https://github.com/lue-bird/elm-syntax-format

pretty print elm-syntax like elm-format
https://github.com/lue-bird/elm-syntax-format

ast elm elm-format elm-syntax pretty-print

Last synced: about 1 month ago
JSON representation

pretty print elm-syntax like elm-format

• Host: GitHub
• URL: https://github.com/lue-bird/elm-syntax-format
• Owner: lue-bird
• License: mit
• Created: 2024-09-11T21:52:45.000Z (3 months ago)
• Default Branch: main
• Last Pushed: 2024-11-19T23:55:23.000Z (about 1 month ago)
• Last Synced: 2024-11-20T00:29:15.375Z (about 1 month ago)
• Topics: ast, elm, elm-format, elm-syntax, pretty-print
• Language: Elm
• Homepage: https://dark.elm.dmy.fr/packages/lue-bird/elm-syntax-format/latest/
• Size: 1.94 MB
• Stars: 6
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: changes.md
  • License: LICENSE

Awesome Lists containing this project

README

        
Pretty print an [`elm-syntax`](https://dark.elm.dmy.fr/packages/stil4m/elm-syntax/latest/) tree as [`elm-format`](https://github.com/avh4/elm-format) would

(breaking lines and inserting comments in the right places).

```elm

import ElmSyntaxPrint

import ElmSyntaxParserLenient

"""

module   Sample  exposing(...)

plus2 (n)= {- this adds 2-} n

+

2

"""

    |> ElmSyntaxParserLenient.run ElmSyntaxParserLenient.module_

    |> Maybe.map

        (\syntaxModule ->

            syntaxModule

                |> ElmSyntaxPrint.module_

                |> ElmSyntaxPrint.toString

        )

-->

Just """module Sample exposing (..)

plus2 n =

    {- this adds 2 -}

    n

        + 2

"""

```

To try it out, you can

run [this node script](https://github.com/lue-bird/elm-syntax-format/tree/main/node-elm-syntax-format).

If you want to _generate_ code, better bets are [`mdgriffith/elm-codegen`](https://dark.elm.dmy.fr/packages/mdgriffith/elm-codegen/latest/) or [`the-sett/elm-syntax-dsl`](https://dark.elm.dmy.fr/packages/the-sett/elm-syntax-dsl/latest/).

## known deviations in printing

  - ranges of `of`, `exposing` and `as` are needed to determine whether they should be on the next line or at the end of last line

  - ranges of `=`, `:`, `,`, `|`, `->`, pattern `::`, the operators and the keywords are needed to determine whether comments are before or after

  - function types outputting a parenthesized function do not preserve the parens because type parens are not stored in the syntax tree

  - comments before/after parenthesized types will get eaten because type parens are not stored in the syntax tree

  - some floats in exponent representation are formatted to without it and the other way around

  - handling int (and float?) overflow (elm-format itself seems to have issues here, too https://github.com/avh4/elm-format/issues/635)

  - formatting documentation markdown

Please [report](https://github.com/lue-bird/elm-syntax-format/issues/new) others you notice <3

## performance problems?

Please [open an issue](https://github.com/lue-bird/elm-syntax-format/issues/new).