Skip to content
/ nix-doc Public

An interactive Nix documentation tool providing a CLI for function search, a Nix plugin for docs in the REPL, and a ctags implementation for Nix script

Notifications You must be signed in to change notification settings

lf-/nix-doc

Repository files navigation

nix-doc

A Nix developer tool leveraging the rnix Nix parser for intelligent documentation search and tags generation.

Features

  • Nix plugin that adds a builtin that can display the signature and documentation for a lambda object in a friendly format
  • Command line tool that searches Nix files in a directory for functions and shows documentation for matching ones
  • Tags generator similar to ctags that can generate a vim compatible tags file for Nix source
  • High performance, threaded implementation in Rust

Setup

# nix-doc is in nixpkgs $ nix-env -i nix-doc # you can alternatively get it from git $ nix-env -i -f https://github.com/lf-/nix-doc/archive/main.tar.gz # or if you don't want to use nix (only includes the command line tool for # search and tags) $ cargo install --locked nix-doc 

Nix Plugin

To install the Nix plugin on a single-user installation of Nix, add this to your Nix config at ~/.config/nix/nix.conf after installing nix-doc with nix-env:

plugin-files = /home/YOURUSERNAMEHERE/.nix-profile/lib/libnix_doc_plugin.so 

For a multi-user installation, you will need to do something like this:

$ sudo ln -s $(nix-build '<nixpkgs>' -A nix-doc) /opt/nix-doc 

and then put this into your /etc/nix/nix.conf:

plugin-files = /opt/nix-doc/lib/libnix_doc_plugin.so 

NixOS Installation

Link the plugin file using nix.extraOptions:

{ pkgs, ... }: { nix.extraOptions = ''  plugin-files = ${pkgs.nix-doc}/lib/libnix_doc_plugin.so  ''; environment.systemPackages = with pkgs; [ nix-doc ]; }

Usage

CLI

nix-doc <command> 

nix-doc tags [dir]

Generates a vim-compatible tags file in the current directory, for all nix script files below the directory dir.

Example:

nixpkgs$ nix-doc tags nixpkgs$ file tags tags: Exuberant Ctags tag file, ASCII text, with very long lines (502) # opens vim to the function callCabal2nix nixpkgs$ vim -t callCabal2nix 

nix-doc search <regex> [dir]

Example output:

nixpkgs$ nix-doc search callPackage Call the package function in the file `fn' with the required arguments automatically. The function is called with the arguments `args', but any missing arguments are obtained from `autoArgs'. This function is intended to be partially parameterised, e.g., callPackage = callPackageWith pkgs; pkgs = { libfoo = callPackage ./foo.nix { }; libbar = callPackage ./bar.nix { }; }; If the `libbar' function expects an argument named `libfoo', it is automatically passed as an argument. Overrides or missing arguments can be supplied in `args', e.g. libbar = callPackage ./bar.nix { libfoo = null; enableX11 = true; }; callPackageWith = autoArgs: fn: args: ... # ./lib/customisation.nix:117 ───────────────────────────────────────────── Like callPackage, but for a function that returns an attribute set of derivations. The override function is added to the individual attributes. callPackagesWith = autoArgs: fn: args: ... # ./lib/customisation.nix:127 ───────────────────────────────────────────── Similar to callPackageWith/callPackage, but without makeOverridable callPackageWith = autoArgs: fn: args: ... # ./pkgs/development/beam-modules/lib.nix:7 

Nix plugin

The Nix plugin provides three builtins:

builtins.doc f

Prints the documentation of the function f to the screen. Returns null.

builtins.getDoc f

Returns the documentation message for the function f as a string (exactly the same output as builtins.doc, just as a string).

builtins.unsafeGetLambdaPos

A backport of NixOS/Nix#3912. Returns the position of a lambda, in a similar fashion to unsafeGetAttrPos for attributes.

Sample usage:

» nix repl Welcome to Nix version 2.3.7. Type :? for help. nix-repl> n=import <nixpkgs> {} nix-repl> builtins.doc n.lib.callPackageWith Call the package function in the file `fn' with the required arguments automatically. The function is called with the arguments `args', but any missing arguments are obtained from `autoArgs'. This function is intended to be partially parameterised, e.g., callPackage = callPackageWith pkgs; pkgs = { libfoo = callPackage ./foo.nix { }; libbar = callPackage ./bar.nix { }; }; If the `libbar' function expects an argument named `libfoo', it is automatically passed as an argument. Overrides or missing arguments can be supplied in `args', e.g. libbar = callPackage ./bar.nix { libfoo = null; enableX11 = true; }; func = autoArgs: fn: args: ... # /nix/store/frpij1x0ihnyc4r5f7v0zxwpslkq6s27-nixpkgs-20.09pre237807.0dc87c6e54f/nixpkgs/lib/customisation.nix:117 null 

Development

This repository is set up as a Cargo workspace with the plugin and the command line tool/library as parts.

It is not really possible to build the plugin outside a Nix shell since Nix does not provide libraries outside the shell environment. As such, it is suggested to use a nix shell while developing the plugin as follows:

$ nix-shell [nix-shell]$ cargo build [nix-shell]$ cargo check [nix-shell]$ cargo test # etc 

TODO

  • Tech: should update rnix to the latest major.

Related work

  • NixOS/nix#1652: A PR implementing basically the same thing as this tool's plugin in Nix itself, which has been deferred indefinitely due to disagreements about what syntax to use in documentation comments.
  • https://github.com/tazjin/nixdoc: A Rust tool producing DocBook documentation for Nix library functions.
  • https://github.com/mlvzk/manix: An early fork of this tool with a stronger focus on CLI usage, with support for indexing and faster search. By comparison, their CLI is better, but they don't do tags or a Nix plugin.

Project information

Everyone is expected to follow the code of conduct while participating in this project.

About

An interactive Nix documentation tool providing a CLI for function search, a Nix plugin for docs in the REPL, and a ctags implementation for Nix script

Topics

Resources

Code of conduct

Stars

Watchers

Forks

Contributors 3

  •  
  •  
  •