dhall-lang VS ShellCheck

Fail to see how this is any different than Dhall (https://dhall-lang.org/) other than it produces plists too.

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)

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/

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.

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...

> 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/

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

And to checkout Dhall: https://dhall-lang.org/

ncurse, dialog, zenity[2]. i/o buffering may be an issue [3a,3b]

Assuming using same account, use history command to show past commands[0a, 0b]

'load random example' on shellcheck using own custom examples from history command.[1]

--------

[3a] : http://www.gnu.org/software/coreutils/manual/html_node/stdbu...

[3b] : http://unix.stackexchange.com/questions/25372/how-to-turn-of...

[2] : http//funprojects.blog/2021/01/25/zenity-command-line-dialogs/

[1] : http://www.shellcheck.net/

[0a] : http://www.tecmint.com/history-command-examples/

[0b] : http://www.tecmint.com/remember-linux-commands/

web based documentation: https://www.tecmint.com/linux-commands-cheat-sheet/

commands grouped by typical usage patterns : https://www.tecmint.com/essential-linux-commands/

... #************************** Terraform ************************************* ARG TERRAFORM_VERSION=1.7.3 RUN set -ex \ && curl -O https://releases.hashicorp.com/terraform/${TERRAFORM_VERSION}/terraform_${TERRAFORM_VERSION}_linux_amd64.zip && unzip terraform_${TERRAFORM_VERSION}_linux_amd64.zip -d /usr/local/bin/ RUN set -ex \ && mkdir -p $HOME/.terraform.d/plugin-cache && echo 'plugin_cache_dir = "$HOME/.terraform.d/plugin-cache"' > ~/.terraformrc #************************* Terragrunt ************************************* ARG TERRAGRUNT_VERSION=0.55.1 RUN set -ex \ && wget https://github.com/gruntwork-io/terragrunt/releases/download/v${TERRAGRUNT_VERSION}/terragrunt_linux_amd64 -q \ && mv terragrunt_linux_amd64 /usr/local/bin/terragrunt \ && chmod +x /usr/local/bin/terragrunt #*********************** Terramate **************************************** ARG TERRAMATE_VERSION=0.4.5 RUN set -ex \ && wget https://github.com/mineiros-io/terramate/releases/download/v${TERRAMATE_VERSION}/terramate_${TERRAMATE_VERSION}_linux_x86_64.tar.gz \ && tar -xzf terramate_${TERRAMATE_VERSION}_linux_x86_64.tar.gz \ && mv terramate /usr/local/bin/terramate \ && chmod +x /usr/local/bin/terramate #*********************** tfsec ******************************************** ARG TFSEC_VERSION=1.28.5 RUN set -ex \ && wget https://github.com/aquasecurity/tfsec/releases/download/v${TFSEC_VERSION}/tfsec-linux-amd64 \ && mv tfsec-linux-amd64 /usr/local/bin/tfsec \ && chmod +x /usr/local/bin/tfsec \ && terragrunt --version #**********************Terraform docs ************************************ ARG TERRRAFORM_DOCS_VERSION=0.17.0 RUN set -ex \ && curl -sSLo ./terraform-docs.tar.gz https://terraform-docs.io/dl/v${TERRRAFORM_DOCS_VERSION}/terraform-docs-v${TERRRAFORM_DOCS_VERSION}-$(uname)-amd64.tar.gz \ && tar -xzf terraform-docs.tar.gz \ && chmod +x terraform-docs \ && mv terraform-docs /usr/local/bin/terraform-docs #********************* ShellCheck ***************************************** ARG SHELLCHECK_VERSION="stable" RUN set -ex \ && wget -qO- "https://github.com/koalaman/shellcheck/releases/download/${SHELLCHECK_VERSION?}/shellcheck-${SHELLCHECK_VERSION?}.linux.x86_64.tar.xz" | tar -xJv \ && cp "shellcheck-${SHELLCHECK_VERSION}/shellcheck" /usr/bin/ \ && shellcheck --version ...

ShellCheck: https://github.com/koalaman/shellcheck

If I want to write better shell scripts I usually run shellcheck and adjust accordingly or if I need facilities not provided by the shell i switch to a full fledged programming language. Ans oh yes, `sh` is present almost on every BSD and Linux box for free so I consider it an important thing to at least be comfortable with.

shellcheck: https://www.shellcheck.net/

When I run nix-shell at the root of the project it puts me in a Nix shell that contains, among other programs, caddy and shellcheck. Notice that in the shellHook I add the project's shell scripts to the PATH. So once I'm in the Nix shell I can, among other things:

I have also seen some projects on github like ShellCheck which first make a library, expose all the modules and then simple add that do build-depends of the final executable. Is this the recommended approach than having just one executable and adding all the modules to other-modules:?

The error checks can be pretty arcane:

   https://github.com/koalaman/shellcheck/wiki/Checks

Similar to for instance shellcheck to check the syntax of shell scripts, is there an equivalent for the set of roff commands typically used in a (Linux) man page? I'm aware that e.g. pandoc permits the conversion of an other format (e.g., org) to both roff man and roff ms.