Review

src/textual/document/_document.py

@@ -90,28 +90,6 @@ def text(self) -> str:
     def newline(self) -> Newline:
         """Return the line separator used in the document."""
 
-    @abstractmethod
-    def get_index_from_location(self, location: Location) -> int:
-        """Given a location, returns the index from the document's text.
-
-        Args:
-            location: The location in the document.
-
-        Returns:
-            The index in the document's text.
-        """
-
-    @abstractmethod
-    def get_location_from_index(self, index: int) -> Location:
-        """Given an index in the document's text, returns the corresponding location.
-
-        Args:
-            index: The index in the document's text.
-
-        Returns:
-            The corresponding location.
-        """
-
     @abstractmethod
     def get_line(self, index: int) -> str:
         """Returns the line with the given index from the document.
@@ -351,10 +329,10 @@ def get_index_from_location(self, location: Location) -> int:
         Returns:
             The index in the document's text.
         """
-        row, col = location
-        index = row * len(self.newline) + col
-        for i in range(row):
-            index += len(self.get_line(i))
+        row, column = location
+        index = row * len(self.newline) + column
+        for line_index in range(row):
+            index += len(self.get_line(line_index))
         return index
 
     def get_location_from_index(self, index: int) -> Location:
@@ -366,15 +344,15 @@ def get_location_from_index(self, index: int) -> Location:
         Returns:
             The corresponding location.
         """
-        idx = 0
-        newline_len = len(self.newline)
-        for i in range(self.line_count):
-            next_idx = idx + len(self.get_line(i)) + newline_len
-            if index < next_idx:
-                return (i, index - idx)
-            elif index == next_idx:
-                return (i + 1, 0)
-            idx = next_idx
+        column_index = 0
+        newline_length = len(self.newline)
+        for line_index in range(self.line_count):
+            next_column_index = column_index + len(self.get_line(line_index)) + newline_length
+            if index < next_column_index:
+                return (line_index, index - column_index)
+            elif index == next_column_index:
+                return (line_index + 1, 0)
+            column_index = next_column_index
 
     def get_line(self, index: int) -> str:
         """Returns the line with the given index from the document.

tests/document/test_document.py

@@ -98,3 +98,27 @@ def test_get_selected_text_no_newline_at_end_of_file_windows():
     document = Document(TEXT_WINDOWS)
     selection = document.get_text_range((0, 0), (2, 0))
     assert selection == TEXT_WINDOWS
+
+
+@pytest.mark.parametrize(
+    "text", [TEXT, TEXT_NEWLINE, TEXT_WINDOWS, TEXT_WINDOWS_NEWLINE]
+)
+def test_index_from_location(text):
+    document = Document(text)
+    lines = text.split(document.newline)
+    assert document.get_index_from_location((0, 0)) == 0
+    assert document.get_index_from_location((0, len(lines[0]))) == len(lines[0])
+    assert document.get_index_from_location((1, 0)) == len(lines[0]) + len(document.newline)
+    assert document.get_index_from_location((len(lines) - 1, len(lines[-1]))) == len(text)
+
+
+@pytest.mark.parametrize(
+    "text", [TEXT, TEXT_NEWLINE, TEXT_WINDOWS, TEXT_WINDOWS_NEWLINE]
+)
+def test_location_from_index(text):
+    document = Document(text)
+    lines = text.split(document.newline)
+    assert document.get_location_from_index(0) == (0, 0)
+    assert document.get_location_from_index(len(lines[0])) == (0, len(lines[0]))
+    assert document.get_location_from_index(len(lines[0]) + len(document.newline)) == (1, 0)
+    assert document.get_location_from_index(len(text)) == (len(lines) - 1, len(lines[-1]))