A spot of refactoring

src/calibre/gui2/tweak_book/editor/smarts/python.py

@@ -12,8 +12,8 @@ from PyQt5.Qt import Qt
 
 from calibre.gui2.tweak_book.editor.smarts import NullSmarts
 from calibre.gui2.tweak_book.editor.smarts.utils import (
-    get_text_before_cursor, get_leading_whitespace_on_block as lw, no_modifiers,
+    get_text_before_cursor, get_leading_whitespace_on_block as lw,
-    test_modifiers, is_cursor_on_wrapped_line)
+    smart_home, smart_backspace, smart_tab)
 
 get_leading_whitespace_on_block = lambda editor, previous=False: expand_tabs(lw(editor, previous=previous))
 
@@ -35,29 +35,11 @@ class Smarts(NullSmarts):
     def handle_key_press(self, ev, editor):
         key = ev.key()
 
-        if key == Qt.Key_Tab:
+        if key == Qt.Key_Tab and smart_tab(editor, ev, tw):
-            cursor, text = get_text_before_cursor(editor)
-            if not text.lstrip():
-                # cursor is preceded by whitespace
-                text = expand_tabs(text)
-                spclen = len(text) - (len(text) % tw) + tw
-                cursor.insertText(' ' * spclen)
-                editor.setTextCursor(cursor)
-            else:
-                cursor = editor.textCursor()
-                cursor.insertText(' ' * tw)
-                editor.setTextCursor(cursor)
             return True
 
-        elif key == Qt.Key_Backspace:
+        elif key == Qt.Key_Backspace and smart_backspace(editor, ev, tw):
-            cursor, text = get_text_before_cursor(editor)
+            return True
-            if text and not text.lstrip():
-                # cursor is preceded by whitespace
-                text = expand_tabs(text)
-                spclen = max(0, len(text) - (len(text) % tw) - tw)
-                cursor.insertText(' ' * spclen)
-                editor.setTextCursor(cursor)
-                return True
 
         elif key in (Qt.Key_Enter, Qt.Key_Return):
             ls = get_leading_whitespace_on_block(editor)
@@ -83,15 +65,7 @@ class Smarts(NullSmarts):
                     editor.setTextCursor(cursor)
                     return True
 
-        elif key == Qt.Key_Home and no_modifiers(ev, Qt.ControlModifier) and not is_cursor_on_wrapped_line(editor):
+        if key == Qt.Key_Home and smart_home(editor, ev):
-            cursor, text = get_text_before_cursor(editor)
-            cursor = editor.textCursor()
-            mode = cursor.KeepAnchor if test_modifiers(ev, Qt.ShiftModifier) else cursor.MoveAnchor
-            cursor.movePosition(cursor.StartOfBlock, mode)
-            if text.strip():
-                # Move to the start of text
-                cursor.movePosition(cursor.NextWord, mode)
-            editor.setTextCursor(cursor)
             return True
 
 if __name__ == '__main__':

src/calibre/gui2/tweak_book/editor/smarts/utils.py

@@ -6,12 +6,16 @@ from __future__ import (unicode_literals, division, absolute_import,
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-def get_text_before_cursor(editor):
+from PyQt5.Qt import Qt
+
+def get_text_around_cursor(editor, before=True):
     cursor = editor.textCursor()
     cursor.clearSelection()
-    cursor.movePosition(cursor.StartOfBlock, cursor.KeepAnchor)
+    cursor.movePosition((cursor.StartOfBlock if before else cursor.EndOfBlock), cursor.KeepAnchor)
-    text = cursor.selectedText()
+    text = editor.selected_text_from_cursor(cursor)
     return cursor, text
+get_text_before_cursor = get_text_around_cursor
+get_text_after_cursor = lambda editor: get_text_around_cursor(editor, before=False)
 
 def is_cursor_on_wrapped_line(editor):
     cursor = editor.textCursor()
@@ -45,5 +49,41 @@ def test_modifiers(ev, *args):
             return False
     return True
 
+def smart_home(editor, ev):
+    if no_modifiers(ev, Qt.ControlModifier) and not is_cursor_on_wrapped_line(editor):
+        cursor, text = get_text_before_cursor(editor)
+        cursor = editor.textCursor()
+        mode = cursor.KeepAnchor if test_modifiers(ev, Qt.ShiftModifier) else cursor.MoveAnchor
+        cursor.movePosition(cursor.StartOfBlock, mode)
+        if text.strip():
+            # Move to the start of text
+            cursor.movePosition(cursor.NextWord, mode)
+        editor.setTextCursor(cursor)
+        return True
+    return False
 
+def expand_tabs(text, tw):
+    return text.replace('\t', ' ' * tw)
+
+def smart_tab(editor, ev, tw):
+    cursor, text = get_text_before_cursor(editor)
+    if not text.lstrip():
+        # cursor is preceded by only whitespace
+        text = expand_tabs(text, tw)
+        spclen = len(text) - (len(text) % tw) + tw
+        cursor.insertText(' ' * spclen)
+        editor.setTextCursor(cursor)
+        return True
+    return False
+
+def smart_backspace(editor, ev, tw):
+    cursor, text = get_text_before_cursor(editor)
+    if text and not text.lstrip():
+        # cursor is preceded by only whitespace
+        text = expand_tabs(text, tw)
+        spclen = max(0, len(text) - (len(text) % tw) - tw)
+        cursor.insertText(' ' * spclen)
+        editor.setTextCursor(cursor)
+        return True
+    return False