joprice/type-formatter

Scala compiler plugin to format type errors

{
  "createdAt": "2016-05-20T14:11:50Z",
  "defaultBranch": "master",
  "description": "Scala compiler plugin to format type errors",
  "fullName": "joprice/type-formatter",
  "homepage": null,
  "language": "Scala",
  "name": "type-formatter",
  "pushedAt": "2017-04-22T16:33:48Z",
  "stargazersCount": 9,
  "topics": [],
  "updatedAt": "2022-03-12T08:23:36Z",
  "url": "https://github.com/joprice/type-formatter"
}

type-formatter

Scala compiler plugin to format type errors

This is a proof of concept and has not been tested against a large project. Use at your own risk.

Note: This feature was added directly to the compiler by @VladUreche and is now available in the 2.12.2 https://github.com/scala/scala/pull/5589/files

This plugin hijacks the compiler’s error reporting to improve the readability of symbolic infix types:

Before:

[error]  found   : shapeless.::[Int,shapeless.::[String,shapeless.::[Double,shapeless.HNil]]]
[error]  required: Int
[error]   val i: Int = 1 :: "a" :: 1.1 :: HNil

After:

[error]  found   : Int :: String :: Double :: shapeless.HNil
[error]  required: Int
[error]   val i: Int = 1 :: "a" :: 1.1 :: HNil

All the credit goes to Miles Sabin and Li Haoyi, since this is just gluing together code from [pprint]!( https://github.com/lihaoyi/upickle-pprint/blob/c3227d34547fe974a47f74f537be4cf6eaefbc22/pprint/shared/src/main/scala-2.11/pprint/TPrintImpl.scala) and si2712fix.

TODO

add annotation/option to allow non-symbolic types like Xor to be printed infix