nix-super/doc/manual/rl-next/repl-doc-renders-doc-comments.md
2024-07-15 19:56:40 +02:00

53 lines
1.3 KiB
Markdown

---
synopsis: "`nix-repl`'s `:doc` shows documentation comments"
significance: significant
issues:
- 3904
- 10771
prs:
- 1652
- 9054
- 11072
---
`nix repl` has a `:doc` command that previously only rendered documentation for internally defined functions.
This feature has been extended to also render function documentation comments, in accordance with [RFC 145].
Example:
```
nix-repl> :doc lib.toFunction
Function toFunction
… defined at /home/user/h/nixpkgs/lib/trivial.nix:1072:5
Turns any non-callable values into constant functions. Returns
callable values as is.
Inputs
v
: Any value
Examples
:::{.example}
## lib.trivial.toFunction usage example
| nix-repl> lib.toFunction 1 2
| 1
|
| nix-repl> lib.toFunction (x: x + 1) 2
| 3
:::
```
Known limitations:
- It currently only works for functions. We plan to extend this to attributes, which may contain arbitrary values.
- Some extensions to markdown are not yet supported, as you can see in the example above.
We'd like to acknowledge Yingchi Long for proposing a proof of concept for this functionality in [#9054](https://github.com/NixOS/nix/pull/9054), as well as @sternenseemann and Johannes Kirschbauer for their contributions, proposals, and their work on [RFC 145].
[RFC 145]: https://github.com/NixOS/rfcs/pull/145