pyyaml
dhall-lang
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pyyaml | dhall-lang | |
---|---|---|
16 | 113 | |
2,425 | 4,131 | |
1.3% | 0.5% | |
3.9 | 6.0 | |
12 days ago | about 2 months ago | |
Python | Dhall | |
MIT License | BSD 3-clause "New" or "Revised" License |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
pyyaml
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Cython 3.0 Released
PyYAML knew about the breakage since january 2022[0], and nothing really happened. After a year and a half with lots of alphas and betas, I don't think there is much cython could do, short of fixing PyYAML themselves.
[0]: https://github.com/yaml/pyyaml/issues/601
- Cython v3 release breaking PyYAML install well used in Python ecosystem
- Cython and pyyaml is breaking many builds
- I'm needing a hand, I do not understand some (seemingly) simple Python stuff.
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is there any difference between using string.format() or an fstring?
They did finally change the default, in PyYAML 6, after many many bugs pointing out that their previous approach is broken (including one by yours truly), so the default is now safe.
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Using Rust to not have to touch Yaml in k8s land
Note some parsers, most notably pyyaml are still at yaml 1.1, because 13 years is just not enough time to update it.
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JSON is not a YAML subset
That part of the YAML 1.2 spec is in conflict with reality, though. The base of YAML 1.1 documents is large enough that a backwards-incompatible change to default behavior is for practical purposes impossible.
YAML 1.1 was released in 2005, and 1.2 in 2009 -- only four years later. But here we are, in 2022, and YAML 1.1 is still the default (in many cases, only) version supported. That's why the "Norway problem" persists -- it's not possible for the parser to know whether an un-versioned YAML document containing "a: no" should parse the same as {"a": false} or {"a": "no"}.
Python (PyYAML) doesn't support 1.2 yet: https://github.com/yaml/pyyaml/issues/116
Ruby (Psych) ditto -- I can't even find a tracking issue to enable it.
Go (go-yaml) is a mixture of YAML 1.1 and 1.2, depending on the author's preferences.
Also, as a rough guideline, you can't have a backwards-incompatible revision of a versioned spec declare that it's the new default version, because that breaks all existing users.
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I accidentally used YAML.parse instead of JSON.parse, and it worked?
Many parsers either default to YAML pre-1.2 or do not even expose a YAML 1.2 option. PyYAML has no 1.2 option, for example. So unless Ansible is using something other than PyYAML...
Relevant (open) PR: https://github.com/yaml/pyyaml/pull/555
- AttributeError: '_io.TextIOWrapper' object has no attribute 'items'
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Why doesn't yaml allow safe_dump for decimals?
Are you perhaps talking about decimal.Decimal? https://github.com/yaml/pyyaml/issues/255
dhall-lang
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Apple releases Pkl – onfiguration as code language
Fail to see how this is any different than Dhall (https://dhall-lang.org/) other than it produces plists too.
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Pkl, a Programming Language for Configuration
Kubernetes config is a decent example. I had ChatGPT generate a representative silly example -- the content doesn't matter so much as the structure:
https://gist.github.com/cstrahan/528b00cd5c3a22e3d8f057bb1a7...
Now consider 100s (if not 1000s) of such files.
I haven't given Pkl an in depth look yet, but I can say that the Industry Standard™ of "simple YAML" + string substitution (with delicate, error prone indentation -- since YAML is indentation sensitive) is easily beat by any of:
- https://jsonnet.org/
- https://nickel-lang.org/
- https://nixos.org/manual/nix/stable/language/index.html
- https://dhall-lang.org/
- (insert many more here, probably including Pkl)
- Why the fuck are we templating YAML? (2019)
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Is Htmx Just Another JavaScript Framework?
There are underpowered languages / tools, that can only solve a problem for which they are intended poorly. But not all limited tools are like that.
Say, eBPF is prominently not Turing-complete, which allows to guarantee that a eBPF program terminates, and even how soon. Still eBPF is hugely useful in its area.
Or, say, regular expressions are limited to regular languages; in particular, they famously [1] cannot process recursive structures, like trees. Still tools like grep / ag / rg are mightily useful.
Yes, I agree that YAML is underpowered for proper k8s configuration! But it's also too powerful for its own good in other aspects [2]. I wish Google used Dhall [3] or their own purely functional config language (FCL? I already forgot the name) instead of YAML; sadly, they did not.
[1]: https://stackoverflow.com/a/1732454/223424
[2]: https://ruudvanasseldonk.com/2023/01/11/the-yaml-document-fr...
[3]: https://dhall-lang.org/
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10 Ways for Kubernetes Declarative Configuration Management
Dhall: Dhall is a programmable configuration language that combines features like JSON, functions, types, and import capabilities. Its style leans towards functional programming, so if you're familiar with functional-style languages such as Haskell, you might find Dhall to be quite intuitive.
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Berry is a ultra-lightweight dynamically typed embedded scripting language
I've been thinking along these lines but more 'strongly validated' than statically typed in the sense that you'd be better off being able to load the entire config and then produce a list of problems (and should be able to offer good editor support if done correctly).
Though https://dhall-lang.org/ demonstrates that you can statically type quite a lot of configuration to great advantage, which appears to be programmatically embeddable in multiple languages per https://docs.dhall-lang.org/howtos/How-to-integrate-Dhall.ht...
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What Is the Point of Decidability
> Where practical is in the sense of an engineer (or in their terms, a CS practitioner),
Configuration processing. E.g. I'd like my yamls to be decidable, though I'd settle for guaranteed to halt[1].
[1] https://dhall-lang.org/
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What Is Wrong with TOML?
Maybe you'd like jsonnet: https://jsonnet.org/
I find it particularly useful for configurations that often have repeated boilerplate, like ansible playbooks or deploying a bunch of "similar-but" services to kubernetes (with https://tanka.dev).
Dhall is also quite interesting, with some tradeoffs: https://dhall-lang.org/
A few years ago I did a small comparison by re-implementing one of my simpler ansible playbooks: https://github.com/retzkek/ansible-dhall-jsonnet
- Show HN: FlakeHub – Discover and publish Nix flakes
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Home Blog Better configuration languages – A talk about Dhall [video]
And to checkout Dhall: https://dhall-lang.org/
What are some alternatives?
confuse - painless YAML config files for Python
cue - CUE has moved to https://github.com/cue-lang/cue
strictyaml - Type-safe YAML parser and validator.
jsonnet - Jsonnet - The data templating language
yamllint - A linter for YAML files.
cue - The home of the CUE language! Validate and define text-based and dynamic configuration
terraform - Terraform enables you to safely and predictably create, change, and improve infrastructure. It is a source-available tool that codifies APIs into declarative configuration files that can be shared amongst team members, treated as code, edited, reviewed, and versioned.
marshmallow - A lightweight library for converting complex objects to and from simple Python datatypes.
jsonlogic - Go Lang implementation of JsonLogic
python-strict-yaml-parsing - Examples of strict yaml parsing in python
nix-gui - Use NixOS Without Coding