Cicada – Unix shell written in Rust(github.com) |
Cicada – Unix shell written in Rust(github.com) |
While Cicada is pretty clearly modeled on the "old" generation of shells (sh, Bash, Zsh, etc.), one has to wonder what a more modern shell might look to address some of the problems of its predecessors like pipes that are essentially text-only, poor composability (see `cut` or `xargs`), and terribly obscure syntax.
PowerShell seems to have been a flop outside of the Windows ecosystem, and between overly elaborate syntax and COM baggage, was probably rightfully passed over, but it probably had the right idea. Imagine a future where we're piping structured objects between programs, scripting in a modern language, and have IntelliSense quality auto-completion for every command.
---
Text is compatible with all systems, past and present, and can be used to model more complex objects. Let's not add features to the core on a "why not" please.
So in principle, treating those as complex object structures is the right way to go. Also, I believe this is the idea behind D-Bus and similar modern Unix developments.
However, what's hard is to provide good tooling with a simple syntax that is simple to understand:
* Windows Registry and Power Shell show how not to do it.
* The XML toolchain demonstrate that any unnecessary complexity in the meta-structure will haunt you through every bit of the toolchain (querying, validation/schema, etc.).
* "jq" goes somewhat into the right direction for JSON files, but still hasn't found wide adoption.
This appears to be a really hard design issue. Also, while deep hierarchies are easier to process by scripts, a human overview is mostly achieved by advances searching and tags rather than hierarchies.
A shell needs to accomodate for both, but maybe we really just need better command line tools for simple hierarchial processing of arbitrary text file formats (ad-hoc configs, CSV, INI, JSON, YAML, XML, etc.).
The sole point of structural data is to turn the storage into a formal system, and enable more math operations on the entries, which align to the desired semantics. Python/js/clojure scripts extract some structural aspects from text, and then the story becomes the same as structural data processing.
For modern shell, please check out xonsh: http://xon.sh/ - powered by Python - It's super cool!
Pipes work fine with binary data, you just need to be piping to a tool that works with binary data rather than text e.g.
cat <somebinaryfile> | openssl base64
openssl base64 <somebinaryfile
On the plus side, you do get a prize for suggesting it [1]
Something involving bulk binary data moving over a pipe which isn't an indirect redirection would be:
gzip somefile | ssh user@host "gunzip >somefile"
Although, again, there's a perfectly good -c flag to SSH that would do the same thing.
Probably the most common example of tool-to-tool binary communication over pipes is:
find -print0 | xargs -0
You'd either have to be very careful (e.g. feature flags guarding every change) or expect a surprising amount of things to fail.
It seems like the way to go to use non-POSIX shell as the default shell without changing login shell, is to have .bashrc `exec`'d that shell when it is running in interactive mode. Regardless, I would really love to see bash-like shell that provides out of the box experience in the same level as fish.
A new system and set of utilities. None of the Unix environment works in that world, and shoehorning it in would feel incredibly clunky.
The problem with passing objects around though is it can cause issues with the parallel nature of pipes. ie the programs in a chain of pipes can run concurrently since the data is being passed is just a stream. But with objects you need to read the object in its entirety to ensure it is a valid object. This means each process is waiting for the previous process to finish outputting it's object before the next can start processing it. While this is less of an issue with smaller chunks of data in a chain, it would become really noticeable really quickly as your data scales up.
I'm sure will be workarounds for the above problem but my project is still young so there are other bugs I'm more focused on (for me I'm more interested in getting an IDE-level auto-complete implemented so writing one liners in the Shell is as natural as writing your favourite language in your preferred development tool.
[1] https://github.com/playframework/play-iteratees [2] http://www.reactive-streams.org/
-rw-r--r-- 1 brandur staff 6.5K Mar 25 15:37 Makefile
-rw-r--r-- 1 brandur staff 63B Jul 10 2016 Procfile
-rw-r--r-- 1 brandur staff 1.6K Mar 11 07:20 README.md
drwxr-xr-x 4 brandur staff 136B Oct 16 2016 assets/
drwxr-xr-x 4 brandur staff 136B Jul 15 2016 atom/
drwxr-xr-x 4 brandur staff 136B Apr 26 2016 cmd/
What if I could do something like `ls -lh | select 6` (select the 6th column of data):
Mar 25 15:37
Jul 10 2016
Mar 11 07:20
Oct 16 2016
Jul 15 2016
Apr 26 2016
Now say I want to sort these dates and pick the earliest. Once again, shells make this extremely difficult. Because the dates are not lexigraphically orderable, I'd have to use some fancy parsing, or try to step back to `ls` and have it somehow order by date.
Imagine if I could instead to something like `ls -lh | select 6 | sort | first`:
Apr 26 2016
The part that the shell would have to provide (as opposed to the programs) is a "smart pipe" that understands more than just a basic text stream. It would also have to know when there is no pipe connected, and print as pretty strings when it knows the output is going to `STDOUT`.
http://users.eecs.northwestern.edu/~jesse/pubs/caml-shcaml/
PowerShell definitely made a lot of mistakes they should have known needed fixing. Like the need for signed scripts.
May not be quite the same as what you mean, but check out osh (a Python tool, a sort of shell, for doing distributed command-line and scripting operations on clusters of nodes). I had blogged about osh briefly here:
Some ways of doing UNIX-style pipes in Python:
https://jugad2.blogspot.in/2011/09/some-ways-of-doing-unix-s...
Interestingly, later on, when I blogged this:
Akiban, new database, supported by SQLAlchemy:
https://jugad2.blogspot.in/2012/10/akiban-new-database-suppo...
the creator of osh, Jack Orenstein, who was then at Akiban (the company behind the Akiban product), commented on that post, giving more details about both osh and what it was used for at Archivas, later acquired by Hitachi Data Systems, and also said something about Akiban. And now I just saw by googling that it (Akiban) was acquired by FoundationDB.
All of that said... nothing is stopping you from piping binary objects between tools in Unix shells. In fact, it works great, and I'm curious what functionality you are looking for that doesn't exist. The standard tools like cut and grep don't work great with binary data, but they aren't meant to. There are format-specific tools aplenty, and stuff like bbe exist for generic work. And for structured text, tools like `jq` are phenomenal.
Indeed, PowerShell is onto something. Such delight it is to work with. Especially when you start to build your own tools for it.
I'm hoping Powershell on Linux will soon be at par with the Windows counterpart (right now it's pretty buggy)
However, you should check out fish; it improves on bash/zsh/whatever syntax in sane ways.
Near the end, he starts talking about terminals and making a new terminal standard (~ 17:30 mins in).
Got me wondering what would happen if we embedded modified form of HTTP response headers into the beginning of every UNIX command line stream. Let's tag this version `HTTP/UNIX.1`. This is to differentiate that this HTTP isn't due to a request, but as part of a standard 'UNIX' command response. Otherwise programs could follow RFC2616 section for HTTP response formats [1].
Speaking to the existing ecosystem of tooling, it'd be straightforward (trivial?) to add native support into existing shells to support this. For example now when you run `ls` your shell settings would be `SHELL_DISPLAY_HTTP_UNIX_PRETTY="terminal/text:terminal/json"`. Programs without native support built in could be handled by adding a "http_strip" program. Otherwise adding support into command line programs would be simple as libraries to handle HTTP/1.1 exist in most any language/platform and only a the "Response" header section would be needed of those. Alternately a generic wrapper could created to handle the http response info.
Examples:
HTTP/UNIX.1 200 OK
Date: Mon, 27 Jul 2009 12:28:53 GMT
Server: ifconfig lo0
Content-Length: 248
Content-Type: terminal/text
Connection: Closed
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
options=1203<RXCSUM,TXCSUM,TXSTATUS,SW_TIMESTAMP>
inet 127.0.0.1 netmask 0xff000000
inet6 ::1 prefixlen 128
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1
nd6 options=201<PERFORMNUD,DAD>
HTTP/UNIX.1 200 OK
Date: Mon, 27 Jul 2009 12:28:53 GMT
Server: sysinfo
Content-Length: 107
Content-Type: terminal/json
Connection: Closed
{
"aggr0": {
"LACP mode": "active",
"Interfaces": [
"e1000g1",
"e1000g0"
]
}
}
1: https://www.w3.org/Protocols/rfc2616/rfc2616-sec6.html
edit: formatting whitespace?
corehttp ls -l ...https://github.com/redox-os/ion
It's intially build with RedoxOS (in Rust as well) underneath, but now also runs on Linux. Seems to be a bit more mature.
I wonder what sets these two projects apart, and/or if the devs of Casada know of Ion's existence.
What they have in common though… is that job control (Ctrl+Z) is not implemented yet :(
Something that's been capturing my imagination recently is sshing into a machine, pushing an appropriate shell binary to /tmp, and then executing it. If you have an exotic preference for shell (or vim config, or whatever), we've presumably generally got sufficient bandwidth these days to do a virtually instant user-space install and execution, no?
Just expect a few questions from the admins when you do this.
#!/bin/bash -x
HOST=$1
scp -o ControlMaster=auto -o ControlPersist=30 ~/.vimrc $HOST:~/.vimrc
ssh -o ControlMaster=auto -o ControlPersist=30 $HOST
†: the specific use-case was for development of multi-machine GUI applications that run in configurations like "display walls" or "immersion rooms". for every developer to have their own "display wall" or "immersion room" would cost lots of $$$, so many of the design decisions were based around the needs of a team of N developers that "shares" these systems.
I think people are going to ask "Why?" and "What's the difference between this and bash?" Might want to cover that in your README.
I don't think this is anything more than a toy to play with rust.
To fix all those things you wouldn't end up with a traditional Unix shell, which I think would be a great project, but there are clearly two mutually exclusive projects to do:
1. A Unix-like shell (this)
2. A robust shell suitable for writing scripts
/cry
Why?
$ echo $((1 + 2 * 3 - 4))
3 function c() {
echo $(($@))
}
alias c='noglob c'$ echo test 1 + 2>err
Or what if there are files with these names?
$ cp /bin/grep 42
$ 42 + 1
For example, I forced myself to learn screen really well because even though I like tmux and it has some features lacking in screen, I would rather support a tool I know is more aligned with freedom for the user. Same with i3 vs awesome, etc.
An interesting side benefit of this is I have noticed the complexity of my stack has been reduced because of this selectiveness.
In fact, I genuinely don't understand the "freedom for the user" aspect. The only "freedoms" the GPL cares about are freedoms for developers (end users don't care in the slightest about whether they can get the source code, etc), but GPL is far and away the most restrictive license I've ever seen in terms of taking away developer freedoms. So when people say the GPL provides freedom for the user, it makes no sense, because what it's doing is taking away freedoms from anyone who actually cares about source access. In fact, all the GPL really seems to do is protect the "freedom" of the original developer to ensure access to any changes made by other people, at the cost of taking away the freedoms of all of these other people.
1. "the GPL really seems to do is protect the "freedom" of the original developer to ensure access to any changes made by other people" The GPL literally does not do that, the "other people" only have to give the modified sources to people who get the binary from them; they don't have to give the modified sources back to the original developer. As a non-theoretical example, the Grsec guys only give their Linux kernel modifications to their customers, and do not give the modifications back upstream to Linux. It's about making sure that the end user gets access to the code, which I know you said is silly because the users "don't care in the slightest", but...
2. You re-defining user to be someone who doesn't look at the code is silly. Given a piece of software I have absolutely no intention of being a "developer" for, I would still like to receive the source code. I would like to be able to study it to figure out how it works, the same as when I took apart and studied clocks as a kid (an activity that didn't magically transmute me from a "clock user" into a "clock maker"!). When some software on my computer (or the computer of a friend or family member) breaks, I would like to be able to pop open the source and see what's going on, the same as when I pop the hood when something goes wrong with a car--I'm not interacting with that software as a "developer", just as I'm not interacting with the car as a "car maker". Sure, the fact that I am a developer means I'm pretty qualified to know what I'm looking at when I look at the source, just as being an engineer at an auto company would make me pretty qualified to know what I'm looking at when I pop the hood of my car. But fundamentally, the relationship I have with that software/car is that of a user, not that of a developer. And even if I weren't a programmer, I would want to receive the source, so that when it breaks, and I ask my nephew or whoever to look at it, that he can see the source and isn't locked out from helping me out. We don't call farmers "engineers" for fighting for the "right to repair" their own farm equipment; and we shouldn't call computer users "developers" for fighting for the right to repair their own computers.
Man do I hate licensing.
By contrast Android devices all run the Linux Kernel, which is licenced under the GPLv2. Android device makers are obligated to release the kernel code they use, so users or upstream developers could use it. It's a bit more complicated than that, because the code doesnt necessarily have to be able to be loaded on the device (GPLv2 doesn't say anything about locked bootloaders or cryptographic signing, for example, and binary blobs that work in tandem with GPL code are a bit of a grey area, as far as I know).
Parent commenter prefers the latter style, or possibly even GPLv3, which imposes additional restrictions on what you can do. See Tivoization [0].
"He has, however, granted "IBM, its customers, partners, and minions" permission "to use JSLint for evil", a solution which appeared to satisfy IBM's lawyers."
:D
Given IBM's history of making Jew-counting machines for the Germans during WWII, that exception is particularly disturbing.
Also JSON [2].
start
|
V
if I modify it, and give someone a
compiled binary of that, should I also
have to give (or offer) them the source?
| |
yes | | no
| V
| MIT/X11 license
| (alternatively,
| Apache 2.0, or
| 2- or 3-clause BSD)
V
is it a library
or a program?
/ \
library / `----, program
V \
can it be used by programs \
that DON'T give/offer the \
source with binaries? \
| \ \
yes | \ no V
V `-----------> GNU GPL
GNU LGPL (alternatively, GNU AGPL)
As for the "alternatives" in parenthesis at the leaves of the chart: if you don't care about licenses, the default is probably fine, but if someone told you that you should use one of the alternatives at that leaf, I wouldn't argue. (Apache 2.0 comes in over MIT if you care about patents, AGPL comes in over GPL if you care about SaaSS)
Good catch! I actually use another command that generates binary output that I pipe to OpenSSL to convert to base64 but rather than type out the full command I thought 'what's the easiest way to get some binary data on stdout' and 'cat binaryfile' was it.
[1] by definition trivial code isn't copyrightable - but "trivial" is subjective. If you, as the author feel it is, might as well clearly signal that and use cc0.
This is so frustrating. One of Crockford's most persuasive points in his writing and lectures about Javascript is that computer programs are no place for self-expression. When he explains what is wrong with the language, he gives astute suggestions on foolproof ways to workaround the language's weak points by avoiding ambiguity. He's even written JSLint to help the programmer do just that without having to research every idiosyncratic pitfall that would come from just winging it.
Yet here he is-- in a domain for which he has absolutely no expertise-- expressing himself in a licensing clause. Causing measurable hours of waste because Debian or IBM or insert-org-here has no experience with his idiosyncratic license and no easy way to predict what are its effects.
For example:
export MARKPATH=$HOME/.marks
function jump {
cd -P $MARKPATH/$1 2> /dev/null || (echo "No such mark: $1" && marks)
}
function mark {
mkdir -p $MARKPATH; ln -s $(pwd) $MARKPATH/$1
}
function unmark {
rm -i $MARKPATH/$1
}
function marks {
ls -l $MARKPATH | sed 's/ / /g' | cut -d' ' -f9- && echo
}
_jump()
{
local cur=${COMP_WORDS[COMP_CWORD]}
COMPREPLY=( $(compgen -W "$( ls $MARKPATH )" -- $cur) )
}
complete -F _jump jump
Me too. Looking at them, they all start with something like
test $# -eq 2 || return
Speaking of primitiveness, in strict POSIX sh, there's no such thing as local variables in functions!!
The login shell need to source /etc/profile and /etc/profile.d during logins to populate environment variables. Some apps that expect those environment variable to be present wrote to /etc/profile.d with an expectation that a POSIX-compatible shell and will read the directory (by source-ing those files). The environment variable getting set there ranging from PATH, LANG, to application/distro-specific like MOZ_PLUGIN_PATH.
So when you changed the login shell to something that no longer reads /etc/profile.d (like fish, which actually say it's "interactive shell" in the man page) then application that rely on those variables will start to behave in some funny way, which was the point I was trying to make.
No need for that. UTF-8 is a superset of ASCII, and ASCII already includes a handful of control codes that could be used here.
I would probably use Python, Go or Powershell.
http://users.eecs.northwestern.edu/~jesse/pubs/caml-shcaml/
Incidentally, that would also dramatically decreased security and maintainability problems.
I used to be a big fan of permissive licenses until I bought a $700+ android phone a couple of years back and discovered that it did not "support" my native language (it could render the glyphs but system-wide support was not enabled).
Having extensive experience with unicode and how text is usually rendered, I knew exactly how to fix the issue; the fix was likely as simple as injecting an SO that hijacks a specific system library function. However, because the phone was locked down, I was unable to fix the problem myself. All important system apps including SMS and the browser displayed gibberish.
It was the most expensive brick I ever bought. This experience taught me the true value of the GPL and why user freedom far outweighs the freedom of developers
If you can fix it, you're a developer, not a plain old user.
lihaoyi Ammonite$ amm
@ import ammonite.ops._
import ammonite.ops._
@ ls! pwd
res1: LsSeq =
".git" 'LICENSE 'ci 'project 'sshd
".gitignore" 'amm 'integration 'readme 'target
".idea" "appveyor.yml" "internals-docs" "readme.md" 'terminal
".travis.yml" "build.sbt" 'ops 'shell
@ ls! pwd | (_.mtime)
res2: Seq[java.nio.file.attribute.FileTime] = List(
2017-06-21T12:24:41Z,
2017-06-11T13:48:45Z,
2017-06-21T12:29:05Z,
2017-06-11T13:48:45Z,
2017-05-01T03:41:14Z,
2017-06-18T14:06:33Z,
2017-06-11T13:48:45Z,
2017-06-18T08:01:20Z,
2017-06-18T12:34:00Z,
2017-06-19T06:05:51Z,
2017-06-18T09:06:07Z,
2017-06-18T14:06:33Z,
2017-06-18T14:06:15Z,
2017-06-18T14:07:20Z,
2017-06-11T13:48:45Z,
2017-06-18T14:06:33Z,
2017-06-18T14:06:33Z,
2017-06-19T06:06:03Z,
2017-06-18T14:06:33Z
)
@ ls! pwd | (_.mtime) sorted
res3: Seq[java.nio.file.attribute.FileTime] = List(
2017-05-01T03:41:14Z,
2017-06-11T13:48:45Z,
2017-06-11T13:48:45Z,
2017-06-11T13:48:45Z,
2017-06-11T13:48:45Z,
2017-06-18T08:01:20Z,
2017-06-18T09:06:07Z,
2017-06-18T12:34:00Z,
2017-06-18T14:06:15Z,
2017-06-18T14:06:33Z,
2017-06-18T14:06:33Z,
2017-06-18T14:06:33Z,
2017-06-18T14:06:33Z,
2017-06-18T14:06:33Z,
2017-06-18T14:07:20Z,
2017-06-19T06:05:51Z,
2017-06-19T06:06:03Z,
2017-06-21T12:24:41Z,
2017-06-21T12:29:05Z
)
@ ls! pwd | (_.mtime) min
res4: java.nio.file.attribute.FileTime = 2017-05-01T03:41:14Z
@ ls! pwd | (_.mtime) max
res5: java.nio.file.attribute.FileTime = 2017-06-21T12:29:05Z
@ ls! pwd maxBy (_.mtime)
res6: Path = root/'Users/'lihaoyi/'Dropbox/'Github/'Ammonite/".idea"
PS C:\Users\erk> Get-ChildItem | Sort-Object LastWriteTime | Select-Object -first 1
Directory: C:\Users\erk
Mode LastWriteTime Length Name
---- ------------- ------ ----
d----- 17-06-2016 16:08 TracingAlso I think PS commands aren't case sensitive, though for readability one would probably want to keep the camelcase anyway.
As far as pretty-printing the final output to the user, in my opinion that is something that is better handled at terminal level instead of the shell.
Of course these are just comments based on how I imagine a reasonable object shell would function, and I really would like to hear more views on this subject because it is very likely that I might have overlooked something essential.
I statred this to show how easy it was, but it quickly became pretty hacky.
> stat --format='%z' *
2016-05-27 12:39:46.559137232 -0300
2015-07-26 14:37:51.714193856 -0300
2016-04-15 19:55:33.329346654 -0300
2016-03-21 02:59:05.377041620 -0300
2015-11-22 19:27:56.868541801 -0300
> stat --format='%z' * | sort -n | head -n 1
2015-07-26 14:37:51.714193856 -0700Being able to work on my own car is an important freedom, even if I don't know anything about cars. I can get a knowledgeable friend to look at it, or I can hire a mechanic, and it doesn't have to be a mechanic from the manufacturer.
Also, it doesn't matter how much of the population uses their freedom for it to be important.
You've just said "if you can't make an informed decision, then you should make the choice that I agree with" (from other comments, you clearly are someone who does care about licensing, and don't like the GPL). It works just as well both ways. You even slipped in some loaded propaganda words ("restrictive viral"), just in case anyone had any doubt that you weren't offering objective advice.
Fundamentally, there's a choice, and there's no getting around that with "if you don't care" defaults.
> You even slipped in some loaded propaganda words
GPL proponents describe the GPL as viral, and I'd be surprised if anyone tried to argue that it's not a restrictive license, so I'd hardly call that "propaganda".
> If you don't care about licensing, GPL is a fantastic choice.
This is incredibly wrong, and it's kind of horrifying to me to see you try and trick uninformed people into picking something viral and restrictive like the GPL. You should be ashamed of yourself.
If you don't care about licensing, do not pick GPL. The license exists specifically for people that believe in what that license does, and it's literally the worst possible license choice for someone who doesn't care about the license.
Why is that? Because with the GPL you can't as easily capitalize commercially on the work of others at no cost? Or because picking a more permissive permissive license means that other people can keep their improvements to the source you provided proprietary?
The GPL seems like the safest choice if you don't know what to pick.
But I would actually recommend cc0. Especially for small, trivial projects - I guess I can see that people want attribution - but I think cc0 can sometimes makes things much easier. This is especially true for projects that are meant to be educational/example code.
It clears up any and all confusions about copy-pasting and so on. The main counterpoint is that mit, apache (Apl) and 2/3-clause bsd are all well-known.
If I had to recommend just one licence it would probably be Apl, due to the patent grant.
I'm not familiar with the Apl license.
My personal preference at this point is to dual-license under both The Apache License, Version 2.0 and MIT. The Apache license has a patent grant and it also has the nice property where it doesn't include the name of the copyright holder so you only need one copy of the license even if you're using 20 different Apache-licensed libraries. And the dual license under MIT is just because MIT is a simpler and more well-known license, so this is to avoid scaring off anyone who isn't familiar with the Apache license.
dir | sort LastWriteTime | select -first 1
GPL is the worst choice because it's basically the most restrictive license I can think of, and it's intentionally viral, which makes GPL-licensed software dangerous to work with (the source of) by anyone who hasn't already bought into the GPL ecosystem.
https://opensource.org/licenses/apachepl.php (Uses APL)
https://en.wikipedia.org/wiki/Apache_License (Uses AL)
[Ed: Or indeed, just an old misspelling/error that I've repeated here. Anyway - I meant the Apache License v2]
That'd be a tolerable graduated approach where you get benefits even if not every tool support it.
With "jq", I'm already increasingly leaning on JSON for this type of role.
It'd need to be very non-invasive, though, or all kinds of things are likely to break.
Maybe an IOCTL to put a pipe into "packet mode" in which rather than just reading/writing raw bytes you send/receive Type-Length-Value packets... If you put your pipe in packet mode, and the other end then reads or writes without enabling packet mode, the kernel can send a control message to you saying "other end doesn't support packet mode" and then you can send/receive data in your default format. Whereas, if both ends enter packet mode before reading/writing, then the kernel sends a control message to one end saying "packet mode negotiated", and which triggers the two ends to exchange further control messages to negotiate a data format, before actually sending the data. (This implies pipes must be made bidirectional, at least for control packets.)
I don't mean to argue there is no value in specialised adapters, but I believe the default should be as general as can be. Let me worry about parsing/formats at the application level and get me simple underlying pipes. If I need something specific I should be prepared to dig into docs and find out what I need anyway, so default text vs install or explicitely configure your system to use something else seems like a sane feature/complexity segregation in the general case.
EDIT: good quote from another thread to illustrate my point: > Removing the responsibility for reliable communication from the packet transport mechanism allows us to tailor reliability to the application and to place error recovery where it will do the most good. This policy becomes more important as Ethernets are interconnected in a hierarchy of networks through which packets must travel farther and suffer greater risks.
replace Ethernet with pipes and the point still has merit IMO. Lifted off of https://news.ycombinator.com/item?id=14675115
Which could still be ergonomic if all the common piping programs supported some specific collection of formats and there was a relatively robust format-converting program.
Look at FreeBsd's libxo. It's supported by most of the base system.
(Not to diminish libxo --it looks pretty cool, and I didn't know about it before-- just curious.)
But given that it's there, I'll certainly consider it when writing tools, and consider supporting the command-line option/env var even if/when I don't use the implementation...
Good point, but jq handles this already. If the payload is an array of object, simply `jq -c '.[]'` to get an object per line
Note that when such software is used, numbers that are
integers and are in the range [-(2**53)+1, (2**53)-1]
are interoperable in the sense that implementations will
agree exactly on their numeric values.
The recommended use is to have big numbers as strings, since it's the only way to reliably pass them around. (Yes, this is kind of horrible.)
Start with record based streams first. Text streams requires [buggy] parsing to be implemented everywhere. It should be possible to have escaped record formats that allow the right side of the pipe to use AWK style $1, $2, $3, etc.
After removing the need to parse the fields, the next priority, imo, would be to introduce integral types so the actual data itself doesn't need to be parsed. u32 on the LHS can just be 4 bytes and then read out on the RHS as 4 bytes. This could save a lot of overhead when processing large files.
Only then would I want to get into hierarchies, product types, sum types, etc.
Half of all parsing work consists of splitting things into records, by lines, delimiters or whitespace. That's where the great escaping headache begins.
In a better shell the following command would Just Work™:
> find | rm %path/%filename
It also does one thing wrong: it uses objects (i.e. the stuff that carries behavior, not just state). This ties it to a particular object model, and the framework that supports that model.
What's really needed is something simple that's data-centric, like JSON, but with a complete toolchain to define schemas and perform transformations, like XML (but without the warts and overengineering).
I do not see this as a given. It's a matter of abstraction vs performance tradeoff and that is highly subjective. Unless you pioneer a new standard form for complex object notation this'll just end up back to a format flamewar.
(And if we go that way, I'd argue for s-exprs or -dare I say it- xml)
I remember finding jq a few weeks ago and thinking "wow, this will probably come in handy for a specific kind of situation" and filing it mentally for later use, but I haven't used it for anything yet so I'm not super familiar with the extent of it's features.
I have been using a lot of JSONata one liners to replace several procedural functions that were doing data transforms on JSON objects, and I'm very impressed. It's a querying library but it's Turing complete - it has lambdas, it can save references to data and functions as variables, etc.
It also seems relatively new/unknown; I've found hardly any blogs or forums mentioning it. The developer is active - he fixed a bug report I submitted in less then a day.
I'd love to have that kind of functionality in a CLI tool. Maybe jq is equally powerful, I don't know.
I haven't had time to run any performance analysis on JSONata and haven't found anyone else online who's done any yet. I'm very curious how its queries compare to efficiently implemented procedural approaches.
As an example, basic manipulation is just:
`echo '{"age":10}' | json -e 'this.age++' #=> {"age": 11}`
What would it be? Is there a real alternative to XML with those features out there? I don't think so.
When you would want to have the features of XML and would design it from scratch I'm quite sure it would have the complexity of XML again.
Usually implementing some functionality yields every time the same level of complexity regardless of how you implement it (given that none of the implementations isn't out right stupid of curse).
I don't think so. The problem with the XML stack is that it has been designed with some very "enterprisey" (for the lack of better term) scenarios in mind - stuff like SOAP. Consequently, it was all design by committee in the worst possible sense of the word, and it shows.
To see what I mean, take a look at XML Schema W3C specs. That's probably the worst part of it, so it should be readily apparent what I mean:
https://www.w3.org/TR/xmlschema11-1/ https://www.w3.org/TR/xmlschema11-2/
The other problem with XML is that it's rooted in SGML, and inherited a lot of its syntax and semantics, which were designed for a completely different use case - marking up documents. Consequently, the syntax is overly verbose, and some features are inconsistent for other scenarios - for example, if you use XML to describe structured data, when do you use attributes, and when do you use child elements? Don't forget that attributes are semantically unordered in XDM, while elements are ordered, but also that attributes cannot contain anything but scalar values and arrays thereof.
Oh, and then don't forget all the legacy stuff like DTD, which is mostly redundant in the face of XML Schema and XInclude, except it's still a required part of the spec.
I guess the TL;DR version of it is that XML today is kinda like Java - it was there for too long, including periods when our ideas of best practices were radically different, and all that was enshrined in the design, and then fossilized in the name of backwards compatibility.
One important takeaway from XML - why it was so successful, IMO - is that having a coherent, a tightly bound spec stack is a good thing. For example, with XML, when someone is talking about schemas, you can pretty much assume it's XML Schema by default (yes, there's also RELAX NG, but I think calling it schema is a misnomer, because it doesn't delve much into semantics of what it describes - it's more of a grammar definition language for XML). To transfer XML, you use XSLT. To query it, you use XPath or XQuery (which is a strict superset). And so on. With JSON, there's no such certainty.
The other thing that the XML stack didn't quite see fully through, but showed that it could be a nice thing, is its homoiconicity: e.g. XML Schema and XSLT being XML. Less so with XPath and XQuery, but there they had at least defined a canonical XML representation for it, which gives you most of the same advantages. Unfortunately, with XML it was just as often a curse as it was a blessing, because of how verbose and sometimes awkward its syntax is - anyone who wrote large amounts of XSLT especially knows what I'm talking about. On the other hand, at least XML had comments, unlike JSON!
Hey, maybe that's actually the test case? A data representation language must be concise enough, powerful enough, and flexible enough to make it possible to use it to define its own schema and transformations, without it being a painful experience, while also being simple enough that a single person can write a parser for it in a reasonable amount of time.
echo $somejson-jobspec | ifconfig
ifconfig em0 inet 192.02.1/24 aliasAssigns is another one (for the non-Amiga aware that stumble on this, on the Amiga, I'd refer to my files with "Home:", but unlike on a Unix/Linux, Home: is not an environment variable that needs to be interpreted like $HOME or something that needs to be expanded like "~" - it is recognised by the OS as a valid filesystem path, assigned at runtime; similarly, instead of having a $PATH that needs to be interpreted, all my binaries would be accessible via "C:" for "command" - "C:" is an assign made up of multiple actual directories, one of which would typically be Sys:C, where Sys: is the System volume, and Sys: itself is an assign pointing to whatever drive you booted; Assigns are like dynamic symlinks with multiple targets, or like $PATH's interpreted by the OS)
"Defining a standard format" hasn't been a successful practice in the Unix world. Many standards consist essentially of the bare minimum that everybody can agree with.
Unix command-line interfaces are already structured (as a list of strings), and more structure would be hard to support at the binary level. There are too many possibilities of doing that, and most CLI programs wouldn't even need that.
Then you are essentially relying on the de-facto standard of not rolling your own argument parsing, as opposed to some product of a standards committee.
Still it's too opinionated to be applicable to all programs. And it's by far not structured enough to support automated completions.
Every programmer goes through this phase of trying to abstract what can't be abstracted. Essentially for non-trivial programs you need to encode what you want yourself. You can't write a library that is suitable for the infinitely many thinkable programs.
By the way, even handcoded completions are, often enough, more confusing than helpful to me (and not because they are handcoded). I've disabled them entirely.
And I'd go from "kind of horrible" to just "horrible".
Integral bit limits are an implementation detail that every language has a way to overcome - they shouldn't be built into an encoding spec.
As pointed out upstream, we're dealing with a lot of data these days, and such limitations will only cause JSON to become marginalized or complicated with implementation-dependent workarounds, like integers in strings.
Seems like a standardized S-expression format would fit the bill.
You could even try to make it work with existing XML tools by specifying a way to generate XML SAX events from the S-expressions.
JSON is actually pretty decent, if only it had comments, richer data types, and some relaxed rules around syntax (e.g. allow trailing commas and unquoted keys).
Huh? Can you give some examples? I'm on zsh, and except for broken auto-generated shell completions like that provided by ripgrep, I've found zsh completions to be incredibly competent. Much more competent than myself usually.
The context sensitivity is just very confusing. Sometimes completion hangs, maybe because an SSH connection is made in the background, or the completion is just not very efficient.
Then sometimes I have a typo and get the weirdest suggestions and it's much harder to track down the error statically than just running the program and get a nice error message.
Then sometimes I am more intimate with the complexities of the command-line invocation than the completion script can appreciate, and get no completion, when all I need is just a stupid local file completion. This results in the (untrue) assumption a file wasn't there, which easily leads to further confusion.
No, thanks. I know how to use the tools that I use. Dear completion, just help me with the files on my disk (which is the fast-changing variable in the game) and let me type commands as I see fit.
Interesting. I use too many different tools too rarely to remember all their options, so being able to type -, hit tab and see a list of possibilities with their descriptions is simply more frictionless than having to pull up the command's man page and search through it. The cases where the suggestions don't work don't bother me, because it just means I don't save time compared to no completions at all.