Merging upstream version 3.0.19.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

10 files changed, 242 insertions, 188 deletions

diff --git a/ptpython/completer.py b/ptpython/completer.py
index 9f7e10b..285398c 100644
--- a/ptpython/completer.py
+++ b/ptpython/completer.py
@@ -468,7 +468,7 @@ class DictionaryCompleter(Completer):
         """
 
         def abbr_meta(text: str) -> str:
-            " Abbreviate meta text, make sure it fits on one line. "
+            "Abbreviate meta text, make sure it fits on one line."
             # Take first line, if multiple lines.
             if len(text) > 20:
                 text = text[:20] + "..."
@@ -621,7 +621,7 @@ class HidePrivateCompleter(Completer):
 
 
 class ReprFailedError(Exception):
-    " Raised when the repr() call in `DictionaryCompleter` fails. "
+    "Raised when the repr() call in `DictionaryCompleter` fails."
 
 
 try:
diff --git a/ptpython/entry_points/run_ptipython.py b/ptpython/entry_points/run_ptipython.py
index 650633e..21d7063 100644
--- a/ptpython/entry_points/run_ptipython.py
+++ b/ptpython/entry_points/run_ptipython.py
@@ -31,7 +31,7 @@ def run(user_ns=None):
         path = a.args[0]
         with open(path, "rb") as f:
             code = compile(f.read(), path, "exec")
-            exec(code, {})
+            exec(code, {"__name__": "__main__", "__file__": path})
     else:
         enable_deprecation_warnings()
 
diff --git a/ptpython/entry_points/run_ptpython.py b/ptpython/entry_points/run_ptpython.py
index 0b3dbdb..5ebe2b9 100644
--- a/ptpython/entry_points/run_ptpython.py
+++ b/ptpython/entry_points/run_ptpython.py
@@ -179,9 +179,11 @@ def run() -> None:
         path = a.args[0]
         with open(path, "rb") as f:
             code = compile(f.read(), path, "exec")
-            # NOTE: We have to pass an empty dictionary as namespace. Omitting
-            #       this argument causes imports to not be found. See issue #326.
-            exec(code, {})
+            # NOTE: We have to pass a dict as namespace. Omitting this argument
+            #       causes imports to not be found. See issue #326.
+            #       However, an empty dict sets __name__ to 'builtins', which
+            #       breaks `if __name__ == '__main__'` checks. See issue #444.
+            exec(code, {"__name__": "__main__", "__file__": path})
 
     # Run interactive shell.
     else:
diff --git a/ptpython/history_browser.py b/ptpython/history_browser.py
index 798a280..b7fe086 100644
--- a/ptpython/history_browser.py
+++ b/ptpython/history_browser.py
@@ -85,7 +85,7 @@ Further, remember that searching works like in Emacs
 
 
 class BORDER:
-    " Box drawing characters. "
+    "Box drawing characters."
     HORIZONTAL = "\u2501"
     VERTICAL = "\u2503"
     TOP_LEFT = "\u250f"
@@ -420,7 +420,7 @@ class HistoryMapping:
 
 
 def _toggle_help(history):
-    " Display/hide help. "
+    "Display/hide help."
     help_buffer_control = history.history_layout.help_buffer_control
 
     if history.app.layout.current_control == help_buffer_control:
@@ -430,7 +430,7 @@ def _toggle_help(history):
 
 
 def _select_other_window(history):
-    " Toggle focus between left/right window. "
+    "Toggle focus between left/right window."
     current_buffer = history.app.current_buffer
     layout = history.history_layout.layout
 
@@ -513,17 +513,17 @@ def create_key_bindings(history, python_input, history_mapping):
     # Eager: ignore the Emacs [Ctrl-X Ctrl-X] binding.
     @handle("c-w", filter=main_buffer_focussed)
     def _(event):
-        " Select other window. "
+        "Select other window."
         _select_other_window(history)
 
     @handle("f4")
     def _(event):
-        " Switch between Emacs/Vi mode. "
+        "Switch between Emacs/Vi mode."
         python_input.vi_mode = not python_input.vi_mode
 
     @handle("f1")
     def _(event):
-        " Display/hide help. "
+        "Display/hide help."
         _toggle_help(history)
 
     @handle("enter", filter=help_focussed)
@@ -531,7 +531,7 @@ def create_key_bindings(history, python_input, history_mapping):
     @handle("c-g", filter=help_focussed)
     @handle("escape", filter=help_focussed)
     def _(event):
-        " Leave help. "
+        "Leave help."
         event.app.layout.focus_previous()
 
     @handle("q", filter=main_buffer_focussed)
@@ -539,19 +539,19 @@ def create_key_bindings(history, python_input, history_mapping):
     @handle("c-c", filter=main_buffer_focussed)
     @handle("c-g", filter=main_buffer_focussed)
     def _(event):
-        " Cancel and go back. "
+        "Cancel and go back."
         event.app.exit(result=None)
 
     @handle("enter", filter=main_buffer_focussed)
     def _(event):
-        " Accept input. "
+        "Accept input."
         event.app.exit(result=history.default_buffer.text)
 
     enable_system_bindings = Condition(lambda: python_input.enable_system_bindings)
 
     @handle("c-z", filter=enable_system_bindings)
     def _(event):
-        " Suspend to background. "
+        "Suspend to background."
         event.app.suspend_to_background()
 
     return bindings
@@ -630,7 +630,7 @@ class PythonHistory:
                 )
 
     def _history_buffer_pos_changed(self, _):
-        """ When the cursor changes in the history buffer. Synchronize. """
+        """When the cursor changes in the history buffer. Synchronize."""
         # Only when this buffer has the focus.
         if self.app.current_buffer == self.history_buffer:
             line_no = self.history_buffer.document.cursor_position_row
diff --git a/ptpython/ipython.py b/ptpython/ipython.py
index 2e8d119..9163334 100644
--- a/ptpython/ipython.py
+++ b/ptpython/ipython.py
@@ -282,4 +282,21 @@ def embed(**kwargs):
         kwargs["config"] = config
     shell = InteractiveShellEmbed.instance(**kwargs)
     initialize_extensions(shell, config["InteractiveShellApp"]["extensions"])
+    run_startup_scripts(shell)
     shell(header=header, stack_depth=2, compile_flags=compile_flags)
+
+
+def run_startup_scripts(shell):
+    """
+    Contributed by linyuxu:
+    https://github.com/prompt-toolkit/ptpython/issues/126#issue-161242480
+    """
+    import glob
+    import os
+
+    startup_dir = shell.profile_dir.startup_dir
+    startup_files = []
+    startup_files += glob.glob(os.path.join(startup_dir, "*.py"))
+    startup_files += glob.glob(os.path.join(startup_dir, "*.ipy"))
+    for file in startup_files:
+        shell.run_cell(open(file).read())
diff --git a/ptpython/key_bindings.py b/ptpython/key_bindings.py
index 86317f9..ae23a3d 100644
--- a/ptpython/key_bindings.py
+++ b/ptpython/key_bindings.py
@@ -203,7 +203,7 @@ def load_python_bindings(python_input):
 
     @handle("c-c", filter=has_focus(python_input.default_buffer))
     def _(event):
-        " Abort when Control-C has been pressed. "
+        "Abort when Control-C has been pressed."
         event.app.exit(exception=KeyboardInterrupt, style="class:aborting")
 
     return bindings
@@ -222,7 +222,7 @@ def load_sidebar_bindings(python_input):
     @handle("c-p", filter=sidebar_visible)
     @handle("k", filter=sidebar_visible)
     def _(event):
-        " Go to previous option. "
+        "Go to previous option."
         python_input.selected_option_index = (
             python_input.selected_option_index - 1
         ) % python_input.option_count
@@ -231,7 +231,7 @@ def load_sidebar_bindings(python_input):
     @handle("c-n", filter=sidebar_visible)
     @handle("j", filter=sidebar_visible)
     def _(event):
-        " Go to next option. "
+        "Go to next option."
         python_input.selected_option_index = (
             python_input.selected_option_index + 1
         ) % python_input.option_count
@@ -240,14 +240,14 @@ def load_sidebar_bindings(python_input):
     @handle("l", filter=sidebar_visible)
     @handle(" ", filter=sidebar_visible)
     def _(event):
-        " Select next value for current option. "
+        "Select next value for current option."
         option = python_input.selected_option
         option.activate_next()
 
     @handle("left", filter=sidebar_visible)
     @handle("h", filter=sidebar_visible)
     def _(event):
-        " Select previous value for current option. "
+        "Select previous value for current option."
         option = python_input.selected_option
         option.activate_previous()
 
@@ -257,7 +257,7 @@ def load_sidebar_bindings(python_input):
     @handle("enter", filter=sidebar_visible)
     @handle("escape", filter=sidebar_visible)
     def _(event):
-        " Hide sidebar. "
+        "Hide sidebar."
         python_input.show_sidebar = False
         event.app.layout.focus_last()
 
diff --git a/ptpython/layout.py b/ptpython/layout.py
index 6482cbd..dc6b19b 100644
--- a/ptpython/layout.py
+++ b/ptpython/layout.py
@@ -64,7 +64,7 @@ __all__ = ["PtPythonLayout", "CompletionVisualisation"]
 
 
 class CompletionVisualisation(Enum):
-    " Visualisation method for the completions. "
+    "Visualisation method for the completions."
     NONE = "none"
     POP_UP = "pop-up"
     MULTI_COLUMN = "multi-column"
@@ -116,7 +116,7 @@ def python_sidebar(python_input: "PythonInput") -> Window:
 
             @if_mousedown
             def goto_next(mouse_event: MouseEvent) -> None:
-                " Select item and go to next value. "
+                "Select item and go to next value."
                 python_input.selected_option_index = index
                 option = python_input.selected_option
                 option.activate_next()
@@ -472,7 +472,7 @@ def show_sidebar_button_info(python_input: "PythonInput") -> Container:
 
     @if_mousedown
     def toggle_sidebar(mouse_event: MouseEvent) -> None:
-        " Click handler for the menu. "
+        "Click handler for the menu."
         python_input.show_sidebar = not python_input.show_sidebar
 
     version = sys.version_info
@@ -544,7 +544,7 @@ def meta_enter_message(python_input: "PythonInput") -> Container:
 
     @Condition
     def extra_condition() -> bool:
-        " Only show when... "
+        "Only show when..."
         b = python_input.default_buffer
 
         return (
@@ -646,7 +646,7 @@ class PtPythonLayout:
         sidebar = python_sidebar(python_input)
         self.exit_confirmation = create_exit_confirmation(python_input)
 
-        root_container = HSplit(
+        self.root_container = HSplit(
             [
                 VSplit(
                     [
@@ -759,5 +759,5 @@ class PtPythonLayout:
             ]
         )
 
-        self.layout = Layout(root_container)
+        self.layout = Layout(self.root_container)
         self.sidebar = sidebar
diff --git a/ptpython/prompt_style.py b/ptpython/prompt_style.py
index 24e5f88..e7334af 100644
--- a/ptpython/prompt_style.py
+++ b/ptpython/prompt_style.py
@@ -16,7 +16,7 @@ class PromptStyle(metaclass=ABCMeta):
 
     @abstractmethod
     def in_prompt(self) -> AnyFormattedText:
-        " Return the input tokens. "
+        "Return the input tokens."
         return []
 
     @abstractmethod
@@ -31,7 +31,7 @@ class PromptStyle(metaclass=ABCMeta):
 
     @abstractmethod
     def out_prompt(self) -> AnyFormattedText:
-        " Return the output tokens. "
+        "Return the output tokens."
         return []
 
 
diff --git a/ptpython/python_input.py b/ptpython/python_input.py
index e63cdf1..1785f52 100644
--- a/ptpython/python_input.py
+++ b/ptpython/python_input.py
@@ -4,7 +4,6 @@ This can be used for creation of Python REPLs.
 """
 import __future__
 
-import threading
 from asyncio import get_event_loop
 from functools import partial
 from typing import TYPE_CHECKING, Any, Callable, Dict, Generic, List, Optional, TypeVar
@@ -174,6 +173,11 @@ class PythonInput:
 
         python_input = PythonInput(...)
         python_code = python_input.app.run()
+
+    :param create_app: When `False`, don't create and manage a prompt_toolkit
+                       application. The default is `True` and should only be set
+                       to false if PythonInput is being embedded in a separate
+                       prompt_toolkit application.
     """
 
     def __init__(
@@ -188,6 +192,7 @@ class PythonInput:
         output: Optional[Output] = None,
         # For internal use.
         extra_key_bindings: Optional[KeyBindings] = None,
+        create_app=True,
         _completer: Optional[Completer] = None,
         _validator: Optional[Validator] = None,
         _lexer: Optional[Lexer] = None,
@@ -380,10 +385,16 @@ class PythonInput:
             extra_toolbars=self._extra_toolbars,
         )
 
-        self.app = self._create_application(input, output)
-
-        if vi_mode:
-            self.app.editing_mode = EditingMode.VI
+        # Create an app if requested. If not, the global get_app() is returned
+        # for self.app via property getter.
+        if create_app:
+            self._app: Optional[Application] = self._create_application(input, output)
+            # Setting vi_mode will not work unless the prompt_toolkit
+            # application has been created.
+            if vi_mode:
+                self.app.editing_mode = EditingMode.VI
+        else:
+            self._app = None
 
     def _accept_handler(self, buff: Buffer) -> bool:
         app = get_app()
@@ -393,12 +404,12 @@ class PythonInput:
 
     @property
     def option_count(self) -> int:
-        " Return the total amount of options. (In all categories together.) "
+        "Return the total amount of options. (In all categories together.)"
         return sum(len(category.options) for category in self.options)
 
     @property
     def selected_option(self) -> Option:
-        " Return the currently selected option. "
+        "Return the currently selected option."
         i = 0
         for category in self.options:
             for o in category.options:
@@ -521,7 +532,7 @@ class PythonInput:
         def simple_option(
             title: str, description: str, field_name: str, values: Optional[List] = None
         ) -> Option:
-            " Create Simple on/of option. "
+            "Create Simple on/of option."
             values = values or ["off", "on"]
 
             def get_current_value():
@@ -914,23 +925,19 @@ class PythonInput:
         else:
             self.editing_mode = EditingMode.EMACS
 
-    def _on_input_timeout(self, buff: Buffer, loop=None) -> None:
+    @property
+    def app(self) -> Application:
+        if self._app is None:
+            return get_app()
+        return self._app
+
+    def _on_input_timeout(self, buff: Buffer) -> None:
         """
         When there is no input activity,
         in another thread, get the signature of the current code.
         """
-        app = self.app
-
-        # Never run multiple get-signature threads.
-        if self._get_signatures_thread_running:
-            return
-        self._get_signatures_thread_running = True
 
-        document = buff.document
-
-        loop = loop or get_event_loop()
-
-        def run():
+        def get_signatures_in_executor(document: Document) -> List[Signature]:
             # First, get signatures from Jedi. If we didn't found any and if
             # "dictionary completion" (eval-based completion) is enabled, then
             # get signatures using eval.
@@ -942,26 +949,47 @@ class PythonInput:
                     document, self.get_locals(), self.get_globals()
                 )
 
-            self._get_signatures_thread_running = False
+            return signatures
+
+        app = self.app
 
-            # Set signatures and redraw if the text didn't change in the
-            # meantime. Otherwise request new signatures.
-            if buff.text == document.text:
-                self.signatures = signatures
+        async def on_timeout_task() -> None:
+            loop = get_event_loop()
 
-                # Set docstring in docstring buffer.
-                if signatures:
-                    self.docstring_buffer.reset(
-                        document=Document(signatures[0].docstring, cursor_position=0)
+            # Never run multiple get-signature threads.
+            if self._get_signatures_thread_running:
+                return
+            self._get_signatures_thread_running = True
+
+            try:
+                while True:
+                    document = buff.document
+                    signatures = await loop.run_in_executor(
+                        None, get_signatures_in_executor, document
                     )
-                else:
-                    self.docstring_buffer.reset()
 
-                app.invalidate()
+                    # If the text didn't change in the meantime, take these
+                    # signatures. Otherwise, try again.
+                    if buff.text == document.text:
+                        break
+            finally:
+                self._get_signatures_thread_running = False
+
+            # Set signatures and redraw.
+            self.signatures = signatures
+
+            # Set docstring in docstring buffer.
+            if signatures:
+                self.docstring_buffer.reset(
+                    document=Document(signatures[0].docstring, cursor_position=0)
+                )
             else:
-                self._on_input_timeout(buff, loop=loop)
+                self.docstring_buffer.reset()
+
+            app.invalidate()
 
-        loop.run_in_executor(None, run)
+        if app.is_running:
+            app.create_background_task(on_timeout_task())
 
     def on_reset(self) -> None:
         self.signatures = []
@@ -970,7 +998,7 @@ class PythonInput:
         """
         Display the history.
         """
-        app = get_app()
+        app = self.app
         app.vi_state.input_mode = InputMode.NAVIGATION
 
         history = PythonHistory(self, self.default_buffer.document)
@@ -1012,43 +1040,25 @@ class PythonInput:
                 self.app.vi_state.input_mode = InputMode.NAVIGATION
 
         # Run the UI.
-        result: str = ""
-        exception: Optional[BaseException] = None
-
-        def in_thread() -> None:
-            nonlocal result, exception
+        while True:
             try:
-                while True:
-                    try:
-                        result = self.app.run(pre_run=pre_run)
-
-                        if result.lstrip().startswith("\x1a"):
-                            # When the input starts with Ctrl-Z, quit the REPL.
-                            # (Important for Windows users.)
-                            raise EOFError
-
-                        # Remove leading whitespace.
-                        # (Users can add extra indentation, which happens for
-                        # instance because of copy/pasting code.)
-                        result = unindent_code(result)
-
-                        if result and not result.isspace():
-                            return
-                    except KeyboardInterrupt:
-                        # Abort - try again.
-                        self.default_buffer.document = Document()
-                    except BaseException as e:
-                        exception = e
-                        return
-
-            finally:
-                if self.insert_blank_line_after_input:
-                    self.app.output.write("\n")
-
-        thread = threading.Thread(target=in_thread)
-        thread.start()
-        thread.join()
-
-        if exception is not None:
-            raise exception
-        return result
+                result = self.app.run(pre_run=pre_run, in_thread=True)
+
+                if result.lstrip().startswith("\x1a"):
+                    # When the input starts with Ctrl-Z, quit the REPL.
+                    # (Important for Windows users.)
+                    raise EOFError
+
+                # Remove leading whitespace.
+                # (Users can add extra indentation, which happens for
+                # instance because of copy/pasting code.)
+                result = unindent_code(result)
+
+                if result and not result.isspace():
+                    if self.insert_blank_line_after_input:
+                        self.app.output.write("\n")
+
+                    return result
+            except KeyboardInterrupt:
+                # Abort - try again.
+                self.default_buffer.document = Document()
diff --git a/ptpython/repl.py b/ptpython/repl.py
index ae7b1d0..220c673 100644
--- a/ptpython/repl.py
+++ b/ptpython/repl.py
@@ -11,7 +11,6 @@ import asyncio
 import builtins
 import os
 import sys
-import threading
 import traceback
 import types
 import warnings
@@ -80,7 +79,7 @@ class PythonRepl(PythonInput):
         self._load_start_paths()
 
     def _load_start_paths(self) -> None:
-        " Start the Read-Eval-Print Loop. "
+        "Start the Read-Eval-Print Loop."
         if self._startup_paths:
             for path in self._startup_paths:
                 if os.path.exists(path):
@@ -91,6 +90,35 @@ class PythonRepl(PythonInput):
                     output = self.app.output
                     output.write("WARNING | File not found: {}\n\n".format(path))
 
+    def run_and_show_expression(self, expression):
+        try:
+            # Eval.
+            try:
+                result = self.eval(expression)
+            except KeyboardInterrupt:  # KeyboardInterrupt doesn't inherit from Exception.
+                raise
+            except SystemExit:
+                raise
+            except BaseException as e:
+                self._handle_exception(e)
+            else:
+                # Print.
+                if result is not None:
+                    self.show_result(result)
+
+                # Loop.
+                self.current_statement_index += 1
+                self.signatures = []
+
+        except KeyboardInterrupt as e:
+            # Handle all possible `KeyboardInterrupt` errors. This can
+            # happen during the `eval`, but also during the
+            # `show_result` if something takes too long.
+            # (Try/catch is around the whole block, because we want to
+            # prevent that a Control-C keypress terminates the REPL in
+            # any case.)
+            self._handle_keyboard_interrupt(e)
+
     def run(self) -> None:
         """
         Run the REPL loop.
@@ -102,44 +130,41 @@ class PythonRepl(PythonInput):
 
         try:
             while True:
+                # Pull text from the user.
                 try:
-                    # Read.
-                    try:
-                        text = self.read()
-                    except EOFError:
-                        return
-
-                    # Eval.
-                    try:
-                        result = self.eval(text)
-                    except KeyboardInterrupt as e:  # KeyboardInterrupt doesn't inherit from Exception.
-                        raise
-                    except SystemExit:
-                        return
-                    except BaseException as e:
-                        self._handle_exception(e)
-                    else:
-                        # Print.
-                        if result is not None:
-                            self.show_result(result)
-
-                        # Loop.
-                        self.current_statement_index += 1
-                        self.signatures = []
+                    text = self.read()
+                except EOFError:
+                    return
 
-                except KeyboardInterrupt as e:
-                    # Handle all possible `KeyboardInterrupt` errors. This can
-                    # happen during the `eval`, but also during the
-                    # `show_result` if something takes too long.
-                    # (Try/catch is around the whole block, because we want to
-                    # prevent that a Control-C keypress terminates the REPL in
-                    # any case.)
-                    self._handle_keyboard_interrupt(e)
+                # Run it; display the result (or errors if applicable).
+                self.run_and_show_expression(text)
         finally:
             if self.terminal_title:
                 clear_title()
             self._remove_from_namespace()
 
+    async def run_and_show_expression_async(self, text):
+        loop = asyncio.get_event_loop()
+
+        try:
+            result = await self.eval_async(text)
+        except KeyboardInterrupt:  # KeyboardInterrupt doesn't inherit from Exception.
+            raise
+        except SystemExit:
+            return
+        except BaseException as e:
+            self._handle_exception(e)
+        else:
+            # Print.
+            if result is not None:
+                await loop.run_in_executor(None, lambda: self.show_result(result))
+
+            # Loop.
+            self.current_statement_index += 1
+            self.signatures = []
+            # Return the result for future consumers.
+            return result
+
     async def run_async(self) -> None:
         """
         Run the REPL loop, but run the blocking parts in an executor, so that
@@ -169,24 +194,7 @@ class PythonRepl(PythonInput):
                         return
 
                     # Eval.
-                    try:
-                        result = await self.eval_async(text)
-                    except KeyboardInterrupt as e:  # KeyboardInterrupt doesn't inherit from Exception.
-                        raise
-                    except SystemExit:
-                        return
-                    except BaseException as e:
-                        self._handle_exception(e)
-                    else:
-                        # Print.
-                        if result is not None:
-                            await loop.run_in_executor(
-                                None, lambda: self.show_result(result)
-                            )
-
-                        # Loop.
-                        self.current_statement_index += 1
-                        self.signatures = []
+                    await self.run_and_show_expression_async(text)
 
                 except KeyboardInterrupt as e:
                     # XXX: This does not yet work properly. In some situations,
@@ -231,7 +239,10 @@ class PythonRepl(PythonInput):
             # above, then `sys.exc_info()` would not report the right error.
             # See issue: https://github.com/prompt-toolkit/ptpython/issues/435
             code = self._compile_with_flags(line, "exec")
-            exec(code, self.get_globals(), self.get_locals())
+            result = eval(code, self.get_globals(), self.get_locals())
+
+            if _has_coroutine_flag(code):
+                result = asyncio.get_event_loop().run_until_complete(result)
 
         return None
 
@@ -263,9 +274,14 @@ class PythonRepl(PythonInput):
                 self._store_eval_result(result)
                 return result
 
-            # If not a valid `eval` expression, run using `exec` instead.
+            # If not a valid `eval` expression, compile as `exec` expression
+            # but still run with eval to get an awaitable in case of a
+            # awaitable expression.
             code = self._compile_with_flags(line, "exec")
-            exec(code, self.get_globals(), self.get_locals())
+            result = eval(code, self.get_globals(), self.get_locals())
+
+            if _has_coroutine_flag(code):
+                result = await result
 
         return None
 
@@ -277,7 +293,7 @@ class PythonRepl(PythonInput):
         return super().get_compiler_flags() | PyCF_ALLOW_TOP_LEVEL_AWAIT
 
     def _compile_with_flags(self, code: str, mode: str):
-        " Compile code with the right compiler flags. "
+        "Compile code with the right compiler flags."
         return compile(
             code,
             "<stdin>",
@@ -286,9 +302,9 @@ class PythonRepl(PythonInput):
             dont_inherit=True,
         )
 
-    def show_result(self, result: object) -> None:
+    def _format_result_output(self, result: object) -> StyleAndTextTuples:
         """
-        Show __repr__ for an `eval` result.
+        Format __repr__ for an `eval` result.
 
         Note: this can raise `KeyboardInterrupt` if either calling `__repr__`,
               `__pt_repr__` or formatting the output with "Black" takes to long
@@ -304,7 +320,7 @@ class PythonRepl(PythonInput):
         except BaseException as e:
             # Calling repr failed.
             self._handle_exception(e)
-            return
+            return []
 
         try:
             compile(result_repr, "", "eval")
@@ -315,12 +331,15 @@ class PythonRepl(PythonInput):
             if self.enable_output_formatting:
                 # Inline import. Slightly speed up start-up time if black is
                 # not used.
-                import black
-
-                result_repr = black.format_str(
-                    result_repr,
-                    mode=black.FileMode(line_length=self.app.output.get_size().columns),
-                )
+                try:
+                    import black
+                except ImportError:
+                    pass  #   no Black package in your installation
+                else:
+                    result_repr = black.format_str(
+                        result_repr,
+                        mode=black.Mode(line_length=self.app.output.get_size().columns),
+                    )
 
             formatted_result_repr = to_formatted_text(
                 PygmentsTokens(list(_lex_python_result(result_repr)))
@@ -363,10 +382,18 @@ class PythonRepl(PythonInput):
                 out_prompt + [("", fragment_list_to_text(formatted_result_repr))]
             )
 
+        return to_formatted_text(formatted_output)
+
+    def show_result(self, result: object) -> None:
+        """
+        Show __repr__ for an `eval` result and print to ouptut.
+        """
+        formatted_text_output = self._format_result_output(result)
+
         if self.enable_pager:
-            self.print_paginated_formatted_text(to_formatted_text(formatted_output))
+            self.print_paginated_formatted_text(formatted_text_output)
         else:
-            self.print_formatted_text(to_formatted_text(formatted_output))
+            self.print_formatted_text(formatted_text_output)
 
         self.app.output.flush()
 
@@ -421,15 +448,7 @@ class PythonRepl(PythonInput):
             # Run pager prompt in another thread.
             # Same as for the input. This prevents issues with nested event
             # loops.
-            pager_result = None
-
-            def in_thread() -> None:
-                nonlocal pager_result
-                pager_result = pager_prompt.prompt()
-
-            th = threading.Thread(target=in_thread)
-            th.start()
-            th.join()
+            pager_result = pager_prompt.prompt(in_thread=True)
 
             if pager_result == PagerResult.ABORT:
                 print("...")
@@ -494,9 +513,7 @@ class PythonRepl(PythonInput):
         """
         return create_pager_prompt(self._current_style, self.title)
 
-    def _handle_exception(self, e: BaseException) -> None:
-        output = self.app.output
-
+    def _format_exception_output(self, e: BaseException) -> PygmentsTokens:
         # Instead of just calling ``traceback.format_exc``, we take the
         # traceback and skip the bottom calls of this framework.
         t, v, tb = sys.exc_info()
@@ -525,9 +542,15 @@ class PythonRepl(PythonInput):
             tokens = list(_lex_python_traceback(tb_str))
         else:
             tokens = [(Token, tb_str)]
+        return PygmentsTokens(tokens)
+
+    def _handle_exception(self, e: BaseException) -> None:
+        output = self.app.output
+
+        tokens = self._format_exception_output(e)
 
         print_formatted_text(
-            PygmentsTokens(tokens),
+            tokens,
             style=self._current_style,
             style_transformation=self.style_transformation,
             include_default_pygments_style=False,
@@ -564,13 +587,13 @@ class PythonRepl(PythonInput):
 
 
 def _lex_python_traceback(tb):
-    " Return token list for traceback string. "
+    "Return token list for traceback string."
     lexer = PythonTracebackLexer()
     return lexer.get_tokens(tb)
 
 
 def _lex_python_result(tb):
-    " Return token list for Python string. "
+    "Return token list for Python string."
     lexer = PythonLexer()
     # Use `get_tokens_unprocessed`, so that we get exactly the same string,
     # without line endings appended. `print_formatted_text` already appends a
@@ -590,7 +613,9 @@ def enable_deprecation_warnings() -> None:
     warnings.filterwarnings("default", category=DeprecationWarning, module="__main__")
 
 
-def run_config(repl: PythonInput, config_file: str = "~/.ptpython/config.py") -> None:
+def run_config(
+    repl: PythonInput, config_file: str = "~/.config/ptpython/config.py"
+) -> None:
     """
     Execute REPL config file.
 
@@ -738,7 +763,7 @@ def create_pager_prompt(
 
     @bindings.add("<any>")
     def _(event: KeyPressEvent) -> None:
-        " Disallow inserting other text. "
+        "Disallow inserting other text."
         pass
 
     style