Snippet

Pretty-print regions within source code files.

Usage

import Prelude

import Data.Foldable (traverse_)
import Prettyprinter (reAnnotate)
import Prettyprinter.Render.Terminal (putDoc)
import Snippet
import Snippet.Pretty

main :: IO ()
main = do
  let
    region = Region
      { startLine = 32
      , startColumn = Just 8
      , endLine = Just 64
      , endColumn = Nothing
      , message = Nothing
      , subRegion =
          Just
            Region
              { startLine = 34
              , startColumn = Just 5
              , endLine = Just 59
              , endColumn = Nothing
              , message = Just "Denotes a region in the snippet"
              , subRegion =
                  Just
                    Region
                      { startLine = 45
                      , startColumn = Just 27
                      , endLine = Nothing
                      , endColumn = Just 31
                      , message = Just "Would default to startLine"
                      , subRegion = Nothing
                      }
              }
      }

  -- Returns Nothing if file is missing/empty or region is invalid
  mSnippet <- snippetFromFile region "README.md"

  traverse_ (putDoc . reAnnotate annToAnsi . prettySnippet) mSnippet

The above Region focuses one of the Just constructors, within the region binding, within the body of the do block. Rendering it with the default annToAnsi looks like:

Supplying an alternative annToAnsi function is how you can adjust colors.

Limitations

Drawing these regions is not an easy problem. Therefore, there are some limitations to the kind of Region values we support:

1. One top-level region per snippet,
2. A region may only have zero or one sub-region,
3. A sub-region must be contained within its parent, and
4. A sub-region cannot share start or end lines or columns with its parent

One notable consequence is that a one-line region cannot contain sub-regions.

License

This package is licensed AGPLv3. See COPYING.