in a regexp matches an Unicode code point, not a grapheme cluster. To match a grapheme cluster, you have to use "\X", which is not universally supported.
For example, in Python 3, the builtin module module "re" doesn't support "\X", you have to install the "regex" module for it:
# text is 'e' followed by U+0301 (combining acute accent):
text = b'e\xcc\x81'.decode('utf8')
print(f'text: "{text}"')
import re
print(re.match('^(.)(.)$', text).groups()) # prints "('e', '´')"
import regex # must be installed
print(regex.match('^(\X)$', text).groups()) # prints "('é',)"You have the words "supported" and "implemented" mixed up. Kernighan claims Unicode support, so he is required by the standard the implement \X.
If a software does not implement \X, then it is not compliant, and it would be very wrong to say it supports Unicode. Does anyone have a deeplink showing the evidence for awk?
Which standard is that?
If you're talking about Unicode, the "standard" for regular expressions[1] is an "Unicode Technical Standard", which according to itself isn't required for Unicode conformance:
> A Unicode Technical Standard (UTS) is an independent specification. Conformance to the Unicode Standard does not imply conformance to any UTS.
So awk can claim Unicode support without supporting "\X" (like many regex engines).
If you're talking about POSIX, its regex chapter[2] doesn't mention "\X". In any case I don't think awk claims to conform to POSIX.
[1] https://unicode.org/reports/tr18/
[2] https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1...
For example, I regularly say that Rust's regex crate has Unicode support. But it does not support \X. It's more precisely documented here: https://github.com/rust-lang/regex/blob/master/UNICODE.md
I think I once created one that was about a kilobyte. Is there an upper limit?
I created it using this page https://glitchtextgenerator.com/
The 73 byte X:
x̧̡̬̘͓̖̲̻̻̲̠̪̻͓͙̜̂̓̊̔̀̀͗̑̀̅̀̂̚͘̕̚͘͢͜͠
Unicode in UTF-8 will have variable char length. Plain ASCII will be one byte for each char, but others might have up to 4 bytes. Anything dealing with it will have to be aware of leading bytes.
UTF-32 in other hand will encode all chars, even plain ASCII ones, using 4 bytes.
Take the "length of a string" function, for example. Porting that from ASCII to UTF-32 is just dividing the length in bytes by 4. For UTF-8, you'd have to iterate over each character and figure out if there is a combination of bytes that collapse into a single character.
You have to do that with UTF-32 as well. Yes, every codepoint is 32 bits, but every character can be made up of one or more codepoints.
U+004D in UTF-8 is 4D, in UTF-32 is 0000004D
U+0430 in UTF-8 is D0 B0, in UTF-32 is 00000430
I took this examples from page 102 of The Unicode Standard Version 5.0.
These leading zeros on the UTF-32 are what is omitted from UTF-8. One of the encodings is optimized for space, the other for processing speed.
I am no expert on unicode though, there might be something I'm missing (ligatures, this kind of stuff). I would gladly accept a more in depth expalanation on why I am wrong on this.
* As the single code point U+00E0, which encodes 'à'.
* Or as the sequence of two code points U+0061 U+0300, which respectively encode the Latin letter 'a' and the combining acute accent (it's hard to display as a standalone character, so go e.g. here: https://www.compart.com/fr/unicode/U+0300). These two code points get combined into a single grapheme cluster, the technical name for what most people consider to be a character, that displays as 'à'.
As you can see, there is no difference in the visual representation of à and à. But if you inspect the string (in python or whatever) then you'll see that one of them has one code point (one "char"), while the second has two. If you're on Windows, an easy way is to type it into pwsh:
PS> 'à'.EnumerateRunes() | % { "U+{0:X4}" -f $_.Value }
U+0061
U+0300
PS> 'à'.EnumerateRunes() | % { "U+{0:X4}" -f $_.Value }
U+00E0This representation is incompatible with UTF-8, which marks the octet series Cx, Dx, Ex and Fx as leading bytes. You can see the table here: https://en.wikipedia.org/wiki/UTF-8#Codepage_layout
What I believe Kernighan _wants_, is to reuse a lot of code that was designed for ASCII. Code that treats 1 char as 1 byte. In order to do that, he is going to encode each unicode character using 4 of whatever type he was previously using before, zeroing the "pad" bytes, which is exactly what UTF-32 does. This way, he doesn't have to fundamentally change all the types he is already working with. (ps: I looked at the commit after I wrote this, he doesn't seem to be doing what I suggested).
Your PS snippet failed for me "Method invocation failed because [System.String] does not contain a method named 'EnumerateRunes'."
Dit it in bash, which supports UTF-8 and lets you explicitly set the encoding:
$ LC_ALL=C bash -c 'x=à; echo ${#x}'
2
$ LC_ALL=en_US.UTF-8 bash -c 'x=à; echo ${#x}'
1
If I had UTF-32 locales in my machine, "à" would appear as 4. Unfortunatelly I don't know any system that implements UTF-32 to display its behavior.
Let's now reconstruct "à" in UTF-8, telling bash to use only ASCII:
$ LC_ALL=C bash -c 'printf %b \\xC3\\xA0'
à
It's not, but I wrote "Unicode" and "code point", not "UTF-8" and "code unit". It sounds like you don't know the difference, which makes this whole discussion a bit silly and probably a bit pointless. One of the best explanations I've read is this one: https://docs.microsoft.com/en-us/dotnet/standard/base-types/... and especially the section on grapheme clusters.
> Your PS snippet failed for me "Method invocation failed because [System.String] does not contain a method named 'EnumerateRunes'."
Sounds like you're using the outdated windows powershell, not pwsh.
You are talking about another level of abstraction. These UTF-16 builtins are first-class citizens in .NET, and you never have to deal with the raw structure behind all of it unless you want to. C does not have these primitives, a string there is composed of smokes and mirrors using byte arrays.
In summary, you are talking about using a complete, black box Unicode implementation. I'm talking about the tradeoffs one might encounter when crafting stuff that goes inside one of these black boxes, and it's different from the black box you know.
> Yes, every codepoint is 32 bits, but every character can be made up of one or more codepoints.
And you expressed surprise and incredulity at the idea. I explained that a "character" (which, given the context, is to be taken as a "grapheme") can, indeed, take up more than one code point. This has nothing to do with UTF-32, UTF-8, or .NET's implementation. It's inherent to how Unicode works.
As an even more obvious example, try to figure out how many bytes are in the character ȃ encoded as UTF-32, using whatever method you'd like. (I say "more obvious" because you'll be forced to copy-paste the character I've used in your code editor.) Other examples include emojis such as this one: https://emojipedia.org/woman-golfing/ (that I can't use in the comment box for some reason).
Then for some reason you felt compelled to offer a rebuttal that showed you didn't understand the difference between a grapheme and a code point. So I just linked some doc. I'm not attacking you.
"ȃ" uses two bytes in UTF-8, 2 bytes in UTF-16 and 4 bytes in UTF-32. The woman golfing uses 4 bytes in UTF-8, UTF-16 and UTF-32.
My surprise was at the idea of having to look up a variable length sequence of bytes in a string stored as UTF-32. To me, UTF-32 exists exactly for the use case of "I don't want to calculate variable length" (optimizing for speed), and UTF-8 exists for "I don't want to use more bytes than I need" (optimizing for space).
I never used the term "codepoint" in this entire thread until now. I was originally talking about storing bytes, hence my little discomfort of not being able to communicate what I'm trying to say. Not feeling attacked, just incapable of expressing, which might have come off wrong. Sorry about that.
BTW, there are many things that I don't understand about Unicode. I never read the full standard. I don't know enough about a grapheme to tell whether it is something that impacts or not the number of bytes when storing in UTF-32.
Why we are talking about UTF-8 versus UTF-32 and not Unicode as a whole? Because there is a code comment about these two in the commit linked by the OP, which sparked this particular subthread.
No. It's made up of 5 code points. Each of these takes 32 bits, or 4 bytes, in UTF32. So that emoji, which is a single grapheme, uses 20 bytes in UTF32. Once again, just try it yourself, encode a string containing that single emoji in UTF32 using your favorite programming language and count the bytes!
https://www.unicode.org/faq/utf_bom.html
> Q: Should I use UTF-32 (or UCS-4) for storing Unicode strings in memory? > > This depends. It may seem compelling to use UTF-32 as your internal string format because it uses one code unit per code point. (...)
It also confirms what I said about implementation vs interface (or storage vs access, whatever):
> Q: How about using UTF-32 interfaces in my APIs? > > Except in some environments that store text as UTF-32 in memory, most Unicode APIs are using UTF-16. (...) While a UTF-32 representation does make the programming model somewhat simpler, the increased average storage size has real drawbacks, making a complete transition to UTF-32 less compelling
Finally:
> Q: What is UTF-32? > > Any Unicode character can be represented as a single 32-bit unit in UTF-32. This single 4 code unit corresponds to the Unicode scalar value, which is the abstract number associated with a Unicode character.
So, it does in fact reduce the complexity of implementing it _for storage_, as I suspected. And there is a tradeoff, as I mentioned. And the Unicode documentation explicitly separates the interface from the storage side of things.
That's good enough for me. I mentioned before there might be some edge cases like ligatures, and you came up with a zero-width joiner example. None of this changes these fundamental properties of UTF-32 though.
Now to try one last time, you are misreading the spec and not understanding important concepts. Take the “woman golfing” emoji as an example. That emoji is not a Unicode “character” and is part of why it can’t be represented by a single UTF32. That emoji is a grapheme which combines multiple “characters” together with a zero width joiner, “person golfing” and “female” in this case. Rather than have a single “character” for every supported representation of gender and skin color, modern emoji use ZWJ sequences instead, which means yes, something you incorrectly think is a “character” can in fact take up more than 4 bytes in UTF32.
I said I might be wrong _multiple times_, and its genuine. I'm glad you appeared with an in-depth explanation that proves me wrong. I asked exactly for that.
The first examples in this thread are not zero-width-joiners (á, â) or complex graphemes. They all could be stored in 4 bytes. It took some time to come up with the woman golfing example.
By the way, one can still implement reading "character" by "character" in sequences of 4 UTF-32 bytes, and decide to abstract the grapheme units on top of that. It still saves a lot of leading byte checks.
Maybe someone else learned a little bit reading through the whole thing as well. If you are afraid I'm framing the subject with the wrong facts, this is me assuming, once again, that I never claimed to be a Unicode expert. I don't regret a single thing, I love being actually proven wrong.
I encourage you to reread the comment I replied to again and see if it has the tone of someone “trying to learn” or rather something different.
> I don't regret a single thing, I love being actually proven wrong.
Me too!
To me it sounds ok. I'm not an english native speaker though, so there is a handicap on my side on tone, vocabulary and phrasing.
My intent was to admit I had wrong assumptions. At some point before this whole thread, I _really_ believed all graphemes (which, in my mind, were "character combinations") could be stored in just 4 bytes. I was aware of combining characters, I just assumed all of them could fit in 32bit. You folks taught me that it can't.
However, there's another subject we're dealing with here as well. Storing these characters at a lower level, whether they form graphemes or not at a higher level of abstraction.
The fact that I was wrong about graphemes, directly impacts the _example_ that I gave about the length of a string, but not the _fundamental principle_ of UTF-32 I was trying to convey (that you don't need to count lead bytes at the character level). Can we agree on that? If we can't, I need a more in-depth explanation on _why_ regarding this as well, and if given, that would mean I am wrong once again, and if that happens, I am fine, but it hasn't yet.
As I said in the other thread, to try to minimize confusion, consider Character and Grapheme as synonymous. They are made up of one or more codepoints. The world you’ve made up that everything is characters and they all take exactly four bytes in UTF32 is just wrong. Yes, many graphemes are a single codepoint, so yes, they are 4 bytes in UTF32, but not ALL (and it’s not just emoji’s to blame).
If what you’re on about is the leading zeros, yes, they don’t matter individually. Unicode by rule is limited to 21bits to represent all codepoints so the 11 bits left as leading zeros are wasted, which is why folks don’t use UTF32 typically as it’s the least efficient storage wise and doesn’t have really any advantage over UTF-16 outside easy counting of codepoints (but again, codepoints aren’t characters).
I'm constantly pointing you _to the awk codebase_. It's a relevant context, the title of the post and it matters. Can you please stop ignoring this? There's no Unicode library there, it's an implementation from scratch.
If you are doing it from scratch, there's a part of the code that will deal with raw bytes, way before they are recognized as Unicode things (whatever they might be).
Ever since this entire post was created, the main context was always this: an implementation from scratch, in an environment that does not have unicode primitives as a first-class citizens. Your string functions don't have \u escapes, YOU are doing the string functions that support \u.
https://github.com/onetrueawk/awk/commit/d322b2b5fc16484affb...
I am talking about that environment. You are not.
UTF16 (12 bytes total):
\ud83c\udfcc\ufe0f\u200d\u2640\ufe0f
UTF32 (20 bytes total):
u+0001f3ccu+0000fe0fu+0000200du+00002640u+0000fe0f
UTF8 (16 bytes total):
\xf0\x9f\x8f\x8c\xef\xb8\x8f\xe2\x80\x8d\xe2\x99\x80\xef\xb8\x8f
If you had all of these expressed as pure hexadecimals (or octals, or any single-byte unit), how would they be serialized?
Then, once all of them are just hexadecimals, how would you go about parsing one of these sequences of hexadecimals into _characters_? (each hexa representing a raw byte, just like in the awk codebase we are talking about)
Another question: do you need first to parse the raw bytes into characters before recognizing graphemes, or can you do it all at once for both variable-length and fixed-length encodings?
That’s the actual encoding for that grapheme as specified by the spec for UTF8, UTF16, and UTF32.
> \u and u+ are in a higher level of abstraction.
No, it’s not, it’s how you write escaped 16bit and 32bit hexadecimal strings for UTF-16 and UTF-32 respectively. Notice there’s 4 hex characters after \u and 8 hex after u+. Those are the “raw bytes” in hex.
> The only raw bytes I am seeing here are in the UTF-8 string, which you decided to serialize as hexadecimals
All three forms are “raw bytes” in hex form. \x is how you represent an escaped 8 bit UTF-8 byte in hex.
> Another question: do you need first to parse the raw bytes into characters before recognizing graphemes, or can you do it all at once for both variable-length and fixed-length encodings?
You need to “parse” (more like read for UTF16 and UTF32, as there’s not much actual parsing outside byte order handling) the raw bytes into codepoints. To try to minimize confusion, consider Character and Grapheme as synonymous. They are made up of one or more codepoints. It really doesn’t matter if it’s variable length or fixed length, you still have to get the codepoints before you can determine character/graphemes.
You're absolutely right about what is a character and what is a grapheme. I already said that, this subject is done. You're right, no need to come back to it. You win, I already yielded several comments ago.
Now, to the other subject: I would very much prefer if we talked only about bytes. Yes, talking only about bytes makes things harder. Somewhere down the line, there must be an implementation that deals with the byte sequence. I'm talking about these, just above the assembler (for awk). There IS confusion at this level, no way to avoid it except abstracting it by yourself, byte by byte (or, 4 bytes by 4 bytes in UTF-32).
"â" uses two bytes when encoded in UTF-8, while "ȃ" (which was what bzxcvbn supplied as an example and you pasted in the quoted section) uses three bytes when encoded in UTF-8.
>>> s="ȃ"
>>> len(s)
2
>>> s.encode('utf8')
b'a\xcc\x91'
>>> import unicodedata as ud
>>> [ud.name(c) for c in s]
['LATIN SMALL LETTER A', 'COMBINING INVERTED BREVE']Why else might you need to know the length? If it's to know how much space to allocate in a GUI (or even on a console) then neither encoding is going to help.
Maybe it's because of some arbitrary limitation like "your name must be less than 50 characters" and I'll just say that if that's the case, you are doing it wrong (if you need to limit it for storage/efficiency purposes, fine, but you will probably be better off limiting by bytes and using UTF-8 since most people will be able to squeeze in more of their names).
I'm not saying there aren't reasons for needing to know the "length" (number of Code Points) of a string, and certainly many existing algorithms are written in a way that they assume that calculating string length and being able index arbitrarily into the middle of a string are fast (O( 1 ) for indexing) but in reality, for almost any real world problem beyond "how much storage do I need" almost everything you need to do actually requires iterating over a string one Code Point at a time (which is O( n ) for both, with the biggest difference being that UTF-8 may require more branching, but also it's common enough that in many cases between vectorization and just generally better optimizations because of it's popularity, UTF-8 will do just fine while usually using less storage, which can significantly benefit CPU cache locality).
In fact, the return value of the u8_rune as implemented in the branch we are discussing (https://github.com/onetrueawk/awk/compare/unicode-support) returns a length to be used as an offset later.
This is not me saying, it's the author. There is a code comment there:
> For most of Awk, utf-8 strings just "work", since they look like null-terminated sequences of 8-bit bytes. Functions like length(), index(), and substr() have to operate in units of utf-8 characters. The u8_* functions in run.c handle this.
I know there might be different ways of doing it, but we're talking about a specific implementation.
I was wrong to assume he is storing stuff in UTF-32. He could have, but there was already code in place there to make the UTF-8 storage easier to implement.
A complete guess on my part though, I never looked into AWK's source code.
Similar with substr() and other string functions, which when operating as bytes are O(1), but become O(N) when trying to count the number of codepoints as UTF-8.
GNU Gawk has a fancier approach, which stores strings as UTF-8 as long as it can, but converts to UTF-32 if it needs to (eg: the string is non-ASCII and you call substr).
It looks like Brian Kernighan's code has the same issue with length() and substr(). I'm going to try to email him about this, as I think it's kind of a performance blocker.
The most challenging part, he said, was updating the regex engine, which "was written by Al Aho in 1977 and hasn't really been touched much since".
It is surely better than dealing with UTF-16 "surrogate pairs"[2] in most pre-UTF-8 tech where a `char` is 16-bits but can't fit all Unicode codepoints without another 16-bit `char`.
[1]: https://doc.rust-lang.org/std/primitive.char.html#representa...
But as an internal representation, some of it can be ignored by choice.
$ echo 'ö' | awk '{print length}' $ awk -V
awk version 20211208
# awk -version
awk version 20210215 $ awk -version
awk version 20200816I’ve always found git to be exceedingly simple in design. Though, the CLI is a quite messy I grant you.
Whether it’s git or vi/emacs or C or LaTex or whatever, there are a bunch of us old-timers who went through the pain already and now notice the modest loss of capability on hg or VSCode or whatever.
But even as such an old-timer, I don’t think it’s a good idea to default everyone into this low-level shit. Mercurial and VSCode and Python are fine, you can do great work without “the bare metal”.
Edit: Clarified that it’s a “revision control” power-user tool, plenty of “power users” have more typical revision-control needs.
I have only worked with one person really who knew is backwards and forwards. That seemed helpful at first until he used his deep knowledge to try some sort of tricky fix-up and in the process lost some of my work. Given that a version control system's one job is to not lose work, I was very disappointed.
Not confined to your local machine?
He was very apologetic about it, and it wasn't more than a day or two of work, so I was ok with it. But it was one of many experiences that have left me permanently suspicious of doing anything fancy with git. Which is fine, because for a lot of reasons mostly not to do with any particular VCS, I work to keep branching to an absolute minimum.
When I took my undergrad roughly a decade ago, github was already a thing but our courses were still using subversion.
Academia is slow to adopt new tools.
I haven't used it, but my understanding was all the unix tools were upgraded to work with unicode - don't quite see why it's taken so long if the work was done already years ago
I've always found that for my personal use cases, writing a little Python snippet has always been much faster and simpler than understanding what CLI tool to use, and how to use it, to achieve the same thing.
I've had to work on environments where awk was available by default, but Python was not (and was not going to be).
It can be good to have a screwdriver for every type of screw in the toolbox.
https://github.com/onetrueawk/awk/compare/master...unicode-s...
Long live, K!
Following the spirit of UNIX, I did a little analysis on the upvotes this post got over time (fish-shell):
while true; curl -sL 'https://news.ycombinator.com/item?id=32534173' | pup '#score_32534173 text{}' | awk -F'[^0-9]*' '{print $1}' | tee -a points; sleep 15s; end
I started it approx. when I posted it. Now ~2 hours have passed since. Using `gnuplot`:
f(x) = a*x+b; fit f(x) "points" via a,b; set terminal png size 1920,1080 enhanced font "Inconsolata,20" ;set output "HN-analysis.png" ;set grid; set ylabel "points";set key bottom right ; set xlabel "sample # (15s interval)"; plot 'points' w linesp lt 7 lw 3 lc rgb "orange", f(x) lc rgb 'blue' lw 2
(The jump #100 sample is due to a network error on my side)
And here are the coeffs. of a linear fit over the data (note that every 4 samples is 1 minute, so this post got ~1.52 upvotes per minute)
a = 0.380809, b = 19.8437( For bonus fun, fit successive unbiased moving averages of a selectable width, for further fun do this for non uniform sample times .. time weighted, and look beyond simple moving averages to (say) Savitzky–Golay filter family for both uniform and non uniform sampling intervals )
Are you suggesting another method for graphing?
gnuplot was/is Berkley / GNU developed software.
Guess more of a 70's/80's pre-open source observational comment.
Even Kernighan struggles with git.
Pull requests are feature of GitHub, not a part of git.
https://docs.github.com/en/pull-requests/collaborating-with-...
Git has tooling to help with those, so it kinda is a git feature: git request-pull. https://git-scm.com/docs/git-request-pull
I guess it might be more accurate for me to think about pull requests as Github's reification of the social protocol of pulling among kernel developers.
Figuring out how all of this works is substantially more difficult I find in practice than fixing many longstanding trivial bugs in a great deal of software.
Some good reasons not to use GitHub is because you’re familiar with standard/traditional tools, or because you prefer not to use centralized services. Both of those are fine reasons! But “the traditional way is easier” isn’t.
They just said, "The culture around p.r.s is truly a high barrier of entry for many people." That's true and it's important to acknowledge that on any project that wants contributions from as many people as possible. When I was at Code for America I saw smart people putting plenty of time into helping people get over that barrier.
That's certainly the case here. If a professor of CS receives help from an open-source maintainer who's been coding for decades and still doesn't feel confident, then it's safe to say a) there's room for improvement, and b) until we figure out what the improvement is, we should make sure that we're providing the necessary support to everybody we want to contribute.
The fact that (for example) GitHub requires a fork for you to send a PR to a project (that you don’t have push access to) is soooo overkill.
And since Git has a builtin mechanism for tracking such things, called branches, we could ask users to create a new one. Then add a possibility for people to comment on the proposed change. Sounds like you're incrementally reinventing PRs.
We're talking about usability here, of course the fundamental features are available in Git. It's Git!
Here [0] is a more well written out version of this idea (by a developer of Mercurial).
[0] https://gregoryszorc.com/blog/2020/01/07/problems-with-pull-...
In many cases, it is sufficient to simply send an email with:
> There's a bug in the function `handle_request` in `src/network/core.rs` that can cause it to return a double answer when invoked during a leap second. This fixes that issue: ...
And just include the new function inside of the email body, without attachment.
That should be sufficient for many cases, but many projects do not allow this and demand p.r.s.