<<< use prefix to search history like ipython

Author: gdementen

larray_editor/editor.py

@@ -514,7 +514,7 @@ def _handled_by_polars_sql(self, obj):
 
     def insert_completion(self, completion):
         cursor = self.textCursor()
-        cursor.select(cursor.WordUnderCursor)
+        cursor.select(QTextCursor.WordUnderCursor)
         cursor.removeSelectedText()
         cursor.insertText(completion)
         self.setTextCursor(cursor)
@@ -537,7 +537,7 @@ def keyPressEvent(self, event):
                 return
         if event.key() == Qt.Key.Key_Tab:
             cursor = self.textCursor()
-            cursor.select(cursor.WordUnderCursor)
+            cursor.select(QTextCursor.WordUnderCursor)
             prefix = cursor.selectedText()
             self.completer.setCompletionPrefix(prefix.upper())
             if self.completer.completionCount() == 1:
@@ -547,7 +547,7 @@ def keyPressEvent(self, event):
             else:
                 # create a new cursor and move it to the start of the word
                 word_start_cursor = self.textCursor()
-                word_start_cursor.movePosition(word_start_cursor.StartOfWord)
+                word_start_cursor.movePosition(QTextCursor.StartOfWord)
                 rect = self.cursorRect(word_start_cursor)
                 popup_scrollbar = completer_popup.verticalScrollBar()
                 popup_scrollbar_width = popup_scrollbar.sizeHint().width() + 10
@@ -561,21 +561,45 @@ def keyPressEvent(self, event):
             if query_text:
                 self.append_to_history(query_text)
             self.execute_sql(query_text)
-        elif event.key() == Qt.Key.Key_Up and self.history:
-            if self.history_index > 0:
-                self.history_index -= 1
-                self.setPlainText(self.history[self.history_index])
-                self.moveCursor(QTextCursor.End)
-        elif event.key() == Qt.Key.Key_Down and self.history:
-            if self.history_index < len(self.history) - 1:
-                self.history_index += 1
+            return
+
+        cursor = self.textCursor()
+        block_number = cursor.blockNumber()
+        total_blocks = self.document().blockCount()
+
+        if event.key() == Qt.Key.Key_Up:
+            if block_number == 0:                 # Cursor is on the first line
+                if self.search_and_recall_history(direction=-1):
+                    return
+        elif event.key() == Qt.Key.Key_Down:
+            if block_number == total_blocks - 1:  # Cursor is on the last line
+                if self.history_index < len(self.history) - 1:
+                    if self.search_and_recall_history(direction=1):
+                        return
+                else:
+                    self.history_index = len(self.history)
+                    self.clear()
+                return
+        super().keyPressEvent(event)
+
+    def search_and_recall_history(self, direction: int):
+        if not self.history:
+            return False
+        cursor = self.textCursor()
+        query_text = self.toPlainText()
+        cursor_pos = cursor.position()
+        prefix = query_text[:cursor_pos]
+        index = self.history_index + direction
+        while 0 <= index <= len(self.history) - 1:
+            if self.history[index].startswith(prefix):
+                self.history_index = index
                 self.setPlainText(self.history[self.history_index])
-                self.moveCursor(QTextCursor.End)
-            else:
-                self.history_index = len(self.history)
-                self.clear()
-        else:
-            super().keyPressEvent(event)
+                cursor.setPosition(cursor_pos)
+                self.setTextCursor(cursor)
+                return True
+            index += direction
+        # no matching prefix found, do not change history_index
+        return False
 
     def append_to_history(self, sql_text):
         history = self.history