Implement open-with-offset

Resolves #60

babi/file.py

@@ -198,10 +198,12 @@ class File:
     def __init__(
             self,
             filename: Optional[str],
+            initial_line: int,
             color_manager: ColorManager,
             hl_factories: Tuple[HLFactory, ...],
     ) -> None:
         self.filename = filename
+        self.initial_line = initial_line
         self.modified = False
         self.buf = Buf([])
         self.nl = '\n'
@@ -215,7 +217,12 @@ class File:
         self.selection = Selection()
         self._file_hls: Tuple[FileHL, ...] = ()
 
-    def ensure_loaded(self, status: Status, stdin: str) -> None:
+    def ensure_loaded(
+            self,
+            status: Status,
+            margin: Margin,
+            stdin: str,
+    ) -> None:
         if self.buf:
             return
 
@@ -257,6 +264,8 @@ class File:
         for file_hl in self._file_hls:
             file_hl.register_callbacks(self.buf)
 
+        self.go_to_line(self.initial_line, margin)
+
     def __repr__(self) -> str:
         return f'<{type(self).__name__} {self.filename!r}>'
 

babi/main.py

@@ -1,9 +1,12 @@
 import argparse
 import curses
 import os
+import re
 import sys
+from typing import List
 from typing import Optional
 from typing import Sequence
+from typing import Tuple
 
 from babi.buf import Buf
 from babi.file import File
@@ -14,10 +17,11 @@ from babi.screen import make_stdscr
 from babi.screen import Screen
 
 CONSOLE = 'CONIN$' if sys.platform == 'win32' else '/dev/tty'
+POSITION_RE = re.compile(r'^\+-?\d+$')
 
 
 def _edit(screen: Screen, stdin: str) -> EditResult:
-    screen.file.ensure_loaded(screen.status, stdin)
+    screen.file.ensure_loaded(screen.status, screen.margin, stdin)
 
     while True:
         screen.status.tick(screen.margin)
@@ -40,11 +44,12 @@ def _edit(screen: Screen, stdin: str) -> EditResult:
 
 def c_main(
         stdscr: 'curses._CursesWindow',
-        args: argparse.Namespace,
+        filenames: List[Optional[str]],
+        positions: List[int],
         stdin: str,
+        perf: Perf,
 ) -> int:
-    with perf_log(args.perf_log) as perf:
-        screen = Screen(stdscr, args.filenames or [None], perf)
+    screen = Screen(stdscr, filenames, positions, perf)
     with screen.history.save():
         while screen.files:
             screen.i = screen.i % len(screen.files)
@@ -67,8 +72,8 @@ def c_main(
     return 0
 
 
-def _key_debug(stdscr: 'curses._CursesWindow') -> int:
-    screen = Screen(stdscr, ['<<key debug>>'], Perf())
+def _key_debug(stdscr: 'curses._CursesWindow', perf: Perf) -> int:
+    screen = Screen(stdscr, ['<<key debug>>'], [0], perf)
     screen.file.buf = Buf([''])
 
     while True:
@@ -85,6 +90,37 @@ def _key_debug(stdscr: 'curses._CursesWindow') -> int:
             return 0
 
 
+def _filenames(filenames: List[str]) -> Tuple[List[Optional[str]], List[int]]:
+    if not filenames:
+        return [None], [0]
+
+    ret_filenames: List[Optional[str]] = []
+    ret_positions = []
+
+    filenames_iter = iter(filenames)
+    for filename in filenames_iter:
+        if POSITION_RE.match(filename):
+            # in the success case we get:
+            #
+            # position_s = +...
+            # filename = (the next thing)
+            #
+            # in the error case we only need to reset `position_s` as
+            # `filename` is already correct
+            position_s = filename
+            try:
+                filename = next(filenames_iter)
+            except StopIteration:
+                position_s = '+0'
+            ret_positions.append(int(position_s[1:]))
+            ret_filenames.append(filename)
+        else:
+            ret_positions.append(0)
+            ret_filenames.append(filename)
+
+    return ret_filenames, ret_positions
+
+
 def main(argv: Optional[Sequence[str]] = None) -> int:
     parser = argparse.ArgumentParser()
     parser.add_argument('filenames', metavar='filename', nargs='*')
@@ -102,11 +138,12 @@ def main(argv: Optional[Sequence[str]] = None) -> int:
     else:
         stdin = ''
 
-    with make_stdscr() as stdscr:
+    with perf_log(args.perf_log) as perf, make_stdscr() as stdscr:
         if args.key_debug:
-            return _key_debug(stdscr)
+            return _key_debug(stdscr, perf)
         else:
-            return c_main(stdscr, args, stdin)
+            filenames, positions = _filenames(args.filenames)
+            return c_main(stdscr, filenames, positions, stdin, perf)
 
 
 if __name__ == '__main__':

babi/screen.py

@@ -103,14 +103,15 @@ class Screen:
             self,
             stdscr: 'curses._CursesWindow',
             filenames: List[Optional[str]],
+            initial_lines: List[int],
             perf: Perf,
     ) -> None:
         self.stdscr = stdscr
         self.color_manager = ColorManager.make()
         self.hl_factories = (Syntax.from_screen(stdscr, self.color_manager),)
         self.files = [
-            File(filename, self.color_manager, self.hl_factories)
-            for filename in filenames
+            File(filename, line, self.color_manager, self.hl_factories)
+            for filename, line in zip(filenames, initial_lines)
         ]
         self.i = 0
         self.history = History()
@@ -489,7 +490,7 @@ class Screen:
     def open_file(self) -> Optional[EditResult]:
         response = self.prompt('enter filename', history='open')
         if response is not PromptResult.CANCELLED:
-            opened = File(response, self.color_manager, self.hl_factories)
+            opened = File(response, 0, self.color_manager, self.hl_factories)
             self.files.append(opened)
             return EditResult.OPEN
         else:

tests/features/initial_position_test.py

@@ -0,0 +1,28 @@
+from testing.runner import and_exit
+
+
+def test_open_file_named_plus_something(run):
+    with run('+3') as h, and_exit(h):
+        h.await_text(' +3')
+
+
+def test_initial_position_one_file(run, tmpdir):
+    f = tmpdir.join('f')
+    f.write('hello\nworld\n')
+
+    with run('+2', str(f)) as h, and_exit(h):
+        h.await_cursor_position(x=0, y=2)
+
+
+def test_initial_position_multiple_files(run, tmpdir):
+    f = tmpdir.join('f')
+    f.write('1\n2\n3\n4\n')
+    g = tmpdir.join('g')
+    g.write('5\n6\n7\n8\n')
+
+    with run('+2', str(f), '+3', str(g)) as h, and_exit(h):
+        h.await_cursor_position(x=0, y=2)
+
+        h.press('^X')
+
+        h.await_cursor_position(x=0, y=3)

tests/file_test.py

@@ -8,7 +8,7 @@ from babi.file import get_lines
 
 
 def test_position_repr():
-    ret = repr(File('f.txt', ColorManager.make(), ()))
+    ret = repr(File('f.txt', 0, ColorManager.make(), ()))
     assert ret == "<File 'f.txt'>"
 
 

tests/main_test.py

@@ -0,0 +1,19 @@
+import pytest
+
+from babi import main
+
+
+@pytest.mark.parametrize(
+    ('in_filenames', 'expected_filenames', 'expected_positions'),
+    (
+        ([], [None], [0]),
+        (['+3'], ['+3'], [0]),
+        (['f'], ['f'], [0]),
+        (['+3', 'f'], ['f'], [3]),
+        (['+-3', 'f'], ['f'], [-3]),
+        (['+3', '+3'], ['+3'], [3]),
+        (['+2', 'f', '+5', 'g'], ['f', 'g'], [2, 5]),
+    ),
+)
+def test_filenames(in_filenames, expected_filenames, expected_positions):
+    filenames, positions = main._filenames(in_filenames)