5 ms·

Taking a quick look at this, the first thing I notice is that the configuration file syntax is obtuse and nigh-illegible unless you already know what things are

Taking a quick look at this, the first thing I notice is that the configuration file syntax is obtuse and nigh-illegible unless you already know what things are, and even then it's cumbersome and looks frustrating to write. e.g. instead of systemd's simple: Exec=/path/to/ntpd -n -c /etc/ntpd.conf -u ntpd -g We have this mess: #:start (make-forkexec-constructor (list "…/bin/ntpd" "-n" "-c" "/…/…-ntpd.conf" "-u" "ntpd" "-g") #:log-file "/var/log/ntpd.log") They say you don't need to be an expert on guile scheme to build a service file, but it does seem as though you need to know things like what `'(ntpd)` means, which I assumed was some kind of identifier literal, and it seems to be what's called a 'data literal' in scheme, but I had to google to discover that since the actual guile scheme documentation didn't seem to explain that syntax at all. I get that there are benefits to being able to do more advanced scripting in a service file, but this seems like a classic example of programmers writing things for programmers and not for users (or at least, not for users who don't 'get it'). Going to chalk this up as another 'GNU reimplemented something badly because of NIH syndrome' incident and move on.

teddyh 2y ago
> the actual guile scheme documentation didn't seem to explain that syntax at all. (quote data) 'data Quoting is used to obtain a literal symbol (instead of a variable reference), a literal list (instead of a function call), or a literal vector. ' is simply a shorthand for a quote form. For example, 'x ⇒ x '(1 2 3) ⇒ (1 2 3) '#(1 (2 3) 4) ⇒ #(1 (2 3) 4) (quote x) ⇒ x (quote (1 2 3)) ⇒ (1 2 3) (quote #(1 (2 3) 4)) ⇒ #(1 (2 3) 4) Note that an application must not attempt to modify literal lists or vectors obtained from a quote form, since they may be in read-only memory. — <https://www.gnu.org/software/guile/manual/html_node/Expression-Syntax.html https://www.gnu.org/software/guile/manual/html_node/Expressi...>
f1shy 2y ago
The system is integrated into Guix, so makes sense to use s-exp for the configuration. Systemd has done things that previously were trivial very difficult. I would like to know how it fares in that arena. The syntax can just be learned.
blueflow 2y ago
I vaguely learned lisp years ago and i already prefer the guile scheme over systemd - guile correctly takes an argument vector instead of a command string which needs to be split using some obtuse shell quoting rules. Having the shell taken out of the equation is what Lennart promised but never delivered.
uludag 2y ago
I think this may be just due to unfamiliarity. Like, if that mess you shared was written as follows: { start: makeForkexecConstructor(["…/bin/ntpd", "-n", "-c", "/…/…-ntpd.conf", "-u", "ntpd", "-g"]), logFile: "/var/log/ntpd.log" } this wouldn't bat an eye. Even though I've never used Guile, just familiarity with Elisp makes that example pretty straightforward. Lisp-adjacent people would all pretty quickly grok this I presume. And I think it's also hard to claim that one is better than the other. I personally have gotten my feet wet with Guix and I would love the time to become more familiar it.
- packetlost 2y ago
  Eh, I'm a Schemer (not Guile though) but the above is dramatically less readable and, at a glance, understandable than the equivalent systemd .target file. The problem with Lisps (but especially Schemes) is there's magic everywhere that makes no sense without having a sizeable context of the program you're working in.
  - Bootvis 2y ago
    IMO in this example there seems too be to little magic.
- yencabulator 2y ago
  I would definitely bat an eye at "make fork exec constructor", regardless of what syntax sugar you sprinkle on that abomination.
- ebilgenius 2y ago
  While I agree it's hard to claim one is outright better than the other and there are a lot of factors that go into it, I do feel it's important to toss my chip in as someone who's not familiar with Lisp, Scheme, or any other functional language that I find it's syntax and layout particularly difficult to parse, let alone get started with compared to say, the INI-inspired systemd conf files. I can detail why but the mere fact that I'd have to learn an entire functional programming language (no matter how "easy/simple" it's claimed to be) to be able to competently edit a service file is a huge immediate turn-off for me.
vvillena 2y ago
You don't have to be an expert, but knowing the basics of Lisp helps. The full definition of the example "ntpd" service is clear to read. > the actual guile scheme documentation didn't seem to explain that syntax at all It does, here: https://www.gnu.org/software/guile/manual/html_node/Expression-Syntax.html#index-quote https://www.gnu.org/software/guile/manual/html_node/Expressi... It's a basic concept of Lisp. Everything is evaluated, unless quoted. Code is data is code!
- baq 2y ago
  > Code is data is code! Which nowadays is 'yaml is code is yaml is code is yaml' in the devops world. The wheel turns.
  - nine_k 2y ago
    ...only with more parsing gotchas :(
  - davexunit 2y ago
    I tell ya, it was sometimes difficult to be a lisp guy doing devops full-time.
baq 2y ago
Guile has been the scripting language of choice for GNU before the Internet was called Internet. It hasn't even been disliked, it's been simply ignored, for the most part.
- kstrauser 2y ago
  I know that's true, having heard it talked about a lot over the years. But why, though? What is it about Guile that made GNU pick it over CL or Scheme (or TCL or Lua or...)? NM, answered my own question. It’s literally Scheme.
  - pkkm 2y ago
    > TCL I actually know the answer to that one! > The principal lesson of Emacs is that a language for extensions should not be a mere "extension language". It should be a real programming language, designed for writing and maintaining substantial programs. Because people will want to do that! > Another lesson from Emacs is that the way to make sure an extension facility is really flexible is to use it to write a large portion of the ordinary released system. If you try to do that with Tcl, you will encounter its limitations. > Tcl was not designed to be a serious programming language. It was designed to be a "scripting language", on the assumption that a "scripting language" need not try to be a real programming language. So Tcl doesn't have the capabilities of one. It lacks arrays; it lacks structures from which you can make linked lists. It fakes having numbers, which works, but has to be slow. From Why you should not use Tcl by Richard Stallman [1]. [1] https://vanderburg.org/old_pages/Tcl/war/0000.html https://vanderburg.org/old_pages/Tcl/war/0000.html
    - kstrauser 2y ago
      Brilliant. That's exactly the kind of information I was missing. I don't know enough about Tcl to opine on whether he was right, but if that's what RMS thought about it, I can see why he'd push back hard against it..
  - Pay08 2y ago
    Guile is an implementation of Scheme. As for why not CL, Stallman has expressed his dislike for CL, especially as a scripting language a lot of times over the years. Which is pretty funny because a lot of the criticisms he has about it (like the namespace system and keyword arguments) are in Guile now.
NeutralForest 2y ago
I mean, they're pretty much the same right? You can't abstract away the services and you need to pass arguments to the executable (ntpd in this case). I don't see more or fewer issues, but I also don't see the value to using Scheme instead of a conf. file like format. At the end, there's talk about adding the possibility to live reconfigure services, which is pretty cool but I don't really see what kind of users are targeted by that use-case, at least not regular users like me who's running Linux on a single laptop. The link at the end (https://spritely.institute/news/spritely-nlnet-grants-december-2023.html https://spritely.institute/news/spritely-nlnet-grants-decemb...) is IMO much more interesting since it would make it possible to orchestrate several machines and their services as well. If you have live reloading as well, I think it would make for good developer experience. My main gripe with Guile is its ergonomics and tooling: no LSP, no linter, no step-debugger that I know of and the docs are often unhelpful imo. Maybe I'm not Scheme brained enough but I think it's a shame because there are some really cool projects out there (anything https://spritely.institute/ https://spritely.institute/ really). P.S: I know that some people will tell me to get used to REPL based development which I think is fine for small-ish projects but I can't understand the flow one uses for larger projects where many components might need to talk to each other.
deleted 2y ago
[deleted]
n8henrie 2y ago
Interesting take. As a hobbyist, I get special characters and escapes wrong in systemd all the time, because they try to look like regular shell but aren't. And systemd-escape (or whatever it's called) just makes an ugly mess that makes it hard for me to read. I don't know lisp, but the idea of having each argument be part of a list (kind of like launchd's xml format) resonates with me.
IshKebab 2y ago
To be fair the Guile one is properly quoted and specifies the log file. make-forkexec-constructor is a really terrible name though, and Guile is a poor choice.
choobacker 2y ago
I agree systemd's is easier to understand, and I'm a happy systemd user. But some of Shepherd's strengths are in other examples, and it makes sense to evaluate the whole. A few examples: * if we want multiple similar services, I'd prefer writing a Guile function than using systemd templates. * the above Shepherd guile code lives lexically alongside your wider Guix guile code. AST-aware syntax highlighting and refactoring tools would treat them the same. That's pretty neat and beats having two different languages. Guix calls this g-expressions. This "one language for all your system" is pretty compelling, but Guix's feature set is a bit too far behind NixOS at the moment for me.
zamalek 2y ago
> NIH syndrome I would be using nonGuix if it booted on my machine (libre seemingly has its claws too deep), instead of Nix, precisely because Guix has far less NIH: Nix is homegrown everything. Guile was a pre-existing project (for both Guix and The Shepherd), for a pre-existing language family.
- Pay08 2y ago
  If you ever want to return to it, the nonguix ISO can be notoriously buggy. A better approach is to use the normal Guix ISO with an ethernet cable during installation and while setting up nonguix and your drivers.
  - atlintots 2y ago
    i don't have access to an ethernet cable
kazinator 2y ago
Why do we use the list function, when all the arguments are literal string objects? That wants to be a quoted literal list like this: '("…/bin/ntpd" "-n" "-c" "/…/…-ntpd.conf" "-u" "ntpd" "-g") Why isn't the configuration language mainly declarative, with executable Scheme only available other escape hatch to use as an exception rather than the rule? I don't want to worry about list versus quote in a configuration language, because they shouldn't be evaluation going on, or not by default.

teddyh 2y ago

> the actual guile scheme documentation didn't seem to explain that syntax at all. (quote data) 'data Quoting is used to obtain a literal symbol (instead of a variable reference), a literal list (instead of a function call), or a literal vector. ' is simply a shorthand for a quote form. For example, 'x ⇒ x '(1 2 3) ⇒ (1 2 3) '#(1 (2 3) 4) ⇒ #(1 (2 3) 4) (quote x) ⇒ x (quote (1 2 3)) ⇒ (1 2 3) (quote #(1 (2 3) 4)) ⇒ #(1 (2 3) 4) Note that an application must not attempt to modify literal lists or vectors obtained from a quote form, since they may be in read-only memory. — <https://www.gnu.org/software/guile/manual/html_node/Expression-Syntax.html https://www.gnu.org/software/guile/manual/html_node/Expressi...>

f1shy 2y ago

The system is integrated into Guix, so makes sense to use s-exp for the configuration. Systemd has done things that previously were trivial very difficult. I would like to know how it fares in that arena. The syntax can just be learned.

blueflow 2y ago

I vaguely learned lisp years ago and i already prefer the guile scheme over systemd - guile correctly takes an argument vector instead of a command string which needs to be split using some obtuse shell quoting rules. Having the shell taken out of the equation is what Lennart promised but never delivered.

uludag 2y ago

I think this may be just due to unfamiliarity. Like, if that mess you shared was written as follows: { start: makeForkexecConstructor(["…/bin/ntpd", "-n", "-c", "/…/…-ntpd.conf", "-u", "ntpd", "-g"]), logFile: "/var/log/ntpd.log" } this wouldn't bat an eye. Even though I've never used Guile, just familiarity with Elisp makes that example pretty straightforward. Lisp-adjacent people would all pretty quickly grok this I presume. And I think it's also hard to claim that one is better than the other. I personally have gotten my feet wet with Guix and I would love the time to become more familiar it.

packetlost 2y ago
Eh, I'm a Schemer (not Guile though) but the above is dramatically less readable and, at a glance, understandable than the equivalent systemd .target file. The problem with Lisps (but especially Schemes) is there's magic everywhere that makes no sense without having a sizeable context of the program you're working in.
- Bootvis 2y ago
  IMO in this example there seems too be to little magic.
yencabulator 2y ago
I would definitely bat an eye at "make fork exec constructor", regardless of what syntax sugar you sprinkle on that abomination.
ebilgenius 2y ago
While I agree it's hard to claim one is outright better than the other and there are a lot of factors that go into it, I do feel it's important to toss my chip in as someone who's not familiar with Lisp, Scheme, or any other functional language that I find it's syntax and layout particularly difficult to parse, let alone get started with compared to say, the INI-inspired systemd conf files. I can detail why but the mere fact that I'd have to learn an entire functional programming language (no matter how "easy/simple" it's claimed to be) to be able to competently edit a service file is a huge immediate turn-off for me.

vvillena 2y ago

You don't have to be an expert, but knowing the basics of Lisp helps. The full definition of the example "ntpd" service is clear to read. > the actual guile scheme documentation didn't seem to explain that syntax at all It does, here: https://www.gnu.org/software/guile/manual/html_node/Expression-Syntax.html#index-quote https://www.gnu.org/software/guile/manual/html_node/Expressi... It's a basic concept of Lisp. Everything is evaluated, unless quoted. Code is data is code!

baq 2y ago
> Code is data is code! Which nowadays is 'yaml is code is yaml is code is yaml' in the devops world. The wheel turns.
- nine_k 2y ago
  ...only with more parsing gotchas :(
- davexunit 2y ago
  I tell ya, it was sometimes difficult to be a lisp guy doing devops full-time.

baq 2y ago

Guile has been the scripting language of choice for GNU before the Internet was called Internet. It hasn't even been disliked, it's been simply ignored, for the most part.

kstrauser 2y ago
I know that's true, having heard it talked about a lot over the years. But why, though? What is it about Guile that made GNU pick it over CL or Scheme (or TCL or Lua or...)? NM, answered my own question. It’s literally Scheme.
- pkkm 2y ago
  > TCL I actually know the answer to that one! > The principal lesson of Emacs is that a language for extensions should not be a mere "extension language". It should be a real programming language, designed for writing and maintaining substantial programs. Because people will want to do that! > Another lesson from Emacs is that the way to make sure an extension facility is really flexible is to use it to write a large portion of the ordinary released system. If you try to do that with Tcl, you will encounter its limitations. > Tcl was not designed to be a serious programming language. It was designed to be a "scripting language", on the assumption that a "scripting language" need not try to be a real programming language. So Tcl doesn't have the capabilities of one. It lacks arrays; it lacks structures from which you can make linked lists. It fakes having numbers, which works, but has to be slow. From Why you should not use Tcl by Richard Stallman [1]. [1] https://vanderburg.org/old_pages/Tcl/war/0000.html https://vanderburg.org/old_pages/Tcl/war/0000.html
  - kstrauser 2y ago
    Brilliant. That's exactly the kind of information I was missing. I don't know enough about Tcl to opine on whether he was right, but if that's what RMS thought about it, I can see why he'd push back hard against it..
- Pay08 2y ago
  Guile is an implementation of Scheme. As for why not CL, Stallman has expressed his dislike for CL, especially as a scripting language a lot of times over the years. Which is pretty funny because a lot of the criticisms he has about it (like the namespace system and keyword arguments) are in Guile now.

NeutralForest 2y ago

I mean, they're pretty much the same right? You can't abstract away the services and you need to pass arguments to the executable (ntpd in this case). I don't see more or fewer issues, but I also don't see the value to using Scheme instead of a conf. file like format. At the end, there's talk about adding the possibility to live reconfigure services, which is pretty cool but I don't really see what kind of users are targeted by that use-case, at least not regular users like me who's running Linux on a single laptop. The link at the end (https://spritely.institute/news/spritely-nlnet-grants-december-2023.html https://spritely.institute/news/spritely-nlnet-grants-decemb...) is IMO much more interesting since it would make it possible to orchestrate several machines and their services as well. If you have live reloading as well, I think it would make for good developer experience. My main gripe with Guile is its ergonomics and tooling: no LSP, no linter, no step-debugger that I know of and the docs are often unhelpful imo. Maybe I'm not Scheme brained enough but I think it's a shame because there are some really cool projects out there (anything https://spritely.institute/ https://spritely.institute/ really). P.S: I know that some people will tell me to get used to REPL based development which I think is fine for small-ish projects but I can't understand the flow one uses for larger projects where many components might need to talk to each other.

deleted 2y ago

[deleted]

n8henrie 2y ago

Interesting take. As a hobbyist, I get special characters and escapes wrong in systemd all the time, because they try to look like regular shell but aren't. And systemd-escape (or whatever it's called) just makes an ugly mess that makes it hard for me to read. I don't know lisp, but the idea of having each argument be part of a list (kind of like launchd's xml format) resonates with me.

IshKebab 2y ago

To be fair the Guile one is properly quoted and specifies the log file. make-forkexec-constructor is a really terrible name though, and Guile is a poor choice.

choobacker 2y ago

I agree systemd's is easier to understand, and I'm a happy systemd user. But some of Shepherd's strengths are in other examples, and it makes sense to evaluate the whole. A few examples: * if we want multiple similar services, I'd prefer writing a Guile function than using systemd templates. * the above Shepherd guile code lives lexically alongside your wider Guix guile code. AST-aware syntax highlighting and refactoring tools would treat them the same. That's pretty neat and beats having two different languages. Guix calls this g-expressions. This "one language for all your system" is pretty compelling, but Guix's feature set is a bit too far behind NixOS at the moment for me.

zamalek 2y ago

> NIH syndrome I would be using nonGuix if it booted on my machine (libre seemingly has its claws too deep), instead of Nix, precisely because Guix has far less NIH: Nix is homegrown everything. Guile was a pre-existing project (for both Guix and The Shepherd), for a pre-existing language family.

Pay08 2y ago
If you ever want to return to it, the nonguix ISO can be notoriously buggy. A better approach is to use the normal Guix ISO with an ethernet cable during installation and while setting up nonguix and your drivers.
- atlintots 2y ago
  i don't have access to an ethernet cable

kazinator 2y ago

Why do we use the list function, when all the arguments are literal string objects? That wants to be a quoted literal list like this: '("…/bin/ntpd" "-n" "-c" "/…/…-ntpd.conf" "-u" "ntpd" "-g") Why isn't the configuration language mainly declarative, with executable Scheme only available other escape hatch to use as an exception rather than the rule? I don't want to worry about list versus quote in a configuration language, because they shouldn't be evaluation going on, or not by default.