<<< tweak autocompletion

Author: gdementen

larray_editor/editor.py

@@ -516,7 +516,9 @@ def insert_completion(self, completion):
         cursor = self.textCursor()
         cursor.select(QTextCursor.WordUnderCursor)
         cursor.removeSelectedText()
-        cursor.insertText(completion)
+        # Insert a space if the cursor is at the end of the text
+        at_end = cursor.position() == len(self.toPlainText())
+        cursor.insertText(completion + (' ' if at_end else ''))
         self.setTextCursor(cursor)
 
     def keyPressEvent(self, event):
@@ -535,44 +537,35 @@ def keyPressEvent(self, event):
             elif event.key() == Qt.Key.Key_Escape:
                 completer_popup.hide()
                 return
-        if event.key() == Qt.Key.Key_Tab:
-            cursor = self.textCursor()
-            cursor.select(QTextCursor.WordUnderCursor)
-            prefix = cursor.selectedText()
-            self.completer.setCompletionPrefix(prefix.upper())
-            if self.completer.completionCount() == 1:
-                completion = self.completer.currentCompletion()
-                self.insert_completion(completion)
-                return
-            else:
-                # create a new cursor and move it to the start of the word
-                word_start_cursor = self.textCursor()
-                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
-                rect.setWidth(completer_popup.sizeHintForColumn(0)
-                              + popup_scrollbar_width)
-                self.completer.complete(rect)
-                return
-        elif (event.key() in (Qt.Key.Key_Enter, Qt.Key.Key_Return) and
+
+        if (event.key() in (Qt.Key.Key_Enter, Qt.Key.Key_Return) and
                 event.modifiers() & Qt.KeyboardModifier.ShiftModifier):
             query_text = self.toPlainText().strip()
             if query_text:
                 self.append_to_history(query_text)
             self.execute_sql(query_text)
             return
+        elif event.key() == Qt.Key.Key_Tab:
+            prefix = self.get_word_prefix()
+            self.completer.setCompletionPrefix(prefix)
+            if self.completer.completionCount() == 1:
+                completion = self.completer.currentCompletion()
+                self.insert_completion(completion)
+                return
+            else:
+                self.show_autocomplete_popup()
+                return
 
         cursor = self.textCursor()
-        block_number = cursor.blockNumber()
-        total_blocks = self.document().blockCount()
-
+        # for plaintext QTextEdit, blockNumber gives the line number
+        line_num = cursor.blockNumber()
         if event.key() == Qt.Key.Key_Up:
-            if block_number == 0:                 # Cursor is on the first line
+            if line_num == 0:
                 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
+            total_lines = self.document().blockCount()
+            if line_num == total_lines - 1:
                 if self.history_index < len(self.history) - 1:
                     if self.search_and_recall_history(direction=1):
                         return
@@ -581,6 +574,44 @@ def keyPressEvent(self, event):
                     self.clear()
                 return
         super().keyPressEvent(event)
+        # we need to compute the prefix *after* the keypress event has been
+        # handled so that the prefix contains the last key stroke
+        prefix = self.get_word_prefix()
+        if prefix:
+            self.completer.setCompletionPrefix(prefix)
+            num_completion = self.completer.completionCount()
+            if (0 < num_completion <= self.completer.maxVisibleItems() and
+                    not completer_popup.isVisible()):
+                self.show_autocomplete_popup()
+            elif num_completion == 0 and completer_popup.isVisible():
+                completer_popup.hide()
+
+    def show_autocomplete_popup(self):
+        # create a new cursor and move it to the start of the word, so that
+        # we can position the popup correctly
+        word_start_cursor = self.textCursor()
+        word_start_cursor.movePosition(QTextCursor.StartOfWord)
+        rect = self.cursorRect(word_start_cursor)
+        completer_popup = self.completer.popup()
+        popup_scrollbar = completer_popup.verticalScrollBar()
+        popup_scrollbar_width = popup_scrollbar.sizeHint().width() + 10
+        rect.setWidth(completer_popup.sizeHintForColumn(0)
+                      + popup_scrollbar_width)
+        self.completer.complete(rect)
+
+    def get_word_prefix(self):
+        text = self.toPlainText()
+        if not text:
+            return ''
+        cursor = self.textCursor()
+        cursor_pos = cursor.position()
+        # <= len(text) (instead of <) because cursor can be at the end
+        assert 0 <= cursor_pos <= len(text), f"{cursor_pos=} {len(text)=}"
+        word_start = cursor_pos
+        while (word_start > 0 and
+               text[word_start - 1].isalnum() or text[word_start - 1] == '_'):
+            word_start -= 1
+        return text[word_start:cursor_pos]
 
     def search_and_recall_history(self, direction: int):
         if not self.history: