6e7006c061
This subtree split makes it possible for people to clone only yants (similar to the kontemplate and journaldriver branches). The subtree continues the history of the old git repository.
88 lines
2.3 KiB
Markdown
88 lines
2.3 KiB
Markdown
yants
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=====
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This is a tiny type-checker for data in Nix, written in Nix.
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# Features
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* Checking of primitive types (`int`, `string` etc.)
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* Checking polymorphic types (`option`, `list`, `either`)
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* Defining & checking struct/record types
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* Defining & matching enum types
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* Defining & matching sum types
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* Defining function signatures (including curried functions)
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* Types are composable! `option string`! `list (either int (option float))`!
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* Type errors also compose!
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Currently lacking:
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* Any kind of inference
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* Convenient syntax for attribute-set function signatures
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## Primitives & simple polymorphism
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## Structs
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## Nested structs!
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## Enums!
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## Functions!
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# Usage
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Yants can be imported from its `default.nix`. A single attribute (`lib`) can be
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passed, which will otherwise be imported from `<nixpkgs>`.
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TIP: You do not need to clone my whole repository to use Yants! It is split out
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into the `nix/yants` branch which you can clone with, for example, `git clone -b
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nix/yants https://git.tazj.in yants`.
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Examples for the most common import methods would be:
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1. Import into scope with `with`:
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```nix
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with (import ./default.nix {});
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# ... Nix code that uses yants ...
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```
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2. Import as a named variable:
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```nix
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let yants = import ./default.nix {};
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in yants.string "foo" # or other uses ...
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````
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3. Overlay into `pkgs.lib`:
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```nix
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# wherever you import your package set (e.g. from <nixpkgs>):
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import <nixpkgs> {
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overlays = [
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(self: super: {
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lib = super.lib // { yants = import ./default.nix { inherit (super) lib; }; };
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})
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];
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}
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# yants now lives at lib.yants, besides the other library functions!
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```
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Please see my [Nix one-pager](https://github.com/tazjin/nix-1p) for more generic
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information about the Nix language and what the above constructs mean.
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# Stability
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The current API of Yants is **not yet** considered stable, but it works fine and
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should continue to do so even if used at an older version.
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Yants' tests use Nix versions above 2.2 - compatibility with older versions is
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not guaranteed.
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