haskell - 从 Hoogle 命令行访问函数的文档

Question

在 the Hoogle website 上搜索功能时，可以看到与之相关的文档，例如:

mod :: a -> a -> a            infixl 7

    integer modulus, satisfying

    (x `div` y)*y + (x `mod` y) == x

Hoogle 也作为命令行可执行文件存在。据我所知，它只显示函数的签名:

~ ❯❯❯ hoogle --info Prelude.mod
Prelude mod :: Integral a => a -> a -> a

From package base
mod :: Integral a => a -> a -> a

有没有办法像在线版本一样通过命令行获取相关文档？

Answer 1

使用 -i选项。如何获得默认命令的帮助并不明显( search )；这是怎么做的:

$ hoogle search --help
Hoogle v4.2.41, (C) Neil Mitchell 2004-2012
http://haskell.org/hoogle

hoogle [search] [OPTIONS] [QUERY]
  Perform a search

Flags:
  -c --colour --color   Use colored output (requires ANSI terminal)
  -l --link             Give URL's for each result
  -i --info             Give extended information about the first result
  -e --exact            Match names exactly when searching
  -d --databases=DIR    Directories to search for databases
  -s --start=INT        Start displaying results from this point on (1 based)
  -n --count=INT        Maximum number of results to return
  -w --web[=MODE]       Operate as a web tool
  -r --repeat=INT       Run the search multiple times (for benchmarking)
Common flags:
  -? --help             Display help message
  -V --version          Print version information
     --numeric-version  Print just the version number
  -v --verbose          Loud verbosity
  -q --quiet            Quiet verbosity