Backport PR #10223: Fix error tab completing in the debugger

I think I broke this in 5.2.

Closes gh-10222

IPython/terminal/debugger.py

@@ -1,85 +1,88 b''
 from IPython.core.debugger import Pdb
 
 from IPython.core.completer import IPCompleter
 from .ptutils import IPythonPTCompleter
 
 from prompt_toolkit.token import Token
 from prompt_toolkit.shortcuts import create_prompt_application
 from prompt_toolkit.interface import CommandLineInterface
 from prompt_toolkit.enums import EditingMode
 import sys
 
 
 class TerminalPdb(Pdb):
     def __init__(self, *args, **kwargs):
         Pdb.__init__(self, *args, **kwargs)
         self._ptcomp = None
         self.pt_init()
 
     def pt_init(self):
         def get_prompt_tokens(cli):
             return [(Token.Prompt, self.prompt)]
 
+        def patch_stdout(**kwargs):
+            return self.pt_cli.patch_stdout_context(**kwargs)
+
         if self._ptcomp is None:
             compl = IPCompleter(shell=self.shell,
                                         namespace={},
                                         global_namespace={},
                                         use_readline=False,
                                         parent=self.shell,
                                        )
-            self._ptcomp = IPythonPTCompleter(compl)
+            self._ptcomp = IPythonPTCompleter(compl, patch_stdout=patch_stdout)
 
         self._pt_app = create_prompt_application(
                             editing_mode=getattr(EditingMode, self.shell.editing_mode.upper()),
                             history=self.shell.debugger_history,
                             completer= self._ptcomp,
                             enable_history_search=True,
                             mouse_support=self.shell.mouse_support,
                             get_prompt_tokens=get_prompt_tokens
         )
         self.pt_cli = CommandLineInterface(self._pt_app, eventloop=self.shell._eventloop)
 
     def cmdloop(self, intro=None):
         """Repeatedly issue a prompt, accept input, parse an initial prefix
         off the received input, and dispatch to action methods, passing them
         the remainder of the line as argument.
 
         override the same methods from cmd.Cmd to provide prompt toolkit replacement.
         """
         if not self.use_rawinput:
             raise ValueError('Sorry ipdb does not support use_rawinput=False')
 
         self.preloop()
 
         try:
             if intro is not None:
                 self.intro = intro
             if self.intro:
                 self.stdout.write(str(self.intro)+"\n")
             stop = None
             while not stop:
                 if self.cmdqueue:
                     line = self.cmdqueue.pop(0)
                 else:
                     self._ptcomp.ipy_completer.namespace = self.curframe_locals
                     self._ptcomp.ipy_completer.global_namespace = self.curframe.f_globals
                     try:
                         line = self.pt_cli.run(reset_current_buffer=True).text
                     except EOFError:
                         line = 'EOF'
                 line = self.precmd(line)
                 stop = self.onecmd(line)
                 stop = self.postcmd(stop, line)
             self.postloop()
         except Exception:
             raise
 
 
 def set_trace(frame=None):
     """
     Start debugging from `frame`.
 
     If frame is not specified, debugging starts from caller's frame.
     """
     TerminalPdb().set_trace(frame or sys._getframe().f_back)
 

IPython/terminal/interactiveshell.py

@@ -1,508 +1,512 b''
 """IPython terminal interface using prompt_toolkit"""
 from __future__ import print_function
 
 import os
 import sys
 import warnings
 from warnings import warn
 
 from IPython.core.interactiveshell import InteractiveShell, InteractiveShellABC
 from IPython.utils import io
 from IPython.utils.py3compat import PY3, cast_unicode_py2, input, string_types
 from IPython.utils.terminal import toggle_set_term_title, set_term_title
 from IPython.utils.process import abbrev_cwd
 from traitlets import Bool, Unicode, Dict, Integer, observe, Instance, Type, default, Enum, Union
 
 from prompt_toolkit.enums import DEFAULT_BUFFER, EditingMode
 from prompt_toolkit.filters import (HasFocus, Condition, IsDone)
 from prompt_toolkit.history import InMemoryHistory
 from prompt_toolkit.shortcuts import create_prompt_application, create_eventloop, create_prompt_layout, create_output
 from prompt_toolkit.interface import CommandLineInterface
 from prompt_toolkit.key_binding.manager import KeyBindingManager
 from prompt_toolkit.layout.processors import ConditionalProcessor, HighlightMatchingBracketProcessor
 from prompt_toolkit.styles import PygmentsStyle, DynamicStyle
 
 from pygments.styles import get_style_by_name, get_all_styles
 from pygments.style import Style
 from pygments.token import Token
 
 from .debugger import TerminalPdb, Pdb
 from .magics import TerminalMagics
 from .pt_inputhooks import get_inputhook_name_and_func
 from .prompts import Prompts, ClassicPrompts, RichPromptDisplayHook
 from .ptutils import IPythonPTCompleter, IPythonPTLexer
 from .shortcuts import register_ipython_shortcuts
 
 DISPLAY_BANNER_DEPRECATED = object()
 
 
 from pygments.style import Style
 
 class _NoStyle(Style): pass
 
 
 
 _style_overrides_light_bg = {
             Token.Prompt: '#0000ff',
             Token.PromptNum: '#0000ee bold',
             Token.OutPrompt: '#cc0000',
             Token.OutPromptNum: '#bb0000 bold',
 }
 
 _style_overrides_linux = {
             Token.Prompt: '#00cc00',
             Token.PromptNum: '#00bb00 bold',
             Token.OutPrompt: '#cc0000',
             Token.OutPromptNum: '#bb0000 bold',
 }
 
 
 
 def get_default_editor():
     try:
         ed = os.environ['EDITOR']
         if not PY3:
             ed = ed.decode()
         return ed
     except KeyError:
         pass
     except UnicodeError:
         warn("$EDITOR environment variable is not pure ASCII. Using platform "
              "default editor.")
 
     if os.name == 'posix':
         return 'vi'  # the only one guaranteed to be there!
     else:
         return 'notepad' # same in Windows!
 
 # conservatively check for tty
 # overridden streams can result in things like:
 # - sys.stdin = None
 # - no isatty method
 for _name in ('stdin', 'stdout', 'stderr'):
     _stream = getattr(sys, _name)
     if not _stream or not hasattr(_stream, 'isatty') or not _stream.isatty():
         _is_tty = False
         break
 else:
     _is_tty = True
 
 
 _use_simple_prompt = ('IPY_TEST_SIMPLE_PROMPT' in os.environ) or (not _is_tty)
 
 class TerminalInteractiveShell(InteractiveShell):
     space_for_menu = Integer(6, help='Number of line at the bottom of the screen '
                                                   'to reserve for the completion menu'
                             ).tag(config=True)
 
     def _space_for_menu_changed(self, old, new):
         self._update_layout()
 
     pt_cli = None
     debugger_history = None
     _pt_app = None
 
     simple_prompt = Bool(_use_simple_prompt,
         help="""Use `raw_input` for the REPL, without completion, multiline input, and prompt colors.
 
             Useful when controlling IPython as a subprocess, and piping STDIN/OUT/ERR. Known usage are:
             IPython own testing machinery, and emacs inferior-shell integration through elpy.
 
             This mode default to `True` if the `IPY_TEST_SIMPLE_PROMPT`
             environment variable is set, or the current terminal is not a tty.
 
             """
             ).tag(config=True)
 
     @property
     def debugger_cls(self):
         return Pdb if self.simple_prompt else TerminalPdb
 
     confirm_exit = Bool(True,
         help="""
         Set to confirm when you try to exit IPython with an EOF (Control-D
         in Unix, Control-Z/Enter in Windows). By typing 'exit' or 'quit',
         you can force a direct exit without any confirmation.""",
     ).tag(config=True)
 
     editing_mode = Unicode('emacs',
         help="Shortcut style to use at the prompt. 'vi' or 'emacs'.",
     ).tag(config=True)
 
     mouse_support = Bool(False,
         help="Enable mouse support in the prompt"
     ).tag(config=True)
 
     highlighting_style = Union([Unicode('legacy'), Type(klass=Style)],
         help="""The name or class of a Pygments style to use for syntax
         highlighting: \n %s""" % ', '.join(get_all_styles())
     ).tag(config=True)
 
 
     @observe('highlighting_style')
     @observe('colors')
     def _highlighting_style_changed(self, change):
         self.refresh_style()
 
     def refresh_style(self):
         self._style = self._make_style_from_name_or_cls(self.highlighting_style)
 
 
     highlighting_style_overrides = Dict(
         help="Override highlighting format for specific tokens"
     ).tag(config=True)
 
     true_color = Bool(False,
         help=("Use 24bit colors instead of 256 colors in prompt highlighting. "
               "If your terminal supports true color, the following command "
               "should print 'TRUECOLOR' in orange: "
               "printf \"\\x1b[38;2;255;100;0mTRUECOLOR\\x1b[0m\\n\"")
     ).tag(config=True)
 
     editor = Unicode(get_default_editor(),
         help="Set the editor used by IPython (default to $EDITOR/vi/notepad)."
     ).tag(config=True)
 
     prompts_class = Type(Prompts, help='Class used to generate Prompt token for prompt_toolkit').tag(config=True)
 
     prompts = Instance(Prompts)
 
     @default('prompts')
     def _prompts_default(self):
         return self.prompts_class(self)
 
     @observe('prompts')
     def _(self, change):
         self._update_layout()
 
     @default('displayhook_class')
     def _displayhook_class_default(self):
         return RichPromptDisplayHook
 
     term_title = Bool(True,
         help="Automatically set the terminal title"
     ).tag(config=True)
 
     display_completions = Enum(('column', 'multicolumn','readlinelike'),
         help= ( "Options for displaying tab completions, 'column', 'multicolumn', and "
                 "'readlinelike'. These options are for `prompt_toolkit`, see "
                 "`prompt_toolkit` documentation for more information."
                 ),
         default_value='multicolumn').tag(config=True)
 
     highlight_matching_brackets = Bool(True,
         help="Highlight matching brackets .",
     ).tag(config=True)
 
     @observe('term_title')
     def init_term_title(self, change=None):
         # Enable or disable the terminal title.
         if self.term_title:
             toggle_set_term_title(True)
             set_term_title('IPython: ' + abbrev_cwd())
         else:
             toggle_set_term_title(False)
 
     def init_display_formatter(self):
         super(TerminalInteractiveShell, self).init_display_formatter()
         # terminal only supports plain text
         self.display_formatter.active_types = ['text/plain']
 
     def init_prompt_toolkit_cli(self):
         if self.simple_prompt:
             # Fall back to plain non-interactive output for tests.
             # This is very limited, and only accepts a single line.
             def prompt():
                 return cast_unicode_py2(input('In [%d]: ' % self.execution_count))
             self.prompt_for_code = prompt
             return
 
         # Set up keyboard shortcuts
         kbmanager = KeyBindingManager.for_prompt()
         register_ipython_shortcuts(kbmanager.registry, self)
 
         # Pre-populate history from IPython's history database
         history = InMemoryHistory()
         last_cell = u""
         for __, ___, cell in self.history_manager.get_tail(self.history_load_length,
                                                         include_latest=True):
             # Ignore blank lines and consecutive duplicates
             cell = cell.rstrip()
             if cell and (cell != last_cell):
                 history.append(cell)
                 last_cell = cell
 
         self._style = self._make_style_from_name_or_cls(self.highlighting_style)
         style = DynamicStyle(lambda: self._style)
 
         editing_mode = getattr(EditingMode, self.editing_mode.upper())
 
+        def patch_stdout(**kwargs):
+            return self.pt_cli.patch_stdout_context(**kwargs)
+
         self._pt_app = create_prompt_application(
                             editing_mode=editing_mode,
                             key_bindings_registry=kbmanager.registry,
                             history=history,
-                            completer=IPythonPTCompleter(shell=self),
+                            completer=IPythonPTCompleter(shell=self,
+                                                    patch_stdout=patch_stdout),
                             enable_history_search=True,
                             style=style,
                             mouse_support=self.mouse_support,
                             **self._layout_options()
         )
         self._eventloop = create_eventloop(self.inputhook)
         self.pt_cli = CommandLineInterface(
             self._pt_app, eventloop=self._eventloop,
             output=create_output(true_color=self.true_color))
 
     def _make_style_from_name_or_cls(self, name_or_cls):
         """
         Small wrapper that make an IPython compatible style from a style name
 
         We need that to add style for prompt ... etc.
         """
         style_overrides = {}
         if name_or_cls == 'legacy':
             legacy = self.colors.lower()
             if legacy == 'linux':
                 style_cls = get_style_by_name('monokai')
                 style_overrides = _style_overrides_linux
             elif legacy == 'lightbg':
                 style_overrides = _style_overrides_light_bg
                 style_cls = get_style_by_name('pastie')
             elif legacy == 'neutral':
                 # The default theme needs to be visible on both a dark background
                 # and a light background, because we can't tell what the terminal
                 # looks like. These tweaks to the default theme help with that.
                 style_cls = get_style_by_name('default')
                 style_overrides.update({
                     Token.Number: '#007700',
                     Token.Operator: 'noinherit',
                     Token.String: '#BB6622',
                     Token.Name.Function: '#2080D0',
                     Token.Name.Class: 'bold #2080D0',
                     Token.Name.Namespace: 'bold #2080D0',
                     Token.Prompt: '#009900',
                     Token.PromptNum: '#00ff00 bold',
                     Token.OutPrompt: '#990000',
                     Token.OutPromptNum: '#ff0000 bold',
                 })
             elif legacy =='nocolor':
                 style_cls=_NoStyle
                 style_overrides = {}
             else :
                 raise ValueError('Got unknown colors: ', legacy)
         else :
             if isinstance(name_or_cls, string_types):
                 style_cls = get_style_by_name(name_or_cls)
             else:
                 style_cls = name_or_cls
             style_overrides = {
                 Token.Prompt: '#009900',
                 Token.PromptNum: '#00ff00 bold',
                 Token.OutPrompt: '#990000',
                 Token.OutPromptNum: '#ff0000 bold',
             }
         style_overrides.update(self.highlighting_style_overrides)
         style = PygmentsStyle.from_defaults(pygments_style_cls=style_cls,
                                             style_dict=style_overrides)
 
         return style
 
     def _layout_options(self):
         """
         Return the current layout option for the current Terminal InteractiveShell
         """
         return {
                 'lexer':IPythonPTLexer(),
                 'reserve_space_for_menu':self.space_for_menu,
                 'get_prompt_tokens':self.prompts.in_prompt_tokens,
                 'get_continuation_tokens':self.prompts.continuation_prompt_tokens,
                 'multiline':True,
                 'display_completions_in_columns': (self.display_completions == 'multicolumn'),
 
                 # Highlight matching brackets, but only when this setting is
                 # enabled, and only when the DEFAULT_BUFFER has the focus.
                 'extra_input_processors': [ConditionalProcessor(
                         processor=HighlightMatchingBracketProcessor(chars='[](){}'),
                         filter=HasFocus(DEFAULT_BUFFER) & ~IsDone() &
                             Condition(lambda cli: self.highlight_matching_brackets))],
                 }
 
     def _update_layout(self):
         """
         Ask for a re computation of the application layout, if for example ,
         some configuration options have changed.
         """
         if self._pt_app:
             self._pt_app.layout = create_prompt_layout(**self._layout_options())
 
     def prompt_for_code(self):
         document = self.pt_cli.run(
             pre_run=self.pre_prompt, reset_current_buffer=True)
         return document.text
 
     def enable_win_unicode_console(self):
         if sys.version_info >= (3, 6):
             # Since PEP 528, Python uses the unicode APIs for the Windows
             # console by default, so WUC shouldn't be needed.
             return
 
         import win_unicode_console
 
         if PY3:
             win_unicode_console.enable()
         else:
             # https://github.com/ipython/ipython/issues/9768
             from win_unicode_console.streams import (TextStreamWrapper,
                                  stdout_text_transcoded, stderr_text_transcoded)
 
             class LenientStrStreamWrapper(TextStreamWrapper):
                 def write(self, s):
                     if isinstance(s, bytes):
                         s = s.decode(self.encoding, 'replace')
 
                     self.base.write(s)
 
             stdout_text_str = LenientStrStreamWrapper(stdout_text_transcoded)
             stderr_text_str = LenientStrStreamWrapper(stderr_text_transcoded)
 
             win_unicode_console.enable(stdout=stdout_text_str,
                                        stderr=stderr_text_str)
 
     def init_io(self):
         if sys.platform not in {'win32', 'cli'}:
             return
 
         self.enable_win_unicode_console()
 
         import colorama
         colorama.init()
 
         # For some reason we make these wrappers around stdout/stderr.
         # For now, we need to reset them so all output gets coloured.
         # https://github.com/ipython/ipython/issues/8669
         # io.std* are deprecated, but don't show our own deprecation warnings
         # during initialization of the deprecated API.
         with warnings.catch_warnings():
             warnings.simplefilter('ignore', DeprecationWarning)
             io.stdout = io.IOStream(sys.stdout)
             io.stderr = io.IOStream(sys.stderr)
 
     def init_magics(self):
         super(TerminalInteractiveShell, self).init_magics()
         self.register_magics(TerminalMagics)
 
     def init_alias(self):
         # The parent class defines aliases that can be safely used with any
         # frontend.
         super(TerminalInteractiveShell, self).init_alias()
 
         # Now define aliases that only make sense on the terminal, because they
         # need direct access to the console in a way that we can't emulate in
         # GUI or web frontend
         if os.name == 'posix':
             for cmd in ['clear', 'more', 'less', 'man']:
                 self.alias_manager.soft_define_alias(cmd, cmd)
 
 
     def __init__(self, *args, **kwargs):
         super(TerminalInteractiveShell, self).__init__(*args, **kwargs)
         self.init_prompt_toolkit_cli()
         self.init_term_title()
         self.keep_running = True
 
         self.debugger_history = InMemoryHistory()
 
     def ask_exit(self):
         self.keep_running = False
 
     rl_next_input = None
 
     def pre_prompt(self):
         if self.rl_next_input:
             self.pt_cli.application.buffer.text = cast_unicode_py2(self.rl_next_input)
             self.rl_next_input = None
 
     def interact(self, display_banner=DISPLAY_BANNER_DEPRECATED):
 
         if display_banner is not DISPLAY_BANNER_DEPRECATED:
             warn('interact `display_banner` argument is deprecated since IPython 5.0. Call `show_banner()` if needed.', DeprecationWarning, stacklevel=2)
 
         self.keep_running = True
         while self.keep_running:
             print(self.separate_in, end='')
 
             try:
                 code = self.prompt_for_code()
             except EOFError:
                 if (not self.confirm_exit) \
                         or self.ask_yes_no('Do you really want to exit ([y]/n)?','y','n'):
                     self.ask_exit()
 
             else:
                 if code:
                     self.run_cell(code, store_history=True)
 
     def mainloop(self, display_banner=DISPLAY_BANNER_DEPRECATED):
         # An extra layer of protection in case someone mashing Ctrl-C breaks
         # out of our internal code.
         if display_banner is not DISPLAY_BANNER_DEPRECATED:
             warn('mainloop `display_banner` argument is deprecated since IPython 5.0. Call `show_banner()` if needed.', DeprecationWarning, stacklevel=2)
         while True:
             try:
                 self.interact()
                 break
             except KeyboardInterrupt as e:
                 print("\n%s escaped interact()\n" % type(e).__name__)
             finally:
                 # An interrupt during the eventloop will mess up the
                 # internal state of the prompt_toolkit library.
                 # Stopping the eventloop fixes this, see
                 # https://github.com/ipython/ipython/pull/9867
                 if hasattr(self, '_eventloop'):
                     self._eventloop.stop()
 
     _inputhook = None
     def inputhook(self, context):
         if self._inputhook is not None:
             self._inputhook(context)
 
     active_eventloop = None
     def enable_gui(self, gui=None):
         if gui:
             self.active_eventloop, self._inputhook =\
                 get_inputhook_name_and_func(gui)
         else:
             self.active_eventloop = self._inputhook = None
 
     # Run !system commands directly, not through pipes, so terminal programs
     # work correctly.
     system = InteractiveShell.system_raw
 
     def auto_rewrite_input(self, cmd):
         """Overridden from the parent class to use fancy rewriting prompt"""
         if not self.show_rewritten_input:
             return
 
         tokens = self.prompts.rewrite_prompt_tokens()
         if self.pt_cli:
             self.pt_cli.print_tokens(tokens)
             print(cmd)
         else:
             prompt = ''.join(s for t, s in tokens)
             print(prompt, cmd, sep='')
 
     _prompts_before = None
     def switch_doctest_mode(self, mode):
         """Switch prompts to classic for %doctest_mode"""
         if mode:
             self._prompts_before = self.prompts
             self.prompts = ClassicPrompts(self)
         elif self._prompts_before:
             self.prompts = self._prompts_before
             self._prompts_before = None
         self._update_layout()
 
 
 InteractiveShellABC.register(TerminalInteractiveShell)
 
 if __name__ == '__main__':
     TerminalInteractiveShell.instance().interact()

IPython/terminal/ptutils.py

@@ -1,112 +1,115 b''
 """prompt-toolkit utilities
 
 Everything in this module is a private API,
 not to be used outside IPython.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import unicodedata
 from wcwidth import wcwidth
 
 from IPython.utils.py3compat import PY3
 
 from IPython.core.completer import IPCompleter
 from prompt_toolkit.completion import Completer, Completion
 from prompt_toolkit.layout.lexers import Lexer
 from prompt_toolkit.layout.lexers import PygmentsLexer
 
 import pygments.lexers as pygments_lexers
 
 
 class IPythonPTCompleter(Completer):
     """Adaptor to provide IPython completions to prompt_toolkit"""
-    def __init__(self, ipy_completer=None, shell=None):
+    def __init__(self, ipy_completer=None, shell=None, patch_stdout=None):
         if shell is None and ipy_completer is None:
             raise TypeError("Please pass shell=an InteractiveShell instance.")
         self._ipy_completer = ipy_completer
         self.shell = shell
+        if patch_stdout is None:
+            raise TypeError("Please pass patch_stdout")
+        self.patch_stdout = patch_stdout
 
     @property
     def ipy_completer(self):
         if self._ipy_completer:
             return self._ipy_completer
         else:
             return self.shell.Completer
 
     def get_completions(self, document, complete_event):
         if not document.current_line.strip():
             return
 
         # Some bits of our completion system may print stuff (e.g. if a module
         # is imported). This context manager ensures that doesn't interfere with
         # the prompt.
-        with self.shell.pt_cli.patch_stdout_context():
+        with self.patch_stdout():
             used, matches = self.ipy_completer.complete(
                                 line_buffer=document.current_line,
                                 cursor_pos=document.cursor_position_col
             )
         start_pos = -len(used)
         for m in matches:
             if not m:
                 # Guard against completion machinery giving us an empty string.
                 continue
 
             m = unicodedata.normalize('NFC', m)
 
             # When the first character of the completion has a zero length,
             # then it's probably a decomposed unicode character. E.g. caused by
             # the "\dot" completion. Try to compose again with the previous
             # character.
             if wcwidth(m[0]) == 0:
                 if document.cursor_position + start_pos > 0:
                     char_before = document.text[document.cursor_position + start_pos - 1]
                     m = unicodedata.normalize('NFC', char_before + m)
 
                     # Yield the modified completion instead, if this worked.
                     if wcwidth(m[0:1]) == 1:
                         yield Completion(m, start_position=start_pos - 1)
                         continue
 
             # TODO: Use Jedi to determine meta_text
             # (Jedi currently has a bug that results in incorrect information.)
             # meta_text = ''
             # yield Completion(m, start_position=start_pos,
             #                  display_meta=meta_text)
             yield Completion(m, start_position=start_pos)
 
 class IPythonPTLexer(Lexer):
     """
     Wrapper around PythonLexer and BashLexer.
     """
     def __init__(self):
         l = pygments_lexers
         self.python_lexer = PygmentsLexer(l.Python3Lexer if PY3 else l.PythonLexer)
         self.shell_lexer = PygmentsLexer(l.BashLexer)
 
         self.magic_lexers = {
             'HTML': PygmentsLexer(l.HtmlLexer),
             'html': PygmentsLexer(l.HtmlLexer),
             'javascript': PygmentsLexer(l.JavascriptLexer),
             'js': PygmentsLexer(l.JavascriptLexer),
             'perl': PygmentsLexer(l.PerlLexer),
             'ruby': PygmentsLexer(l.RubyLexer),
             'latex': PygmentsLexer(l.TexLexer),
         }
 
     def lex_document(self, cli, document):
         text = document.text.lstrip()
 
         lexer = self.python_lexer
 
         if text.startswith('!') or text.startswith('%%bash'):
             lexer = self.shell_lexer
 
         elif text.startswith('%%'):
             for magic, l in self.magic_lexers.items():
                 if text.startswith('%%' + magic):
                     lexer = l
                     break
 
         return lexer.lex_document(cli, document)