Probably because I’m not a lisp person but the syntax is just ugly and not intuitive. It would look much better as a yaml file and I don’t even really like yaml either.
I felt the same but after reading this[1] and following along with the REPL it finally started to click.
There are actually much less rules than "normal" programming languages. I had started to write my own basic functions that would be in a "standard library" (trim(), trunc(), remove() etc) and got the hang of it after a couple hours.
The only thing I don't like about the language for "serious" work on massive projects is missing static types (may make it less readable though..), and the tooling (most people lean on Emacs) could be better.
So I'm guessing there's some additional conventions for function naming, besides appending ? to the name for boolean return and ! for functions that mutate.
If you know Lisp or Haskell then Emacs and XMonad are great. If you don't, then you just get lost trying to configure them. Nix lang is a much simpler DSL with affordances like nice list syntax. It may be less powerful than lisp but it's easy to edit and (relatively) quick to learn. Similar to vimscript, which sucks, but it's amenable to easy edits for the unwashed masses.
My issue with Nix-lang is that it's somewhere between declarative and uhm…not declarative?
Certain sections of nix files have special meaning (config), certain functions only work in those sections. Nice features like `//` for merging dicts goes out of the window as soon as you have nested dict, which is nearly every time.
It's poorly documented, “standard library” documentation is even worse. It's impossible to navigate because everything is mashed together in `nixpkgs`. Often show no examples on how to use a function and just say `it takes blahblah`, but what is blahblah?
Well, yes, it fixed it when I've discovered this function a while ago. That's just an example.
That's what I'm bitching about - discovering documentation sucks because nix-lang is a very niche language and `nixpkgs.lib` is mostly undocumented. That makes finding how to do something in it is harder compared if to any other language.
With homebrew, it's just ruby scripts. You write ruby, you can ask some ruby question from someone who never wrote a formula and get an answer because that's a general purpose language.
With guix, it's not the best, but it's still just GNU Guile, it's been around for almost 30 years. Yeah, it's probably not very popular, but it's still a general purpose language that has uses outside Guix.
How familiar are you with Lisps? I heard somewhere that it's easier for a complete beginner to start learning programming with lisps than with traditional languages. I started with more mainstream languages, but my experience tends to agree with that observation. The small set of various lisp forms and their semantics are easy to learn and reason about, compared to synatx and semantics of more traditional languages. Same when s-expressions are used for representing data. The syntax closely matches the logical structure of a program or data.
Keeping this in mind, I find the Guile scheme syntax used by Guix quite intuitive and pleasant. It reduces the cognitive overhead to configure the system, at least for me.
I am not a lisp person, but it is just a configuration file with key value pairs and lists, mostly copy pasted from the documentation or other ppl configurations. A file with all configs in the same place in an unified way
Also each configuration file in Linux has already has their differences and quirks
- the module paths a bit weird (I’d find slash or dot separated more obvious)
- some values needed to be constructed with a call to list
- weird dsl for building was mixed in there
- it’s probably not obvious what should be string/symbol/whatever
I’m not sure anything should change though. It still feels a bit weird to me that it’s a program generating the package rather than a more direct ‘just data’ format.
- the module paths a bit weird (I’d find slash or dot separated more obvious)
There's no special syntax for any of those dot slash whatever stuff. (Program item) paths are always lists (like in CSS selectors). Likewise we don't use shell strings and then have to weirdly escape them, we just use an argv list to begin with. And so on. What's the use in pretending it's something it's not?
- some values needed to be constructed with a call to list
It depends on how good you are with quoting; if you want to avoid quasiquote, "list" is easier to understand. Otherwise, (almost) no values need to be constructed with a call to "list".
(list 1 2 3) is equal to `(1 2 3)
(list 1 2 b) is equal to `(1 2 ,b)
(list 1 'b b) is equal to `(1 b ,b)
>- weird dsl for building was mixed in there
If you mean what I think you mean then it's a program running in the build container (in an extra process) (so it's quoted in the scm file of guix).
- it’s probably not obvious what should be string/symbol/whatever
I’m not sure anything should change though. It still feels a bit weird to me that it’s a program generating the package rather than a more direct ‘just data’ format.
It will always end up like that, even in packaging systems that start with a "just data" config format. They will always grow their own weird language for #if, #cfg, function calls and so on in the config format. Then they have weird generator scripts generating the config files, and there they are right where we are, just shittier.
To the last point: since it is a lisp, data = code and all that. Fundamentally I think that is at the heart of a lot of the power here with package definitions and the system itself being the same.
Ok, so mostly just variations on the “unfamiliar with lisp” theme. Though I have to say that it would be a bit silly to invent a new way to write lists just to name packages, when Lisp already has an excellent way of writing lists. :)
Oh, and how can a package manager avoid dealing with build systems? There are almost as many different build systems as there are packages!
I was trying to answer the question of why the lisp config might be difficult to read so I deliberately tried to not rely on my own intuition about how lisps work. In particular, I think it is possible to design a format for s-expression package definitions that is more approachable to people who don’t know lisp.
I continue to find it slightly odd that the package definition is not some serialisation of a package object but rather a full program that outputs a package object, and I think this is the root of a bunch of the confusing things about the definition. Consider that the commenter at the top of this thread thought yaml might be preferable. I think that means they didn’t realise they were looking at a program outputting the package definition but rather that they thought they were just looking at the definition itself.
If the whole thing were just data instead of data that’s actually code whose evaluation produces data, I think things would be more obvious. For example, some symbols are just syntax (e.g. in the alist syntax for constructing the package definition) whereas others are references to values of which some are other packages, some are just scheme functions, and some are guix-specific functions. And symbols have other meanings in the build-steps reader macro.
Building package definitions in this way can also make errors harder to pinpoint as the author can write any program they like rather than being restricted to a more limited configuration language. Needing to evaluate programs to get packages can also, I think, make the collection of all packages as a whole pretty opaque and hard to reason about compared to e.g. being able to have a database that contains all the package definitions.
I don’t think the ‘unfamiliar with lisp’ argument is good. I’m pretty familiar with lisp (though not so much guile/scheme) and I’ve been writing it for over ten years and I think this way of specifying packages is not great in the average case, though perhaps there are some complexities that cannot be handled without this general mechanism.
YAML’s excesses are exactly why a real programming language is preferable to a mere serialization format. Aliases and overrides are only useful in YAML because it is not a real programming language.
As for error messages, I don’t think that using a real programming language forces the error messages to be bad, or to be too generic. If the error messages are not good it is only because nobody has put in the time and elbow grease to make them good, not because of any fundamental limitation of turing–complete languages.
Macros and function calls look the same and have completely different semantics. And everything else looks the same too. Lisp is a language that is nice to work with when you want to write an interpreter for it, but horrible to read as a normal user. Half your time is spend counting parenthesis and trying to figure out how and what to quote.
I do actually prefer s-expressions to JSON, but only when used as pure data. Once you turn it into scripting language it gets ugly fast.
but horrible to read as a normal user. Half your time is spend counting parenthesis and trying to figure out how and what to quote.
Which is why a good text editor will balance parentheses automatically and highlight macros. That being said, it is well known that macros can be abused and overused. It is considered bad style to use macros if a function would do the job too.
That being said, it is well known that macros can be abused and overused.
Which is what Guix is doing. Just look at (package), why isn't that a function taking an associated list? It's this kind of ad hoc DSL magic that makes Lisp-like languages incredible hard to read, since you never know what you are looking at.
Notice how the alist has to be backquoted so that you can put a comma in front of everything that needs to be evaluated, and how every entry in the alist has to be a pair rather than a list which requires a dot on every line. Which would you rather type out a hundred thousand times? Which would you prefer to teach to new contributors? Which would you prefer to answer questions about on a mailing list?
Which would you rather type out a hundred thousand times?
Neither. But that proofs my point, Lisp is unreadable for the average user. If your first instinct is to not use the language itself, but write your own DSL on top of it to make it readable, maybe that language ain't such a good choice.
But the whole point of Scheme is that the syntax is simple enough that you _can_ do metalinguistic abstraction. That was a deliberate design choice, not an accident. In most other languages you have to stoop to using some other parser and interpreter for data files, rather than reusing the excellent parser and interpreter that you already have for Scheme itself.
Plus, you can’t assume that using JSON or YAML will give your users some kind of magical intuition bonus; you’ll still have to train them to use JSON/YAML correctly. I have a friend (who isn’t a software engineer) who needed to do some work on JSON files, and it was pretty clear that he was just cargo–culting it. He was only doing it to accomplish some larger goal, not for the joy of knowing the JSON syntax. That’s a hurdle you will face no matter what you do.
I am not complaining about those abstractions being possible, I am complaining about them being necessary for doing basic stuff that every other modern language solves with a builtin dictionary datatype. The more you use those abstractions the worse your error messages will get and the harder it will be to understand what is going on.
JSON would at least work consistently and don't randomly redefine the meaning of the language midway through a config file. YAML numerous issues of its own, so I'd avoid that if possible.
This isn't a Guix specific problem, the GNU project has tried to make Guile a thing for the last 20 years or so, and it just never looked especially elegant to me in any context and never really gained any real adoption in the wild either.
And when it comes to package configuration, it's just an unnecessary issue, we already had Nix, which comes with it's own JSON-like language specifically build for this task and that is much nicer to work with than Scheme, because it's configuration language first, not a general purpose programming language turned into one via macros. Using Scheme instead just doesn't improve the situation in any way in my eyes, it just creates a lot of additional problems.
Comments
Probably because I’m not a lisp person but the syntax is just ugly and not intuitive. It would look much better as a yaml file and I don’t even really like yaml either.
I felt the same but after reading this[1] and following along with the REPL it finally started to click.
There are actually much less rules than "normal" programming languages. I had started to write my own basic functions that would be in a "standard library" (trim(), trunc(), remove() etc) and got the hang of it after a couple hours.
The only thing I don't like about the language for "serious" work on massive projects is missing static types (may make it less readable though..), and the tooling (most people lean on Emacs) could be better.
So I'm guessing there's some additional conventions for function naming, besides appending ? to the name for boolean return and ! for functions that mutate.
[1]https://spritely.institute/static/papers/scheme-primer.html
I don't like lisp syntax, but honestly, I would rather use this language than whatever nix is.
It can't be a yaml file because it's essentially a program, it's a lot easier to write such things as a program.
If you know Lisp or Haskell then Emacs and XMonad are great. If you don't, then you just get lost trying to configure them. Nix lang is a much simpler DSL with affordances like nice list syntax. It may be less powerful than lisp but it's easy to edit and (relatively) quick to learn. Similar to vimscript, which sucks, but it's amenable to easy edits for the unwashed masses.
My issue with Nix-lang is that it's somewhere between declarative and uhm…not declarative?
Certain sections of nix files have special meaning (config), certain functions only work in those sections. Nice features like `//` for merging dicts goes out of the window as soon as you have nested dict, which is nearly every time.
It's poorly documented, “standard library” documentation is even worse. It's impossible to navigate because everything is mashed together in `nixpkgs`. Often show no examples on how to use a function and just say `it takes blahblah`, but what is blahblah?
Ah, so Nix needs lenses.
Edit: On the NixOS matrix I was told "there is lib.recursiveUpdate" when I mentioned your comment.
Does that fix this problem for you or improve things?
Well, yes, it fixed it when I've discovered this function a while ago. That's just an example.
That's what I'm bitching about - discovering documentation sucks because nix-lang is a very niche language and `nixpkgs.lib` is mostly undocumented. That makes finding how to do something in it is harder compared if to any other language.
With homebrew, it's just ruby scripts. You write ruby, you can ask some ruby question from someone who never wrote a formula and get an answer because that's a general purpose language.
With guix, it's not the best, but it's still just GNU Guile, it's been around for almost 30 years. Yeah, it's probably not very popular, but it's still a general purpose language that has uses outside Guix.
How familiar are you with Lisps? I heard somewhere that it's easier for a complete beginner to start learning programming with lisps than with traditional languages. I started with more mainstream languages, but my experience tends to agree with that observation. The small set of various lisp forms and their semantics are easy to learn and reason about, compared to synatx and semantics of more traditional languages. Same when s-expressions are used for representing data. The syntax closely matches the logical structure of a program or data.
Keeping this in mind, I find the Guile scheme syntax used by Guix quite intuitive and pleasant. It reduces the cognitive overhead to configure the system, at least for me.
I am not a lisp person, but it is just a configuration file with key value pairs and lists, mostly copy pasted from the documentation or other ppl configurations. A file with all configs in the same place in an unified way
Also each configuration file in Linux has already has their differences and quirks
Would you mind clarifying what part of the syntax was unintuitive?
I think when I skimmed it, I found:
- the module paths a bit weird (I’d find slash or dot separated more obvious)
- some values needed to be constructed with a call to list
- weird dsl for building was mixed in there
- it’s probably not obvious what should be string/symbol/whatever
I’m not sure anything should change though. It still feels a bit weird to me that it’s a program generating the package rather than a more direct ‘just data’ format.
There's no special syntax for any of those dot slash whatever stuff. (Program item) paths are always lists (like in CSS selectors). Likewise we don't use shell strings and then have to weirdly escape them, we just use an argv list to begin with. And so on. What's the use in pretending it's something it's not?
It depends on how good you are with quoting; if you want to avoid quasiquote, "list" is easier to understand. Otherwise, (almost) no values need to be constructed with a call to "list".
>- weird dsl for building was mixed in thereIf you mean what I think you mean then it's a program running in the build container (in an extra process) (so it's quoted in the scm file of guix).
It will always end up like that, even in packaging systems that start with a "just data" config format. They will always grow their own weird language for #if, #cfg, function calls and so on in the config format. Then they have weird generator scripts generating the config files, and there they are right where we are, just shittier.
https://en.wikipedia.org/wiki/Greenspun%27s_tenth_rule :)
To the last point: since it is a lisp, data = code and all that. Fundamentally I think that is at the heart of a lot of the power here with package definitions and the system itself being the same.
Ok, so mostly just variations on the “unfamiliar with lisp” theme. Though I have to say that it would be a bit silly to invent a new way to write lists just to name packages, when Lisp already has an excellent way of writing lists. :)
Oh, and how can a package manager avoid dealing with build systems? There are almost as many different build systems as there are packages!
I was trying to answer the question of why the lisp config might be difficult to read so I deliberately tried to not rely on my own intuition about how lisps work. In particular, I think it is possible to design a format for s-expression package definitions that is more approachable to people who don’t know lisp.
I continue to find it slightly odd that the package definition is not some serialisation of a package object but rather a full program that outputs a package object, and I think this is the root of a bunch of the confusing things about the definition. Consider that the commenter at the top of this thread thought yaml might be preferable. I think that means they didn’t realise they were looking at a program outputting the package definition but rather that they thought they were just looking at the definition itself.
If the whole thing were just data instead of data that’s actually code whose evaluation produces data, I think things would be more obvious. For example, some symbols are just syntax (e.g. in the alist syntax for constructing the package definition) whereas others are references to values of which some are other packages, some are just scheme functions, and some are guix-specific functions. And symbols have other meanings in the build-steps reader macro.
Building package definitions in this way can also make errors harder to pinpoint as the author can write any program they like rather than being restricted to a more limited configuration language. Needing to evaluate programs to get packages can also, I think, make the collection of all packages as a whole pretty opaque and hard to reason about compared to e.g. being able to have a database that contains all the package definitions.
I don’t think the ‘unfamiliar with lisp’ argument is good. I’m pretty familiar with lisp (though not so much guile/scheme) and I’ve been writing it for over ten years and I think this way of specifying packages is not great in the average case, though perhaps there are some complexities that cannot be handled without this general mechanism.
YAML’s excesses are exactly why a real programming language is preferable to a mere serialization format. Aliases and overrides are only useful in YAML because it is not a real programming language.
As for error messages, I don’t think that using a real programming language forces the error messages to be bad, or to be too generic. If the error messages are not good it is only because nobody has put in the time and elbow grease to make them good, not because of any fundamental limitation of turing–complete languages.
Macros and function calls look the same and have completely different semantics. And everything else looks the same too. Lisp is a language that is nice to work with when you want to write an interpreter for it, but horrible to read as a normal user. Half your time is spend counting parenthesis and trying to figure out how and what to quote.
I do actually prefer s-expressions to JSON, but only when used as pure data. Once you turn it into scripting language it gets ugly fast.
Which is why a good text editor will balance parentheses automatically and highlight macros. That being said, it is well known that macros can be abused and overused. It is considered bad style to use macros if a function would do the job too.
*Edit:* Guix supports JSON specifications too, though you are of course not as flexible as with Scheme: https://guix.gnu.org/manual/en/html_node/Invoking-guix-packa...
Which is what Guix is doing. Just look at (package), why isn't that a function taking an associated list? It's this kind of ad hoc DSL magic that makes Lisp-like languages incredible hard to read, since you never know what you are looking at.
Compare the package macro:
With a package function that takes an alist: Notice how the alist has to be backquoted so that you can put a comma in front of everything that needs to be evaluated, and how every entry in the alist has to be a pair rather than a list which requires a dot on every line. Which would you rather type out a hundred thousand times? Which would you prefer to teach to new contributors? Which would you prefer to answer questions about on a mailing list?Neither. But that proofs my point, Lisp is unreadable for the average user. If your first instinct is to not use the language itself, but write your own DSL on top of it to make it readable, maybe that language ain't such a good choice.
But the whole point of Scheme is that the syntax is simple enough that you _can_ do metalinguistic abstraction. That was a deliberate design choice, not an accident. In most other languages you have to stoop to using some other parser and interpreter for data files, rather than reusing the excellent parser and interpreter that you already have for Scheme itself.
Plus, you can’t assume that using JSON or YAML will give your users some kind of magical intuition bonus; you’ll still have to train them to use JSON/YAML correctly. I have a friend (who isn’t a software engineer) who needed to do some work on JSON files, and it was pretty clear that he was just cargo–culting it. He was only doing it to accomplish some larger goal, not for the joy of knowing the JSON syntax. That’s a hurdle you will face no matter what you do.
I am not complaining about those abstractions being possible, I am complaining about them being necessary for doing basic stuff that every other modern language solves with a builtin dictionary datatype. The more you use those abstractions the worse your error messages will get and the harder it will be to understand what is going on.
JSON would at least work consistently and don't randomly redefine the meaning of the language midway through a config file. YAML numerous issues of its own, so I'd avoid that if possible.
This isn't a Guix specific problem, the GNU project has tried to make Guile a thing for the last 20 years or so, and it just never looked especially elegant to me in any context and never really gained any real adoption in the wild either.
And when it comes to package configuration, it's just an unnecessary issue, we already had Nix, which comes with it's own JSON-like language specifically build for this task and that is much nicer to work with than Scheme, because it's configuration language first, not a general purpose programming language turned into one via macros. Using Scheme instead just doesn't improve the situation in any way in my eyes, it just creates a lot of additional problems.
Learn Sanskrit not BNF
Tongue in cheek :)