current_word_range function added to pygls_utils

Makes it possible to determine the range of the word under the cursor.

jedi_language_server/pygls_utils.py

@@ -5,8 +5,9 @@
 
 
 import functools
+from typing import Optional
 
-from pygls.types import Position
+from pygls.types import Position, Range
 from pygls.workspace import Document
 
 _SENTINEL = object()
@@ -58,3 +59,25 @@ def char_before_cursor(
         return document.lines[position.line][position.character - 1]
     except IndexError:
         return default
+
+
+def current_word_range(
+    document: Document, position: Position
+) -> Optional[Range]:
+    """Get the range of the word under the cursor"""
+    word = document.word_at_position(position)
+    word_len = len(word)
+    line: str = document.lines[position.line]
+    start = 0
+    for _ in range(1000):  # prevent infinite hanging in case we hit edge case
+        begin = line.find(word, start)
+        if begin == -1:
+            return None
+        end = begin + word_len
+        if begin <= position.character <= end:
+            return Range(
+                start=Position(line=position.line, character=begin),
+                end=Position(line=position.line, character=end),
+            )
+        start = end
+    return None