Possible TextLines-based implementation

Author: michaelpj

cabal.project

@@ -10,3 +10,8 @@ tests: True
 benchmarks: True
 test-show-details: direct
 haddock-quickjump: True
+
+source-repository-package
+  type: git
+  location: https://github.com/Bodigrim/text-rope
+  tag: 0394a40476db8083a0b5fcdba2ce97b409727912

lsp/src/Language/LSP/VFS.hs

@@ -74,9 +74,10 @@ import           Data.Ord
 import qualified Data.HashMap.Strict as HashMap
 import qualified Data.Map.Strict as Map
 import           Data.Maybe
-import qualified Data.Text.Rope as URope
+import qualified Data.Text.Lines as ULines
 import           Data.Text.Utf16.Rope ( Rope )
 import qualified Data.Text.Utf16.Rope as Rope
+import qualified Data.Text.Utf16.Lines as Lines
 import           Data.Text.Prettyprint.Doc
 import qualified Language.LSP.Types           as J
 import qualified Language.LSP.Types.Lens      as J
@@ -367,15 +368,12 @@ data CodePointPosition =
 -- We need the file itself because this requires translating between code points and code units.
 codePointPositionToPosition :: VirtualFile -> CodePointPosition -> J.Position
 codePointPositionToPosition vFile (CodePointPosition cpl cpc) =
-  let utf16Text = _file_text vFile
-      -- Transcode to a code-point based rope
-      utfText = URope.fromText $ Rope.toText utf16Text
-      -- Split at the given position
-      (utfPrefix, _) = URope.splitAtPosition (URope.Position (fromIntegral cpl) (fromIntegral cpc)) utfText
-      -- Transcode the prefix to a code-unit based rope
-      utf16Prefix = Rope.fromText $ URope.toText utfPrefix
-      -- Get the length of the transcoded prefix
-      (Rope.Position cul cuc) = Rope.lengthAsPosition utf16Prefix
+  let text = _file_text vFile
+      lines = Rope.toTextLines text
+      -- Split at the given position in *code points*
+      (prefix, _) = ULines.splitAtPosition (ULines.Position (fromIntegral cpl) (fromIntegral cpc)) lines
+      -- Get the length of the prefix in *code units*
+      (Lines.Position cul cuc) = Lines.lengthAsPosition prefix
   in J.Position (fromIntegral cul) (fromIntegral cuc)
 
 -- | Given a virtual file, translate a 'J.Position' in that file into a 'CodePointPosition' in that file.
@@ -384,13 +382,12 @@ codePointPositionToPosition vFile (CodePointPosition cpl cpc) =
 -- We need the file itself because this requires translating between code unit and code points.
 positionToCodePointPosition :: VirtualFile -> J.Position -> Maybe CodePointPosition
 positionToCodePointPosition vFile (J.Position cul cuc) = do
-  let utf16Text = _file_text vFile
-  -- Split at the given location
-  (utf16Prefix, _) <- Rope.splitAtPosition (Rope.Position (fromIntegral cul) (fromIntegral cuc)) utf16Text
-  -- Transcode the preix to a code-point based rope
-  let utfPrefix = URope.fromText $ Rope.toText utf16Prefix
-      -- Get the length of the transcoded prefix
-      (URope.Position cpl cpc) = URope.lengthAsPosition utfPrefix
+  let text = _file_text vFile
+      lines = Rope.toTextLines text
+  -- Split at the given location in *code units*
+  (prefix, _) <- Lines.splitAtPosition (Lines.Position (fromIntegral cul) (fromIntegral cuc)) lines
+  -- Get the length of the prefix in *code points*
+  let (ULines.Position cpl cpc) = ULines.lengthAsPosition prefix
   pure $ CodePointPosition (fromIntegral cpl) (fromIntegral cpc)
 
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