Autocomplete fix: don't let -> override . autocomplete

Fixes rescript-lang#99

Author: cristianoc

Changes.md

@@ -2,6 +2,7 @@
 - Fix issue in jump-to-definition on Windows. (See https://github.com/rescript-lang/rescript-vscode/issues/98) where the wrong URI was generated.
 - Don't show file path on hover.
 - Add autocomplete for props in JSX components.
+- Autocomplete: fix issue where `->` autocomplete was overruling `.`. See https://github.com/rescript-lang/rescript-editor-support/issues/99.
 
 ## Release 1.0.6 of rescript-vscode
 This [commit](https://github.com/rescript-lang/rescript-editor-support/commit/03ee0d97b250474028d4fb08eac81ddb21ccb082) is vendored in [rescript-vscode 1.0.6](https://github.com/rescript-lang/rescript-vscode/releases/tag/1.0.6).

src/PartialParser.ml

@@ -116,6 +116,18 @@ type completable =
   | Cjsx of string list * string (* E.g. (["M", "Comp"], "id") for <M.Comp ... id *)
   | Cpipe of string (* E.g. "x->foo" *)
 
+
+let isLowercaseIdent id =
+  let rec loop i =
+    if i < 0 then true
+    else
+      match id.[i] with
+      | ('a' .. 'z' | '_') when i = 0 -> true
+      | ('a' .. 'z' | 'A' .. 'Z' | '0' .. '9' | '_') when i > 0 -> loop (i - 1)
+      | _ -> false
+  in
+  loop (String.length id - 1)
+
 let findCompletable text offset =
   let mkPath s =
     let len = String.length s in
@@ -142,7 +154,9 @@ let findCompletable text offset =
     | true -> Some (mkPath (String.sub text (i + 1) (offset - (i + 1))))
     | false -> (
       match text.[i] with
-      | '>' when i > 0 && text.[i - 1] = '-' -> loop (i - 2)
+      | '>' when i > 0 && text.[i - 1] = '-' ->
+         let rest = String.sub text (i + 1) (offset - (i + 1)) in
+         if isLowercaseIdent rest then loop (i - 2) else Some (mkPath rest)
       | '~' ->
         let labelPrefix = String.sub text (i + 1) (offset - (i + 1)) in
         let funPath = findCallFromArgument text (i - 1) in