如何使用“nix search”搜索 Haskell 软件包？

Question

我知道我可以使用 nix-env 搜索 Haskell 包

nix-env -f '<nixpkgs>' -qaP -A haskellPackages name_of_package

但是速度很慢并且没有缓存。如果我尝试使用新命令

nix search

所有 Haskell 包都会被隐藏。

$ nix search aeson
error: no results for the given search term(s)!

是否可以使用新的

nix search

命令搜索 Haskell 包？如果是的话，怎么办？

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编辑：我在thisirc日志中找到了一些关于此问题的讨论，但我不太明白这些建议在实践中意味着什么。具体这部分：

20:49 <duairc> How do I make nix search include haskellPackages?
20:52 <ottidmes> duairc: you might try and call recurseIntoAttrs on haskellPackages
20:52 <rain1> thanks
20:52 <LnL> rain1: nix-env -f '<nixpkgs>' -qaP -A haskellPackages
20:54 <gchristensen> duairc: ^
20:54 <duairc> LnL: Thanks!
20:55 <LnL> err, wrong person
20:56 <LnL> you can also add an overlay that recurses, but that might make it
      hard to find non haskell stuff if you're searching for something else
20:56 <ottidmes> I can confirm that
      haskellPackages = super.recurseIntoAttrs super.haskellPackages; works though
20:58 <duairc> ottidmes: What do I do with that expression? Put it in
      configuration.nix somewhere? If I type "nix search ghcid" then
      will it find it?
20:59 <duairc> Ah, you're using super, so I guess it's an overlay
20:59 <clever> duairc: for `nix search` to find it, the overlay must be
      somewhere in $HOME, i forget the exact path
20:59 <clever> duairc: configuration.nix only effects nixos-rebuild and
      nothing else
21:00 <ottidmes> duairc: yeah, it should be put in your overlay that is
      also used by nix-env the like, so not nixpkgs.overlays in your
      configuration.nix as mentioned by clever, and then searching
      for e.g. nix search nix-diff will result in:
      * nixpkgs.haskellPackages.nix-diff (nix-diff)

Answer 1

按照 IRC 聊天，创建一个包含以下内容的

~/.config/nixpkgs/overlays.nix

文件：

[
  (self: super: {
    haskellPackages = super.recurseIntoAttrs super.haskellPackages;
  })
]

这是一个覆盖，将 haskellPackages 的

recurseForDerivations

属性设置为 true。

recurseForDerivations

告诉 nix 工具遍历该集合，在

nix search

的情况下搜索它。目前尚未记录，但已在here实现。

Nix wiki描述了覆盖层的放置位置，Nixpkgs手册描述了覆盖层的实际含义以及如何使用它们。

Answer 2

您可以保存结果：

nix-env -f '<nixpkgs>' -qaP -A haskellPackages 然后每次都搜索该输出？

我认为问题是

<nixpkgs>

必须在每次调用时进行评估，但是如果这是静态文件/路径 - 则不需要。

Answer 3

在 GitHub 上搜索最新内容

NixOS/nixpkgs

:

nix search nixpkgs#haskellPackages PACKAGE_NAME 即

nix search nixpkgs#haskellPackages aeson 将会产出

* legacyPackages.x86_64-linux.haskellPackages.AesonBson (0.4.1)
  Mapping between Aeson's JSON and Bson objects

* legacyPackages.x86_64-linux.haskellPackages.HsYAML-aeson (0.2.0.1)
  JSON to YAML Adapter

* legacyPackages.x86_64-linux.haskellPackages.Quickson (0.2)
  Quick JSON extractions with Aeson

* legacyPackages.x86_64-linux.haskellPackages.abeson (0.1.0.1)
  interconversion between aeson and bson

* legacyPackages.x86_64-linux.haskellPackages.activitystreams-aeson (0.2.0.2)
  An interface to the ActivityStreams specification

* legacyPackages.x86_64-linux.haskellPackages.aeson (2.1.2.1)
  Fast JSON parsing and encoding

.
.
.

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如果您在本地签出了

nixpkgs

，则会是：

nix search .#haskellPackages aeson