# The MIT License

#

# Copyright (c) 2009-2011 the bpython authors.

# Copyright (c) 2012-2013,2015 Sebastian Ramacher

#

# Permission is hereby granted, free of charge, to any person obtaining a copy

# of this software and associated documentation files (the "Software"), to deal

# in the Software without restriction, including without limitation the rights

# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

# copies of the Software, and to permit persons to whom the Software is

# furnished to do so, subject to the following conditions:

#

# The above copyright notice and this permission notice shall be included in

# all copies or substantial portions of the Software.

#

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

# THE SOFTWARE.

import code

import inspect

import os

import pkgutil

import pydoc

import shlex

import subprocess

import sys

import tempfile

import textwrap

import time

import traceback

from enum import Enum

from itertools import takewhile

from pathlib import Path

from types import ModuleType

from pygments.token import Token

from pygments.lexers import Python3Lexer

from . import autocomplete, inspection, simpleeval

from .clipboard import get_clipboard, CopyFailed

from .config import getpreferredencoding

from .formatter import Parenthesis

from .history import History

from .lazyre import LazyReCompile

from .paste import PasteHelper, PastePinnwand, PasteFailed

from .patch_linecache import filename_for_console_input

from .translations import _, ngettext

from .importcompletion import ModuleGatherer

class RuntimeTimer:

"""Calculate running time"""

def __init__(self):

self.reset_timer()

self.time = time.monotonic if hasattr(time, "monotonic") else time.time

def __enter__(self):

self.start = self.time()

def __exit__(self, ty, val, tb):

self.last_command = self.time() - self.start

self.running_time += self.last_command

return False

def reset_timer(self):

self.running_time = 0.0

self.last_command = 0.0

def estimate(self):

return self.running_time - self.last_command

class Interpreter(code.InteractiveInterpreter):

"""Source code interpreter for use in bpython."""

bpython_input_re = LazyReCompile(r"<bpython-input-\d+>")

def __init__(self, locals=None, encoding=None):

"""Constructor.

The optional 'locals' argument specifies the dictionary in which code

will be executed; it defaults to a newly created dictionary with key

"__name__" set to "__main__".

The syntaxerror callback can be set at any time and will be called

on a caught syntax error. The purpose for this in bpython is so that

the repl can be instantiated after the interpreter (which it

necessarily must be with the current factoring) and then an exception

callback can be added to the Interpreter instance afterwards - more

specifically, this is so that autoindentation does not occur after a

traceback.

encoding is only used in Python 2, where it may be necessary to add an

encoding comment to a source bytestring before running it.

encoding must be a bytestring in Python 2 because it will be templated

into a bytestring source as part of an encoding comment.

"""

self.encoding = encoding or getpreferredencoding()

self.syntaxerror_callback = None

if locals is None:

# instead of messing with sys.modules, we should modify sys.modules

# in the interpreter instance

sys.modules["__main__"] = main_mod = ModuleType("__main__")

locals = main_mod.__dict__

super().__init__(locals)

self.timer = RuntimeTimer()

def reset_running_time(self):

self.running_time = 0

def runsource(self, source, filename=None, symbol="single", encode="auto"):

"""Execute Python code.

source, filename and symbol are passed on to

code.InteractiveInterpreter.runsource. If encode is True,

an encoding comment will be added to the source.

On Python 3.X, encode will be ignored.

encode should only be used for interactive interpreter input,

files should always already have an encoding comment or be ASCII.

By default an encoding line will be added if no filename is given.

source must be a string

Because adding an encoding comment to a unicode string in Python 2

would cause a syntax error to be thrown which would reference code

the user did not write, setting encoding to True when source is a

unicode string in Python 2 will throw a ValueError."""

if encode and filename is not None:

# files have encoding comments or implicit encoding of ASCII

if encode != "auto":

raise ValueError("shouldn't add encoding line to file contents")

encode = False

if filename is None:

filename = filename_for_console_input(source)

with self.timer:

return code.InteractiveInterpreter.runsource(

self, source, filename, symbol

)

def showsyntaxerror(self, filename=None):

"""Override the regular handler, the code's copied and pasted from

code.py, as per showtraceback, but with the syntaxerror callback called

and the text in a pretty colour."""

if self.syntaxerror_callback is not None:

self.syntaxerror_callback()

exc_type, value, sys.last_traceback = sys.exc_info()

sys.last_type = exc_type

sys.last_value = value

if filename and exc_type is SyntaxError:

# Work hard to stuff the correct filename in the exception

try:

msg, (dummy_filename, lineno, offset, line) = value.args

except:

# Not the format we expect; leave it alone

pass

else:

# Stuff in the right filename and right lineno

# strip linecache line number

if self.bpython_input_re.match(filename):

filename = "<input>"

value = SyntaxError(msg, (filename, lineno, offset, line))

sys.last_value = value

exc_formatted = traceback.format_exception_only(exc_type, value)

self.writetb(exc_formatted)

def showtraceback(self):

"""This needs to override the default traceback thing

so it can put it into a pretty colour and maybe other

stuff, I don't know"""

try:

t, v, tb = sys.exc_info()

sys.last_type = t

sys.last_value = v

sys.last_traceback = tb

tblist = traceback.extract_tb(tb)

del tblist[:1]

for i, (fname, lineno, module, something) in enumerate(tblist):

# strip linecache line number

if self.bpython_input_re.match(fname):

fname = "<input>"

tblist[i] = (fname, lineno, module, something)

l = traceback.format_list(tblist)

if l:

l.insert(0, "Traceback (most recent call last):\n")

l[len(l) :] = traceback.format_exception_only(t, v)

finally:

pass

self.writetb(l)

def writetb(self, lines):

"""This outputs the traceback and should be overridden for anything

fancy."""

for line in lines:

self.write(line)

class MatchesIterator:

"""Stores a list of matches and which one is currently selected if any.

Also responsible for doing the actual replacement of the original line with

the selected match.

A MatchesIterator can be `clear`ed to reset match iteration, and

`update`ed to set what matches will be iterated over."""

def __init__(self):

# word being replaced in the original line of text

self.current_word = ""

# possible replacements for current_word

self.matches = None

# which word is currently replacing the current word

self.index = -1

# cursor position in the original line

self.orig_cursor_offset = None

# original line (before match replacements)

self.orig_line = None

# class describing the current type of completion

self.completer = None

def __nonzero__(self):

"""MatchesIterator is False when word hasn't been replaced yet"""

return self.index != -1

def __bool__(self):

return self.index != -1

@property

def candidate_selected(self):

"""True when word selected/replaced, False when word hasn't been

replaced yet"""

return bool(self)

def __iter__(self):

return self

def current(self):

if self.index == -1:

raise ValueError("No current match.")

return self.matches[self.index]

def next(self):

return self.__next__()

def __next__(self):

self.index = (self.index + 1) % len(self.matches)

return self.matches[self.index]

def previous(self):

if self.index <= 0:

self.index = len(self.matches)

self.index -= 1

return self.matches[self.index]

def cur_line(self):

"""Returns a cursor offset and line with the current substitution

made"""

return self.substitute(self.current())

def substitute(self, match):

"""Returns a cursor offset and line with match substituted in"""

start, end, word = self.completer.locate(

self.orig_cursor_offset, self.orig_line

)

return (

start + len(match),

self.orig_line[:start] + match + self.orig_line[end:],

)

def is_cseq(self):

return bool(

os.path.commonprefix(self.matches)[len(self.current_word) :]

)

def substitute_cseq(self):

"""Returns a new line by substituting a common sequence in, and update

matches"""

cseq = os.path.commonprefix(self.matches)

new_cursor_offset, new_line = self.substitute(cseq)

if len(self.matches) == 1:

self.clear()

else:

self.update(

new_cursor_offset, new_line, self.matches, self.completer

)

if len(self.matches) == 1:

self.clear()

return new_cursor_offset, new_line

def update(self, cursor_offset, current_line, matches, completer):

"""Called to reset the match index and update the word being replaced

Should only be called if there's a target to update - otherwise, call

clear"""

if matches is None:

raise ValueError("Matches may not be None.")

self.orig_cursor_offset = cursor_offset

self.orig_line = current_line

self.matches = matches

self.completer = completer

self.index = -1

self.start, self.end, self.current_word = self.completer.locate(

self.orig_cursor_offset, self.orig_line

)

def clear(self):

self.matches = []

self.cursor_offset = -1

self.current_line = ""

self.current_word = ""

self.start = None

self.end = None

self.index = -1

class Interaction:

def __init__(self, config, statusbar=None):

self.config = config

if statusbar:

self.statusbar = statusbar

def confirm(self, s):

raise NotImplementedError

def notify(self, s, n=10, wait_for_keypress=False):

raise NotImplementedError

def file_prompt(self, s):

raise NotImplementedError

class SourceNotFound(Exception):

"""Exception raised when the requested source could not be found."""

class LineTypeTranslator(Enum):

"""Used when adding a tuple to all_logical_lines, to get input / output values

having to actually type/know the strings"""

INPUT = "input"

OUTPUT = "output"

class Repl:

"""Implements the necessary guff for a Python-repl-alike interface

The execution of the code entered and all that stuff was taken from the

Python code module, I had to copy it instead of inheriting it, I can't

remember why. The rest of the stuff is basically what makes it fancy.

It reads what you type, passes it to a lexer and highlighter which

returns a formatted string. This then gets passed to echo() which

parses that string and prints to the curses screen in appropriate

colours and/or bold attribute.

The Repl class also keeps two stacks of lines that the user has typed in:

One to be used for the undo feature. I am not happy with the way this

works. The only way I have been able to think of is to keep the code

that's been typed in in memory and re-evaluate it in its entirety for each

"undo" operation. Obviously this means some operations could be extremely

slow. I'm not even by any means certain that this truly represents a

genuine "undo" implementation, but it does seem to be generally pretty

effective.

If anyone has any suggestions for how this could be improved, I'd be happy

to hear them and implement it/accept a patch. I researched a bit into the

idea of keeping the entire Python state in memory, but this really seems

very difficult (I believe it may actually be impossible to work) and has

its own problems too.

The other stack is for keeping a history for pressing the up/down keys

to go back and forth between lines.

XXX Subclasses should implement echo, current_line, cw

"""

def __init__(self, interp, config):

"""Initialise the repl.

interp is a Python code.InteractiveInterpreter instance

config is a populated bpython.config.Struct.

"""

self.config = config

self.cut_buffer = ""

self.buffer = []

self.interp = interp

self.interp.syntaxerror_callback = self.clear_current_line

self.match = False

self.rl_history = History(

duplicates=config.hist_duplicates, hist_size=config.hist_length

)

# all input and output, stored as old style format strings

# (\x01, \x02, ...) for cli.py

self.screen_hist = []

self.history = [] # commands executed since beginning of session

self.redo_stack = []

self.evaluating = False

self.matches_iter = MatchesIterator()

self.funcprops = None

self.arg_pos = None

self.current_func = None

self.highlighted_paren = None

self._C = {}

self.prev_block_finished = 0

self.interact = Interaction(self.config)

# previous pastebin content to prevent duplicate pastes, filled on call

# to repl.pastebin

self.prev_pastebin_content = ""

self.prev_pastebin_url = ""

self.prev_removal_url = ""

# Necessary to fix mercurial.ui.ui expecting sys.stderr to have this

# attribute

self.closed = False

self.clipboard = get_clipboard()

if self.config.hist_file.exists():

try:

self.rl_history.load(

self.config.hist_file, getpreferredencoding() or "ascii"

)

except OSError:

pass

self.module_gatherer = ModuleGatherer(

skiplist=self.config.import_completion_skiplist

)

self.completers = autocomplete.get_default_completer(

config.autocomplete_mode, self.module_gatherer

)

if self.config.pastebin_helper:

self.paster = PasteHelper(self.config.pastebin_helper)

else:

self.paster = PastePinnwand(

self.config.pastebin_url,

self.config.pastebin_expiry,

)

@property

def ps1(self):

try:

return sys.ps1

except AttributeError:

return ">>> "

@property

def ps2(self):

try:

return sys.ps2

except AttributeError:

return "... "

def startup(self):

"""

Execute PYTHONSTARTUP file if it exits. Call this after front

end-specific initialisation.

"""

filename = os.environ.get("PYTHONSTARTUP")

if filename:

encoding = inspection.get_encoding_file(filename)

with open(filename, encoding=encoding) as f:

source = f.read()

self.interp.runsource(source, filename, "exec", encode=False)

def current_string(self, concatenate=False):

"""If the line ends in a string get it, otherwise return ''"""

tokens = self.tokenize(self.current_line)

string_tokens = list(

takewhile(

token_is_any_of([Token.String, Token.Text]), reversed(tokens)

)

)

if not string_tokens:

return ""

opening = string_tokens.pop()[1]

string = list()

for (token, value) in reversed(string_tokens):

if token is Token.Text:

continue

elif opening is None:

opening = value

elif token is Token.String.Doc:

string.append(value[3:-3])

opening = None

elif value == opening:

opening = None

if not concatenate:

string = list()

else:

string.append(value)

if opening is None:

return ""

return "".join(string)

def get_object(self, name):

attributes = name.split(".")

obj = eval(attributes.pop(0), self.interp.locals)

while attributes:

with inspection.AttrCleaner(obj):

obj = getattr(obj, attributes.pop(0))

return obj

@classmethod

def _funcname_and_argnum(cls, line):

"""Parse out the current function name and arg from a line of code."""

# each list in stack:

# [full_expr, function_expr, arg_number, opening]

# arg_number may be a string if we've encountered a keyword

# argument so we're done counting

stack = [["", "", 0, ""]]

try:

for (token, value) in Python3Lexer().get_tokens(line):

if token is Token.Punctuation:

if value in "([{":

stack.append(["", "", 0, value])

elif value in ")]}":

full, _, _, start = stack.pop()

expr = start + full + value

stack[-1][1] += expr

stack[-1][0] += expr

elif value == ",":

try:

stack[-1][2] += 1

except TypeError:

stack[-1][2] = ""

stack[-1][1] = ""

stack[-1][0] += value

elif value == ":" and stack[-1][3] == "lambda":

expr = stack.pop()[0] + ":"

stack[-1][1] += expr

stack[-1][0] += expr

else:

stack[-1][1] = ""

stack[-1][0] += value

elif (

token is Token.Number

or token in Token.Number.subtypes

or token is Token.Name

or token in Token.Name.subtypes

or token is Token.Operator

and value == "."

):

stack[-1][1] += value

stack[-1][0] += value

elif token is Token.Operator and value == "=":

stack[-1][2] = stack[-1][1]

stack[-1][1] = ""

stack[-1][0] += value

elif token is Token.Number or token in Token.Number.subtypes:

stack[-1][1] = value

stack[-1][0] += value

elif token is Token.Keyword and value == "lambda":

stack.append([value, "", 0, value])

else:

stack[-1][1] = ""

stack[-1][0] += value

while stack[-1][3] in "[{":

stack.pop()

_, _, arg_number, _ = stack.pop()

_, func, _, _ = stack.pop()

return func, arg_number

except IndexError:

return None, None

def get_args(self):

"""Check if an unclosed parenthesis exists, then attempt to get the

argspec() for it. On success, update self.funcprops,self.arg_pos and

return True, otherwise set self.funcprops to None and return False"""

self.current_func = None

if not self.config.arg_spec:

return False

func, arg_number = self._funcname_and_argnum(self.current_line)

if not func:

return False

try:

if inspection.is_eval_safe_name(func):

f = self.get_object(func)

else:

try:

fake_cursor = self.current_line.index(func) + len(func)

f = simpleeval.evaluate_current_attribute(

fake_cursor, self.current_line, self.interp.locals

)

except simpleeval.EvaluationError:

return False

if inspect.isclass(f):

class_f = None

if hasattr(f, "__init__") and f.__init__ is not object.__init__:

class_f = f.__init__

if (

(not class_f or not inspection.getfuncprops(func, class_f))

and hasattr(f, "__new__")

and f.__new__ is not object.__new__

and

# py3

f.__new__.__class__ is not object.__new__.__class__

):

class_f = f.__new__

if class_f:

f = class_f

except Exception:

# another case of needing to catch every kind of error

# since user code is run in the case of descriptors

# XXX: Make sure you raise here if you're debugging the completion

# stuff !

return False

self.current_func = f

self.funcprops = inspection.getfuncprops(func, f)

if self.funcprops:

self.arg_pos = arg_number

return True

self.arg_pos = None

return False

def get_source_of_current_name(self):

"""Return the unicode source code of the object which is bound to the

current name in the current input line. Throw `SourceNotFound` if the

source cannot be found."""

obj = self.current_func

try:

if obj is None:

line = self.current_line

if not line.strip():

raise SourceNotFound(_("Nothing to get source of"))

if inspection.is_eval_safe_name(line):

obj = self.get_object(line)

return inspection.get_source_unicode(obj)

except (AttributeError, NameError) as e:

msg = _("Cannot get source: %s") % (e,)

except OSError as e:

msg = f"{e}"

except TypeError as e:

if "built-in" in f"{e}":

msg = _("Cannot access source of %r") % (obj,)

else:

msg = _("No source code found for %s") % (self.current_line,)

raise SourceNotFound(msg)

def set_docstring(self):

self.docstring = None

if not self.get_args():

self.funcprops = None

if self.current_func is not None:

try:

self.docstring = pydoc.getdoc(self.current_func)

except IndexError:

self.docstring = None

else:

# pydoc.getdoc() returns an empty string if no

# docstring was found

if not self.docstring:

self.docstring = None

# What complete() does:

# Should we show the completion box? (are there matches, or is there a

# docstring to show?)

# Some completions should always be shown, other only if tab=True

# set the current docstring to the "current function's" docstring

# Populate the matches_iter object with new matches from the current state

# if none, clear the matches iterator

# If exactly one match that is equal to current line, clear matches

# If example one match and tab=True, then choose that and clear matches

def complete(self, tab=False):

"""Construct a full list of possible completions and

display them in a window. Also check if there's an available argspec

(via the inspect module) and bang that on top of the completions too.

The return value is whether the list_win is visible or not.

If no matches are found, just return whether there's an argspec to show

If any matches are found, save them and select the first one.

If tab is True exactly one match found, make the replacement and return

the result of running complete() again on the new line.

"""

self.set_docstring()

matches, completer = autocomplete.get_completer(

self.completers,

cursor_offset=self.cursor_offset,

line=self.current_line,

locals_=self.interp.locals,

argspec=self.funcprops,

current_block="\n".join(self.buffer + [self.current_line]),

complete_magic_methods=self.config.complete_magic_methods,

history=self.history,

)

if len(matches) == 0:

self.matches_iter.clear()

return bool(self.funcprops)

self.matches_iter.update(

self.cursor_offset, self.current_line, matches, completer

)

if len(matches) == 1:

if tab:

# if this complete is being run for a tab key press, substitute

# common sequence

(

self._cursor_offset,

self._current_line,

) = self.matches_iter.substitute_cseq()

return Repl.complete(self) # again for

elif self.matches_iter.current_word == matches[0]:

self.matches_iter.clear()

return False

return completer.shown_before_tab

else:

return tab or completer.shown_before_tab

def format_docstring(self, docstring, width, height):

"""Take a string and try to format it into a sane list of strings to be

put into the suggestion box."""

lines = docstring.split("\n")

out = []

i = 0

for line in lines:

i += 1

if not line.strip():

out.append("\n")

for block in textwrap.wrap(line, width):

out.append(" " + block + "\n")

if i >= height:

return out

i += 1

# Drop the last newline

out[-1] = out[-1].rstrip()

return out

def next_indentation(self):

"""Return the indentation of the next line based on the current

input buffer."""

if self.buffer:

indentation = next_indentation(

self.buffer[-1], self.config.tab_length

)

if indentation and self.config.dedent_after > 0:

def line_is_empty(line):

return not line.strip()

empty_lines = takewhile(line_is_empty, reversed(self.buffer))

if sum(1 for _ in empty_lines) >= self.config.dedent_after:

indentation -= 1

else:

indentation = 0

return indentation

def get_session_formatted_for_file(self):

"""Format the stdout buffer to something suitable for writing to disk,

i.e. without >>> and ... at input lines and with "# OUT: " prepended to

output lines and "### " prepended to current line"""

if hasattr(self, "all_logical_lines"):

# Curtsies

def process():

for line, lineType in self.all_logical_lines:

if lineType == LineTypeTranslator.INPUT:

yield line

elif line.rstrip():

yield "# OUT: %s" % line

yield "### %s" % self.current_line

return "\n".join(process())

else: # cli and Urwid

session_output = self.getstdout()

def process():

for line in session_output.split("\n"):

if line.startswith(self.ps1):

yield line[len(self.ps1) :]

elif line.startswith(self.ps2):

yield line[len(self.ps2) :]

elif line.rstrip():

yield f"# OUT: {line}"

return "\n".join(process())

def write2file(self):

"""Prompt for a filename and write the current contents of the stdout

buffer to disk."""

try:

fn = self.interact.file_prompt(_("Save to file (Esc to cancel): "))

if not fn:

self.interact.notify(_("Save cancelled."))

return

except ValueError:

self.interact.notify(_("Save cancelled."))

return

fn = Path(fn).expanduser()

if fn.suffix != ".py" and self.config.save_append_py:

# fn.with_suffix(".py") does not append if fn has a non-empty suffix

fn = Path(f"{fn}.py")

mode = "w"

if fn.exists():

mode = self.interact.file_prompt(

_(

"%s already exists. Do you "

"want to (c)ancel, "

" (o)verwrite or "

"(a)ppend? "

)

% (fn,)

)

if mode in ("o", "overwrite", _("overwrite")):

mode = "w"

elif mode in ("a", "append", _("append")):

mode = "a"

else:

self.interact.notify(_("Save cancelled."))

return

stdout_text = self.get_session_formatted_for_file()

try:

with open(fn, mode) as f:

f.write(stdout_text)

except OSError as e:

self.interact.notify(_("Error writing file '%s': %s") % (fn, e))

else:

self.interact.notify(_("Saved to %s.") % (fn,))

def copy2clipboard(self):

"""Copy current content to clipboard."""

if self.clipboard is None:

self.interact.notify(_("No clipboard available."))

return

content = self.get_session_formatted_for_file()

try:

self.clipboard.copy(content)

except CopyFailed:

self.interact.notify(_("Could not copy to clipboard."))

else:

self.interact.notify(_("Copied content to clipboard."))

def pastebin(self, s=None):

"""Upload to a pastebin and display the URL in the status bar."""

if s is None:

s = self.getstdout()

if self.config.pastebin_confirm and not self.interact.confirm(

_("Pastebin buffer? (y/N) ")

):

self.interact.notify(_("Pastebin aborted."))

return

return self.do_pastebin(s)

def do_pastebin(self, s):

"""Actually perform the upload."""

if s == self.prev_pastebin_content:

self.interact.notify(

_("Duplicate pastebin. Previous URL: %s. " "Removal URL: %s")

% (self.prev_pastebin_url, self.prev_removal_url),

10,

)

return self.prev_pastebin_url

self.interact.notify(_("Posting data to pastebin..."))

try:

paste_url, removal_url = self.paster.paste(s)

except PasteFailed as e:

self.interact.notify(_("Upload failed: %s") % e)

return

self.prev_pastebin_content = s

self.prev_pastebin_url = paste_url

self.prev_removal_url = removal_url

if removal_url is not None:

self.interact.notify(

_("Pastebin URL: %s - Removal URL: %s")

% (paste_url, removal_url),

10,

)

else:

self.interact.notify(_("Pastebin URL: %s") % (paste_url,), 10)

return paste_url

def push(self, s, insert_into_history=True):

"""Push a line of code onto the buffer so it can process it all

at once when a code block ends"""

# This push method is used by cli and urwid, but not curtsies

s = s.rstrip("\n")

self.buffer.append(s)

if insert_into_history:

self.insert_into_history(s)

more = self.interp.runsource("\n".join(self.buffer))

if not more:

self.buffer = []

return more

def insert_into_history(self, s):

try:

self.rl_history.append_reload_and_write(

s, self.config.hist_file, getpreferredencoding()

)

except RuntimeError as e:

self.interact.notify(f"{e}")

def prompt_undo(self):

"""Returns how many lines to undo, 0 means don't undo"""

if (

self.config.single_undo_time < 0

or self.interp.timer.estimate() < self.config.single_undo_time

):

return 1

est = self.interp.timer.estimate()

n = self.interact.file_prompt(

_("Undo how many lines? (Undo will take up to ~%.1f seconds) [1]")

% (est,)

)

try:

if n == "":

n = "1"

n = int(n)

except ValueError:

self.interact.notify(_("Undo canceled"), 0.1)

return 0

else:

if n == 0:

self.interact.notify(_("Undo canceled"), 0.1)

return 0

else:

message = ngettext(

"Undoing %d line... (est. %.1f seconds)",

"Undoing %d lines... (est. %.1f seconds)",

n,

)

self.interact.notify(message % (n, est), 0.1)

return n

def undo(self, n=1):

"""Go back in the undo history n steps and call reevaluate()

Note that in the program this is called "Rewind" because I

want it to be clear that this is by no means a true undo

implementation, it is merely a convenience bonus."""

if not self.history:

return None

self.interp.timer.reset_timer()

if len(self.history) < n:

n = len(self.history)

entries = list(self.rl_history.entries)

# Most recently undone command

last_entries = self.history[-n:]

last_entries.reverse()

self.redo_stack += last_entries

self.history = self.history[:-n]

self.reevaluate()