From 23d0367092c83b9fc179d6989919189ff6370187 Mon Sep 17 00:00:00 2001
From: Qexat <43090614+qexat@users.noreply.github.com>
Date: Sun, 17 Sep 2023 01:03:08 +0200
Subject: [PATCH 1/5] Add support for backword

---
 babi/file.py                        | 34 ++++++++++++++++++
 babi/screen.py                      |  1 +
 tests/features/conftest.py          |  2 ++
 tests/features/text_editing_test.py | 54 +++++++++++++++++++++++++++++
 4 files changed, 91 insertions(+)

diff --git a/babi/file.py b/babi/file.py
index 7a0d3531..8f0bac84 100644
--- a/babi/file.py
+++ b/babi/file.py
@@ -608,6 +608,39 @@ def backspace(self, dim: Dim) -> None:
             self.buf[self.buf.y] = s[:self.buf.x - 1] + s[self.buf.x:]
             self.buf.left(dim)
 
+    @edit_action('backword text', final=False)
+    @clear_selection
+    def backword(self, dim: Dim) -> None:
+        line = self.buf[self.buf.y]
+        if self.buf.x == 0 and self.buf.y == 0:
+            pass
+        elif self.buf.x == 0:
+            y, victim = self.buf.y, self.buf.pop(self.buf.y)
+            self.buf.left(dim)
+            self.buf[y - 1] += victim
+        elif self.buf.x > 0 and line[:self.buf.x].isspace():
+            while self.buf.x > 0:
+                s = self.buf[self.buf.y]
+                self.buf[self.buf.y] = s[:self.buf.x - 1] + s[self.buf.x:]
+                self.buf.left(dim)
+        else:
+            tp = line[self.buf.x - 1].isalnum()
+            # we keep track of whether we're deleting spaces
+            are_spaces = line[self.buf.x - 1].isspace()
+            while self.buf.x > 0 and tp == line[self.buf.x - 1].isalnum():
+                s = self.buf[self.buf.y]
+                self.buf[self.buf.y] = s[:self.buf.x - 1] + s[self.buf.x:]
+                self.buf.left(dim)
+
+            # if we were deleting spaces, this means we haven't deleted the
+            # word yet
+            tp = line[self.buf.x - 1].isalnum()
+            if are_spaces:
+                while self.buf.x > 0 and line[self.buf.x - 1].isalnum():
+                    s = self.buf[self.buf.y]
+                    self.buf[self.buf.y] = s[:self.buf.x - 1] + s[self.buf.x:]
+                    self.buf.left(dim)
+
     @edit_action('delete text', final=False)
     @clear_selection
     def delete(self, dim: Dim) -> None:
@@ -901,6 +934,7 @@ def reload(self, status: Status, dim: Dim) -> None:
         b'kDN3': alt_down,
         # editing
         b'KEY_BACKSPACE': backspace,
+        b'KEY_BACKWORD': backword,
         b'KEY_DC': delete,
         b'^M': enter,
         b'^I': tab,
diff --git a/babi/screen.py b/babi/screen.py
index e26c7026..00e35dd2 100644
--- a/babi/screen.py
+++ b/babi/screen.py
@@ -67,6 +67,7 @@
     '\x1b[1;6H': b'kHOM6',  # Shift + ^Home
     '\x1b[1;6F': b'kEND6',  # Shift + ^End
     '\x1b[~': b'KEY_BTAB',  # Shift + Tab
+    '\x1b(263)': b'KEY_BACKWORD',  # M-Backspace
 }
 KEYNAME_REWRITE = {
     # windows-curses: numeric pad arrow keys
diff --git a/tests/features/conftest.py b/tests/features/conftest.py
index d1b0851d..a1851b21 100644
--- a/tests/features/conftest.py
+++ b/tests/features/conftest.py
@@ -268,6 +268,8 @@ def value(self) -> int:
     Key('^End', b'kEND5', 530),
     Key('^S-Up', b'kUP6', 567),
     Key('^S-Down', b'kDN6', 526),
+    # 504 is backword but it doesn't work?
+    Key('M-BSpace', b'KEY_BACKWORD', 504),
     Key('M-Up', b'kUP3', 564),
     Key('M-Down', b'kDN3', 523),
     Key('M-Right', b'kRIT3', 558),
diff --git a/tests/features/text_editing_test.py b/tests/features/text_editing_test.py
index dd571df3..21de5635 100644
--- a/tests/features/text_editing_test.py
+++ b/tests/features/text_editing_test.py
@@ -79,6 +79,60 @@ def test_backspace_deletes_text(run, tmpdir, key):
         h.await_cursor_position(x=2, y=1)
 
 
+def test_backword_at_beginning_of_file(run):
+    # same behavior as backspace
+    with run() as h, and_exit(h):
+        h.press('M-BSpace')
+        h.await_text_missing('unknown key')
+        h.assert_cursor_line_equal('')
+        h.await_text_missing('*')
+
+
+def test_backword_joins_lines(run, tmpdir):
+    # same behavior as backspace
+    f = tmpdir.join('f')
+    f.write('foo\nbar\nbaz\n')
+
+    with run(str(f)) as h, and_exit(h):
+        h.await_text('foo')
+        h.press('Down')
+        h.press('M-BSpace')
+        h.await_text('foobar')
+        h.await_text('f *')
+        h.await_cursor_position(x=3, y=1)
+        # pressing down should retain the X position
+        h.press('Down')
+        h.await_cursor_position(x=3, y=2)
+
+
+def test_backword_deletes_text(run, tmpdir):
+    f = tmpdir.join('f')
+    f.write('ohai there')
+
+    with run(str(f)) as h, and_exit(h):
+        h.await_text('ohai there')
+        for _ in range(3):
+            h.press('Right')
+        h.press('M-BSpace')
+        h.await_text('i')
+        h.await_text('f *')
+        h.await_cursor_position(x=0, y=1)
+
+
+def test_backword_deletes_text_with_space_after(run, tmpdir):
+    f = tmpdir.join('f')
+    f.write('ohai there   ')
+
+    with run(str(f)) as h, and_exit(h):
+        h.await_text('ohai there')
+        for _ in range(13):
+            h.press('Right')
+        h.press('M-BSpace')
+        h.await_text('ohai')
+        h.await_text('f *')
+        h.await_cursor_position(x=5, y=1)
+
+
 def test_delete_at_end_of_file(run, tmpdir):
     with run() as h, and_exit(h):
         h.press('DC')

From 1c9919da28866c081a89c5539ff81684123a5dbf Mon Sep 17 00:00:00 2001
From: Qexat <43090614+qexat@users.noreply.github.com>
Date: Sun, 17 Sep 2023 01:04:31 +0200
Subject: [PATCH 2/5] Remove misleading comment

---
 tests/features/conftest.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/features/conftest.py b/tests/features/conftest.py
index a1851b21..a6e54e4d 100644
--- a/tests/features/conftest.py
+++ b/tests/features/conftest.py
@@ -268,7 +268,6 @@ def value(self) -> int:
     Key('^End', b'kEND5', 530),
     Key('^S-Up', b'kUP6', 567),
     Key('^S-Down', b'kDN6', 526),
-    # 504 is backword but it doesn't work?
     Key('M-BSpace', b'KEY_BACKWORD', 504),
     Key('M-Up', b'kUP3', 564),
     Key('M-Down', b'kDN3', 523),

From 71827244248315934d64df9532542b13a4152565 Mon Sep 17 00:00:00 2001
From: Qexat <43090614+qexat@users.noreply.github.com>
Date: Sat, 30 Sep 2023 20:56:21 +0200
Subject: [PATCH 3/5] Fix EOF behavior

---
 babi/file.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/babi/file.py b/babi/file.py
index 8f0bac84..fcf19014 100644
--- a/babi/file.py
+++ b/babi/file.py
@@ -614,6 +614,13 @@ def backword(self, dim: Dim) -> None:
         line = self.buf[self.buf.y]
         if self.buf.x == 0 and self.buf.y == 0:
             pass
+        # backword at the end of the file does not change the contents
+        elif (
+                self.buf.y == len(self.buf) - 1 and
+                # still allow backword if there are 2+ blank lines
+                self.buf[self.buf.y - 1] != ''
+        ):
+            self.buf.left(dim)
         elif self.buf.x == 0:
             y, victim = self.buf.y, self.buf.pop(self.buf.y)
             self.buf.left(dim)

From 3feb93a2ab47c71994f2255407edda925cdbe070 Mon Sep 17 00:00:00 2001
From: Qexat <43090614+qexat@users.noreply.github.com>
Date: Sat, 30 Sep 2023 21:11:31 +0200
Subject: [PATCH 4/5] an attempt to fix that test

---
 tests/features/movement_test.py     |  2 +-
 tests/features/text_editing_test.py | 25 +++++++++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/tests/features/movement_test.py b/tests/features/movement_test.py
index 84df1978..fa05b08e 100644
--- a/tests/features/movement_test.py
+++ b/tests/features/movement_test.py
@@ -412,7 +412,7 @@ def test_sequence_handling(run_only_fake):
         h.press('\x1b[1;')
         h.press(' test7')
         h.await_text('test1 test2 test3 test4 test5 test6 test7')
-        h.await_text(r'\x1b[1;')
+        h.await_text(r'\x1b(263)')
 
 
 def test_indentation_using_tabs(run, tmpdir):
diff --git a/tests/features/text_editing_test.py b/tests/features/text_editing_test.py
index 21de5635..1f336237 100644
--- a/tests/features/text_editing_test.py
+++ b/tests/features/text_editing_test.py
@@ -105,6 +105,31 @@ def test_backword_joins_lines(run, tmpdir):
         h.await_cursor_position(x=3, y=2)
 
 
+def test_backword_at_end_of_file_still_allows_scrolling_down(run, tmpdir):
+    f = tmpdir.join('f')
+    f.write('hello world')
+
+    with run(str(f)) as h, and_exit(h):
+        h.await_text('hello world')
+        h.press('Down')
+        h.press('M-BSpace')
+        h.press('Down')
+        h.await_cursor_position(x=0, y=2)
+        h.await_text_missing('*')
+
+
+def test_backword_deletes_newline_at_end_of_file(run, tmpdir):
+    f = tmpdir.join('f')
+    f.write('foo\n\n')
+
+    with run(str(f)) as h, and_exit(h):
+        h.press('^End')
+        h.press('M-BSpace')
+        h.press('^S')
+
+    assert f.read() == 'foo\n'
+
+
 def test_backword_deletes_text(run, tmpdir):
     f = tmpdir.join('f')
     f.write('ohai there')

From f29171936c72ffe62a0ac247f844aac745af6e31 Mon Sep 17 00:00:00 2001
From: Qexat <43090614+qexat@users.noreply.github.com>
Date: Sat, 30 Sep 2023 21:34:05 +0200
Subject: [PATCH 5/5] fix the fix because it was definitely wrong

---
 tests/features/movement_test.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/features/movement_test.py b/tests/features/movement_test.py
index fa05b08e..84df1978 100644
--- a/tests/features/movement_test.py
+++ b/tests/features/movement_test.py
@@ -412,7 +412,7 @@ def test_sequence_handling(run_only_fake):
         h.press('\x1b[1;')
         h.press(' test7')
         h.await_text('test1 test2 test3 test4 test5 test6 test7')
-        h.await_text(r'\x1b(263)')
+        h.await_text(r'\x1b[1;')
 
 
 def test_indentation_using_tabs(run, tmpdir):