Add :tabsize and :tabstop

babi/buf.py

@@ -19,11 +19,11 @@ DelCallback = Callable[['Buf', int, str], None]
 InsCallback = Callable[['Buf', int], None]
 
 
-def _offsets(s: str) -> Tuple[int, ...]:
+def _offsets(s: str, tab_size: int) -> Tuple[int, ...]:
     ret = [0]
     for c in s:
         if c == '\t':
-            ret.append(ret[-1] + (4 - ret[-1] % 4))
+            ret.append(ret[-1] + (tab_size - ret[-1] % tab_size))
         else:
             ret.append(ret[-1] + wcwidth(c))
     return tuple(ret)
@@ -57,8 +57,9 @@ class DelModification(NamedTuple):
 
 
 class Buf:
-    def __init__(self, lines: List[str]) -> None:
+    def __init__(self, lines: List[str], tab_size: int = 4) -> None:
         self._lines = lines
+        self.tab_size = tab_size
         self.file_y = self.y = self._x = self._x_hint = 0
 
         self._set_callbacks: List[SetCallback] = [self._set_cb]
@@ -136,6 +137,10 @@ class Buf:
         if self[-1] != '':
             self.append('')
 
+    def set_tab_size(self, tab_size: int) -> None:
+        self.tab_size = tab_size
+        self._positions = [None]
+
     # event handling
 
     def add_set_callback(self, cb: SetCallback) -> None:
@@ -219,7 +224,8 @@ class Buf:
         self._extend_positions(idx)
         value = self._positions[idx]
         if value is None:
-            value = self._positions[idx] = _offsets(self._lines[idx])
+            value = _offsets(self._lines[idx], self.tab_size)
+            self._positions[idx] = value
         return value
 
     def line_x(self, margin: Margin) -> int:
@@ -238,7 +244,8 @@ class Buf:
 
     def rendered_line(self, idx: int, margin: Margin) -> str:
         x = self._cursor_x if idx == self.y else 0
-        return scrolled_line(self._lines[idx].expandtabs(4), x, margin.cols)
+        expanded = self._lines[idx].expandtabs(self.tab_size)
+        return scrolled_line(expanded, x, margin.cols)
 
     # movement
 

babi/file.py

@@ -244,7 +244,7 @@ class File:
                     status.update('(new file)')
             lines, self.nl, mixed, self.sha256 = get_lines(io.StringIO(''))
 
-        self.buf = Buf(lines)
+        self.buf = Buf(lines, self.buf.tab_size)
 
         if mixed:
             status.update(f'mixed newlines will be converted to {self.nl!r}')
@@ -523,16 +523,16 @@ class File:
         (s_y, _), (e_y, _) = self.selection.get()
         for l_y in range(s_y, e_y + 1):
             if self.buf[l_y]:
-                self.buf[l_y] = ' ' * 4 + self.buf[l_y]
+                self.buf[l_y] = ' ' * self.buf.tab_size + self.buf[l_y]
                 if l_y == self.buf.y:
-                    self.buf.x += 4
+                    self.buf.x += self.buf.tab_size
                 if l_y == sel_y and sel_x != 0:
-                    sel_x += 4
+                    sel_x += self.buf.tab_size
         self.selection.set(sel_y, sel_x, self.buf.y, self.buf.x)
 
     @edit_action('insert tab', final=False)
     def _tab(self, margin: Margin) -> None:
-        n = 4 - self.buf.x % 4
+        n = self.buf.tab_size - self.buf.x % self.buf.tab_size
         line = self.buf[self.buf.y]
         self.buf[self.buf.y] = line[:self.buf.x] + n * ' ' + line[self.buf.x:]
         self.buf.x += n
@@ -544,9 +544,8 @@ class File:
         else:
             self._tab(margin)
 
-    @staticmethod
-    def _dedent_line(s: str) -> int:
-        bound = min(len(s), 4)
+    def _dedent_line(self, s: str) -> int:
+        bound = min(len(s), self.buf.tab_size)
         i = 0
         while i < bound and s[i] == ' ':
             i += 1

babi/screen.py

@@ -421,7 +421,9 @@ class Screen:
 
     def command(self) -> Optional[EditResult]:
         response = self.prompt('', history='command')
-        if response == ':q':
+        if response is PromptResult.CANCELLED:
+            pass
+        elif response == ':q':
             return self.quit_save_modified()
         elif response == ':q!':
             return EditResult.EXIT
@@ -442,7 +444,20 @@ class Screen:
             else:
                 self.file.sort(self.margin, reverse=True)
             self.status.update('sorted!')
-        elif response is not PromptResult.CANCELLED:
+        elif response.startswith((':tabstop ', ':tabsize ')):
+            _, _, tab_size = response.partition(' ')
+            try:
+                parsed_tab_size = int(tab_size)
+            except ValueError:
+                self.status.update(f'invalid size: {tab_size}')
+            else:
+                if parsed_tab_size <= 0:
+                    self.status.update(f'invalid size: {parsed_tab_size}')
+                else:
+                    for file in self.files:
+                        file.buf.set_tab_size(parsed_tab_size)
+                    self.status.update('updated!')
+        else:
             self.status.update(f'invalid command: {response}')
         return None
 

tests/features/tabsize_test.py

@@ -0,0 +1,30 @@
+import pytest
+
+from testing.runner import and_exit
+from testing.runner import trigger_command_mode
+
+
+@pytest.mark.parametrize('setting', ('tabsize', 'tabstop'))
+def test_set_tabstop(run, setting):
+    with run() as h, and_exit(h):
+        h.press('a')
+        h.press('Left')
+        trigger_command_mode(h)
+        h.press_and_enter(f':{setting} 2')
+        h.await_text('updated!')
+        h.press('Tab')
+        h.await_text('\n  a')
+        h.await_cursor_position(x=2, y=1)
+
+
+@pytest.mark.parametrize('tabsize', ('-1', '0', 'wat'))
+def test_set_invalid_tabstop(run, tabsize):
+    with run() as h, and_exit(h):
+        h.press('a')
+        h.press('Left')
+        trigger_command_mode(h)
+        h.press_and_enter(f':tabstop {tabsize}')
+        h.await_text(f'invalid size: {tabsize}')
+        h.press('Tab')
+        h.await_text('    a')
+        h.await_cursor_position(x=4, y=1)