hindent

# hindent [![Hackage](https://img.shields.io/hackage/v/hindent.svg?style=flat)](https://hackage.haskell.org/package/hindent) [![Haskell Cabal](https://github.com/mihaimaruseac/hindent/actions/workflows/presubmit-cabal.yaml/badge.svg)](https://github.com/mihaimaruseac/hindent/actions/workflows/presubmit-cabal.yaml) [![Haskell Stack](https://github.com/mihaimaruseac/hindent/actions/workflows/presubmit-stack.yaml/badge.svg)](https://github.com/mihaimaruseac/hindent/actions/workflows/presubmit-stack.yaml) [![OpenSSF Scorecard](https://api.securityscorecards.dev/projects/github.com/mihaimaruseac/hindent/badge)](https://api.securityscorecards.dev/projects/github.com/mihaimaruseac/hindent)

Haskell pretty printer

[Examples](https://github.com/mihaimaruseac/hindent/blob/master/TESTS.md)

## Install

    $ stack install hindent

## Usage

    $ hindent --help
    hindent - Reformat Haskell source code

    Usage: hindent [--version | [--line-length ARG]
                     [--indent-size ARG | --tab-size ARG] [--no-force-newline]
                     [--sort-imports | --no-sort-imports] [--style STYLE]
                     [-X GHCEXT] [--validate] [FILENAMES]]

    Available options:
      --version                Print the version
      --line-length ARG        Desired length of lines (default: 80)
      --indent-size ARG        Indentation size in spaces (default: 2)
      --tab-size ARG           Same as --indent-size, for compatibility
      --no-force-newline       Don't force a trailing newline
      --sort-imports           Sort imports in groups
      --no-sort-imports        Don't sort imports
      --style STYLE            Style to print with (historical, now ignored)
      -X GHCEXT                Language extension
      --validate               Check if files are formatted without changing them
      -h,--help                Show this help text

hindent is used in a pipeline style

    $ cat path/to/sourcefile.hs | hindent

The default indentation size is `2` spaces. Configure indentation size with `--indent-size`:

    $ echo 'example = case x of Just p -> foo bar' | hindent --indent-size 2; echo
    example =
      case x of
        Just p -> foo bar
    $ echo 'example = case x of Just p -> foo bar' | hindent --indent-size 4; echo
    example =
        case x of
            Just p -> foo bar

## Customization

Create a `.hindent.yaml` file in your project directory or in your
`~/` home directory. The following fields are accepted and are the
default:

``` yaml
indent-size: 2
line-length: 80
force-trailing-newline: true
sort-imports: true
line-breaks: []
extensions: [
    "GHC2021",
    "ListTuplePuns",
]
```

By default, hindent preserves the newline or lack of newline in your input. With `force-trailing-newline`, it will make sure there is always a trailing newline.

hindent can be forced to insert a newline before specific operators and tokens with `line-breaks`. This is especially useful when utilizing libraries like [`servant`](https