Implement a command shell for kitty

Run it with:

kitty @

kitty/cli.py

@@ -288,6 +288,7 @@ def wrap(text, limit=80):
 
 def print_help_for_seq(seq, usage, message, appname):
     from kitty.icat import screen_size
+    screen_size.changed = True
     try:
         linesz = min(screen_size().cols, 76)
     except EnvironmentError:
@@ -337,7 +338,7 @@ def print_help_for_seq(seq, usage, message, appname):
             a('')
 
     text = '\n'.join(blocks) + '\n\n' + version()
-    if sys.stdout.isatty():
+    if print_help_for_seq.allow_pager and sys.stdout.isatty():
         p = subprocess.Popen(['less', '-isRXF'], stdin=subprocess.PIPE)
         p.communicate(text.encode('utf-8'))
         raise SystemExit(p.wait())
@@ -345,6 +346,9 @@ def print_help_for_seq(seq, usage, message, appname):
         print(text)
 
 
+print_help_for_seq.allow_pager = True
+
+
 def defval_for_opt(opt):
     dv = opt.get('default')
     typ = opt.get('type', '')

kitty/cmds.py

@@ -538,3 +538,10 @@ cmap = {v.name: v for v in globals().values() if hasattr(v, 'is_cmd')}
 def parse_subcommand_cli(func, args):
     opts, items = parse_args(args[1:], (func.options_spec or '\n').format, func.argspec, func.desc, '{} @ {}'.format(appname, func.name))
     return opts, items
+
+
+def display_subcommand_help(func):
+    try:
+        parse_args(['--help'], (func.options_spec or '\n').format, func.argspec, func.desc, func.name)
+    except SystemExit:
+        pass

kitty/remote_control.py

@@ -93,7 +93,9 @@ def main(args):
     global_opts, items = parse_args(args[1:], global_options_spec, 'command ...', msg, '{} @'.format(appname))
 
     if not items:
-        raise SystemExit('You must specify a command')
+        from kitty.shell import main
+        main(global_opts)
+        return
     cmd = items[0]
     try:
         func = cmap[cmd]

kitty/shell.py

@@ -0,0 +1,158 @@
+#!/usr/bin/env python
+# vim:fileencoding=utf-8
+# License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
+
+import os
+import readline
+import shlex
+import sys
+import traceback
+import types
+
+from .cli import emph, green, italic, print_help_for_seq, title
+from .cmds import cmap, display_subcommand_help, parse_subcommand_cli
+from .constants import cache_dir, version
+
+all_commands = tuple(sorted(cmap))
+
+
+class Completer:
+
+    def __init__(self):
+        self.matches = []
+        ddir = cache_dir()
+        try:
+            os.makedirs(ddir)
+        except FileExistsError:
+            pass
+        self.history_path = os.path.join(ddir, 'shell.history')
+
+    def complete(self, text, state):
+        response = None
+        return response
+
+    def __enter__(self):
+        if os.path.exists(self.history_path):
+            readline.read_history_file(self.history_path)
+        readline.set_completer(self.complete)
+        readline.parse_and_bind('tab: complete')
+        return self
+
+    def __exit__(self, *a):
+        readline.write_history_file(self.history_path)
+
+
+def print_err(*a, **kw):
+    kw['file'] = sys.stderr
+    print(*a, **kw)
+
+
+def print_help(which=None):
+    if which is None:
+        print('Control kitty by sending it commands.')
+        print()
+        print(title('Commands') + ':')
+        for cmd in all_commands:
+            c = cmap[cmd]
+            print(' ', green(c.name))
+            print('   ', c.short_desc)
+        print(' ', green('exit'))
+        print('   ', 'Exit this shell')
+        print('\nUse help {} for help on individual commands'.format(italic('command')))
+    else:
+        try:
+            func = cmap[which]
+        except KeyError:
+            if which == 'exit':
+                print('Exit this shell')
+            elif which == 'help':
+                print('Show help')
+            else:
+                print('Unknown command: {}'.format(emph(which)))
+            return
+        display_subcommand_help(func)
+
+
+def run_cmd(global_opts, cmd, func, opts, items):
+    from .remote_control import do_io
+    payload = func(global_opts, opts, items)
+    send = {
+        'cmd': cmd,
+        'version': version,
+    }
+    if func.no_response and isinstance(payload, types.GeneratorType):
+        for item in payload:
+            send['payload'] = item
+            do_io(global_opts.to, send, func.no_response)
+        return
+    if payload is not None:
+        send['payload'] = payload
+    response = do_io(global_opts.to, send, func.no_response)
+    if not response.get('ok'):
+        if response.get('tb'):
+            print_err(response['tb'])
+        print_err(response['error'])
+        return
+    if 'data' in response:
+        print(response['data'])
+
+
+def real_main(global_opts):
+    readline.read_init_file()
+    print_help_for_seq.allow_pager = False
+
+    while True:
+        try:
+            cmdline = input('🐱 ')
+        except EOFError:
+            break
+        except KeyboardInterrupt:
+            continue
+        if not cmdline:
+            continue
+        cmdline = shlex.split(cmdline)
+        cmd = cmdline[0].lower()
+
+        try:
+            func = cmap[cmd]
+        except KeyError:
+            if cmd in ('exit', 'quit'):
+                break
+            if cmd == 'help':
+                print_help(cmdline[1] if len(cmdline) > 1 else None)
+                continue
+            print_err('"{}" is an unknown command. Use "help" to see a list of commands.'.format(emph(cmd)))
+            continue
+
+        try:
+            opts, items = parse_subcommand_cli(func, cmdline)
+        except SystemExit as e:
+            if e.code != 0:
+                print_err(e)
+                print_err('Use "{}" to see how to use this command.'.format(emph('help ' + cmd)))
+            continue
+        except Exception:
+            print_err('Unhandled error:')
+            traceback.print_exc()
+            continue
+        else:
+            try:
+                run_cmd(global_opts, cmd, func, opts, items)
+            except SystemExit as e:
+                print_err(e)
+                continue
+            except KeyboardInterrupt:
+                continue
+            except Exception:
+                print_err('Unhandled error:')
+                traceback.print_exc()
+                continue
+
+
+def main(global_opts):
+    try:
+        real_main(global_opts)
+    except Exception:
+        traceback.print_exc()
+        input('Press enter to quit...')
+        raise SystemExit(1)