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cpython/Lib/_pyrepl/reader.py

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# Copyright 2000-2010 Michael Hudson-Doyle <micahel@gmail.com>
# Antonio Cuni
# Armin Rigo
#
# All Rights Reserved
#
#
# Permission to use, copy, modify, and distribute this software and
# its documentation for any purpose is hereby granted without fee,
# provided that the above copyright notice appear in all copies and
# that both that copyright notice and this permission notice appear in
# supporting documentation.
#
# THE AUTHOR MICHAEL HUDSON DISCLAIMS ALL WARRANTIES WITH REGARD TO
# THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
# AND FITNESS, IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL,
# INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
# RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
# CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
from __future__ import annotations
from contextlib import contextmanager
from dataclasses import dataclass, field, fields
import unicodedata
from _colorize import can_colorize, ANSIColors # type: ignore[import-not-found]
from . import commands, console, input
from .utils import ANSI_ESCAPE_SEQUENCE, wlen
from .trace import trace
# types
Command = commands.Command
if False:
from typing import Callable
from .types import Callback, SimpleContextManager, KeySpec, CommandName
CalcScreen = Callable[[], list[str]]
def disp_str(buffer: str) -> tuple[str, list[int]]:
"""disp_str(buffer:string) -> (string, [int])
Return the string that should be the printed represenation of
|buffer| and a list detailing where the characters of |buffer|
get used up. E.g.:
>>> disp_str(chr(3))
('^C', [1, 0])
"""
b: list[int] = []
s: list[str] = []
for c in buffer:
if ord(c) > 128 and unicodedata.category(c).startswith("C"):
c = r"\u%04x" % ord(c)
s.append(c)
b.append(wlen(c))
b.extend([0] * (len(c) - 1))
return "".join(s), b
# syntax classes:
SYNTAX_WHITESPACE, SYNTAX_WORD, SYNTAX_SYMBOL = range(3)
def make_default_syntax_table() -> dict[str, int]:
# XXX perhaps should use some unicodedata here?
st: dict[str, int] = {}
for c in map(chr, range(256)):
st[c] = SYNTAX_SYMBOL
for c in [a for a in map(chr, range(256)) if a.isalnum()]:
st[c] = SYNTAX_WORD
st["\n"] = st[" "] = SYNTAX_WHITESPACE
return st
def make_default_commands() -> dict[CommandName, type[Command]]:
result: dict[CommandName, type[Command]] = {}
for v in vars(commands).values():
if isinstance(v, type) and issubclass(v, Command) and v.__name__[0].islower():
result[v.__name__] = v
result[v.__name__.replace("_", "-")] = v
return result
default_keymap: tuple[tuple[KeySpec, CommandName], ...] = tuple(
[
(r"\C-a", "beginning-of-line"),
(r"\C-b", "left"),
(r"\C-c", "interrupt"),
(r"\C-d", "delete"),
(r"\C-e", "end-of-line"),
(r"\C-f", "right"),
(r"\C-g", "cancel"),
(r"\C-h", "backspace"),
(r"\C-j", "accept"),
(r"\<return>", "accept"),
(r"\C-k", "kill-line"),
(r"\C-l", "clear-screen"),
(r"\C-m", "accept"),
(r"\C-t", "transpose-characters"),
(r"\C-u", "unix-line-discard"),
(r"\C-w", "unix-word-rubout"),
(r"\C-x\C-u", "upcase-region"),
(r"\C-y", "yank"),
(r"\C-z", "suspend"),
(r"\M-b", "backward-word"),
(r"\M-c", "capitalize-word"),
(r"\M-d", "kill-word"),
(r"\M-f", "forward-word"),
(r"\M-l", "downcase-word"),
(r"\M-t", "transpose-words"),
(r"\M-u", "upcase-word"),
(r"\M-y", "yank-pop"),
(r"\M--", "digit-arg"),
(r"\M-0", "digit-arg"),
(r"\M-1", "digit-arg"),
(r"\M-2", "digit-arg"),
(r"\M-3", "digit-arg"),
(r"\M-4", "digit-arg"),
(r"\M-5", "digit-arg"),
(r"\M-6", "digit-arg"),
(r"\M-7", "digit-arg"),
(r"\M-8", "digit-arg"),
(r"\M-9", "digit-arg"),
# (r'\M-\n', 'insert-nl'),
("\\\\", "self-insert"),
(r"\x1b[200~", "enable_bracketed_paste"),
(r"\x1b[201~", "disable_bracketed_paste"),
]
+ [(c, "self-insert") for c in map(chr, range(32, 127)) if c != "\\"]
+ [(c, "self-insert") for c in map(chr, range(128, 256)) if c.isalpha()]
+ [
(r"\<up>", "up"),
(r"\<down>", "down"),
(r"\<left>", "left"),
(r"\C-\<left>", "backward-word"),
(r"\<right>", "right"),
(r"\C-\<right>", "forward-word"),
(r"\<delete>", "delete"),
(r"\<backspace>", "backspace"),
(r"\M-\<backspace>", "backward-kill-word"),
(r"\<end>", "end-of-line"), # was 'end'
(r"\<home>", "beginning-of-line"), # was 'home'
(r"\<f1>", "help"),
(r"\<f2>", "show-history"),
(r"\<f3>", "paste-mode"),
(r"\EOF", "end"), # the entries in the terminfo database for xterms
(r"\EOH", "home"), # seem to be wrong. this is a less than ideal
# workaround
]
)
@dataclass(slots=True)
class Reader:
"""The Reader class implements the bare bones of a command reader,
handling such details as editing and cursor motion. What it does
not support are such things as completion or history support -
these are implemented elsewhere.
Instance variables of note include:
* buffer:
A *list* (*not* a string at the moment :-) containing all the
characters that have been entered.
* console:
Hopefully encapsulates the OS dependent stuff.
* pos:
A 0-based index into `buffer' for where the insertion point
is.
* screeninfo:
Ahem. This list contains some info needed to move the
insertion point around reasonably efficiently.
* cxy, lxy:
the position of the insertion point in screen ...
* syntax_table:
Dictionary mapping characters to `syntax class'; read the
emacs docs to see what this means :-)
* commands:
Dictionary mapping command names to command classes.
* arg:
The emacs-style prefix argument. It will be None if no such
argument has been provided.
* dirty:
True if we need to refresh the display.
* kill_ring:
The emacs-style kill-ring; manipulated with yank & yank-pop
* ps1, ps2, ps3, ps4:
prompts. ps1 is the prompt for a one-line input; for a
multiline input it looks like:
ps2> first line of input goes here
ps3> second and further
ps3> lines get ps3
...
ps4> and the last one gets ps4
As with the usual top-level, you can set these to instances if
you like; str() will be called on them (once) at the beginning
of each command. Don't put really long or newline containing
strings here, please!
This is just the default policy; you can change it freely by
overriding get_prompt() (and indeed some standard subclasses
do).
* finished:
handle1 will set this to a true value if a command signals
that we're done.
"""
console: console.Console
## state
buffer: list[str] = field(default_factory=list)
pos: int = 0
ps1: str = "->> "
ps2: str = "/>> "
ps3: str = "|.. "
ps4: str = R"\__ "
kill_ring: list[list[str]] = field(default_factory=list)
msg: str = ""
arg: int | None = None
dirty: bool = False
finished: bool = False
paste_mode: bool = False
in_bracketed_paste: bool = False
commands: dict[str, type[Command]] = field(default_factory=make_default_commands)
last_command: type[Command] | None = None
syntax_table: dict[str, int] = field(default_factory=make_default_syntax_table)
msg_at_bottom: bool = True
keymap: tuple[tuple[str, str], ...] = ()
input_trans: input.KeymapTranslator = field(init=False)
input_trans_stack: list[input.KeymapTranslator] = field(default_factory=list)
screen: list[str] = field(default_factory=list)
screeninfo: list[tuple[int, list[int]]] = field(init=False)
cxy: tuple[int, int] = field(init=False)
lxy: tuple[int, int] = field(init=False)
calc_screen: CalcScreen = field(init=False)
def __post_init__(self) -> None:
# Enable the use of `insert` without a `prepare` call - necessary to
# facilitate the tab completion hack implemented for
# <https://bugs.python.org/issue25660>.
self.keymap = self.collect_keymap()
self.input_trans = input.KeymapTranslator(
self.keymap, invalid_cls="invalid-key", character_cls="self-insert"
)
self.screeninfo = [(0, [])]
self.cxy = self.pos2xy()
self.lxy = (self.pos, 0)
self.calc_screen = self.calc_complete_screen
def collect_keymap(self) -> tuple[tuple[KeySpec, CommandName], ...]:
return default_keymap
def append_to_screen(self) -> list[str]:
new_screen = self.screen.copy() or ['']
new_character = self.buffer[-1]
new_character_len = wlen(new_character)
last_line_len = wlen(new_screen[-1])
if last_line_len + new_character_len >= self.console.width: # We need to wrap here
new_screen[-1] += '\\'
self.screeninfo[-1][1].append(1)
new_screen.append(self.buffer[-1])
self.screeninfo.append((0, [new_character_len]))
else:
new_screen[-1] += self.buffer[-1]
self.screeninfo[-1][1].append(new_character_len)
self.cxy = self.pos2xy()
# Reset the function that is used for completing the screen
self.calc_screen = self.calc_complete_screen
return new_screen
def calc_complete_screen(self) -> list[str]:
"""The purpose of this method is to translate changes in
self.buffer into changes in self.screen. Currently it rips
everything down and starts from scratch, which whilst not
especially efficient is certainly simple(r).
"""
lines = self.get_unicode().split("\n")
screen: list[str] = []
screeninfo: list[tuple[int, list[int]]] = []
pos = self.pos
for ln, line in enumerate(lines):
ll = len(line)
if 0 <= pos <= ll:
if self.msg and not self.msg_at_bottom:
for mline in self.msg.split("\n"):
screen.append(mline)
screeninfo.append((0, []))
self.lxy = pos, ln
prompt = self.get_prompt(ln, ll >= pos >= 0)
while "\n" in prompt:
pre_prompt, _, prompt = prompt.partition("\n")
screen.append(pre_prompt)
screeninfo.append((0, []))
pos -= ll + 1
prompt, lp = self.process_prompt(prompt)
l, l2 = disp_str(line)
wrapcount = (wlen(l) + lp) // self.console.width
if wrapcount == 0:
screen.append(prompt + l)
screeninfo.append((lp, l2))
else:
for i in range(wrapcount + 1):
prelen = lp if i == 0 else 0
index_to_wrap_before = 0
column = 0
for character_width in l2:
if column + character_width >= self.console.width - prelen:
break
index_to_wrap_before += 1
column += character_width
pre = prompt if i == 0 else ""
post = "\\" if i != wrapcount else ""
after = [1] if i != wrapcount else []
screen.append(pre + l[:index_to_wrap_before] + post)
screeninfo.append((prelen, l2[:index_to_wrap_before] + after))
l = l[index_to_wrap_before:]
l2 = l2[index_to_wrap_before:]
self.screeninfo = screeninfo
self.cxy = self.pos2xy()
if self.msg and self.msg_at_bottom:
for mline in self.msg.split("\n"):
screen.append(mline)
screeninfo.append((0, []))
return screen
def process_prompt(self, prompt: str) -> tuple[str, int]:
"""Process the prompt.
This means calculate the length of the prompt. The character \x01
and \x02 are used to bracket ANSI control sequences and need to be
excluded from the length calculation. So also a copy of the prompt
is returned with these control characters removed."""
# The logic below also ignores the length of common escape
# sequences if they were not explicitly within \x01...\x02.
# They are CSI (or ANSI) sequences ( ESC [ ... LETTER )
out_prompt = ""
l = wlen(prompt)
pos = 0
while True:
s = prompt.find("\x01", pos)
if s == -1:
break
e = prompt.find("\x02", s)
if e == -1:
break
# Found start and end brackets, subtract from string length
l = l - (e - s + 1)
keep = prompt[pos:s]
l -= sum(map(wlen, ANSI_ESCAPE_SEQUENCE.findall(keep)))
out_prompt += keep + prompt[s + 1 : e]
pos = e + 1
keep = prompt[pos:]
l -= sum(map(wlen, ANSI_ESCAPE_SEQUENCE.findall(keep)))
out_prompt += keep
return out_prompt, l
def bow(self, p: int | None = None) -> int:
"""Return the 0-based index of the word break preceding p most
immediately.
p defaults to self.pos; word boundaries are determined using
self.syntax_table."""
if p is None:
p = self.pos
st = self.syntax_table
b = self.buffer
p -= 1
while p >= 0 and st.get(b[p], SYNTAX_WORD) != SYNTAX_WORD:
p -= 1
while p >= 0 and st.get(b[p], SYNTAX_WORD) == SYNTAX_WORD:
p -= 1
return p + 1
def eow(self, p: int | None = None) -> int:
"""Return the 0-based index of the word break following p most
immediately.
p defaults to self.pos; word boundaries are determined using
self.syntax_table."""
if p is None:
p = self.pos
st = self.syntax_table
b = self.buffer
while p < len(b) and st.get(b[p], SYNTAX_WORD) != SYNTAX_WORD:
p += 1
while p < len(b) and st.get(b[p], SYNTAX_WORD) == SYNTAX_WORD:
p += 1
return p
def bol(self, p: int | None = None) -> int:
"""Return the 0-based index of the line break preceding p most
immediately.
p defaults to self.pos."""
if p is None:
p = self.pos
b = self.buffer
p -= 1
while p >= 0 and b[p] != "\n":
p -= 1
return p + 1
def eol(self, p: int | None = None) -> int:
"""Return the 0-based index of the line break following p most
immediately.
p defaults to self.pos."""
if p is None:
p = self.pos
b = self.buffer
while p < len(b) and b[p] != "\n":
p += 1
return p
def max_column(self, y: int) -> int:
"""Return the last x-offset for line y"""
return self.screeninfo[y][0] + sum(self.screeninfo[y][1])
def max_row(self) -> int:
return len(self.screeninfo) - 1
def get_arg(self, default: int = 1) -> int:
"""Return any prefix argument that the user has supplied,
returning `default' if there is None. Defaults to 1.
"""
if self.arg is None:
return default
else:
return self.arg
def get_prompt(self, lineno: int, cursor_on_line: bool) -> str:
"""Return what should be in the left-hand margin for line
`lineno'."""
if self.arg is not None and cursor_on_line:
prompt = "(arg: %s) " % self.arg
elif self.paste_mode:
prompt = "(paste) "
elif "\n" in self.buffer:
if lineno == 0:
prompt = self.ps2
elif self.ps4 and lineno == self.buffer.count("\n"):
prompt = self.ps4
else:
prompt = self.ps3
else:
prompt = self.ps1
if can_colorize():
prompt = f"{ANSIColors.BOLD_MAGENTA}{prompt}{ANSIColors.RESET}"
return prompt
def push_input_trans(self, itrans: input.KeymapTranslator) -> None:
self.input_trans_stack.append(self.input_trans)
self.input_trans = itrans
def pop_input_trans(self) -> None:
self.input_trans = self.input_trans_stack.pop()
def setpos_from_xy(self, x: int, y: int) -> None:
"""Set pos according to coordinates x, y"""
pos = 0
i = 0
while i < y:
prompt_len, character_widths = self.screeninfo[i]
offset = len(character_widths) - character_widths.count(0)
in_wrapped_line = prompt_len + sum(character_widths) >= self.console.width
if in_wrapped_line:
pos += offset - 1 # -1 cause backslash is not in buffer
else:
pos += offset + 1 # +1 cause newline is in buffer
i += 1
j = 0
cur_x = self.screeninfo[i][0]
while cur_x < x:
if self.screeninfo[i][1][j] == 0:
continue
cur_x += self.screeninfo[i][1][j]
j += 1
pos += 1
self.pos = pos
def pos2xy(self) -> tuple[int, int]:
"""Return the x, y coordinates of position 'pos'."""
# this *is* incomprehensible, yes.
y = 0
pos = self.pos
assert 0 <= pos <= len(self.buffer)
if pos == len(self.buffer):
y = len(self.screeninfo) - 1
p, l2 = self.screeninfo[y]
return p + sum(l2) + l2.count(0), y
for p, l2 in self.screeninfo:
l = len(l2) - l2.count(0)
in_wrapped_line = p + sum(l2) >= self.console.width
offset = l - 1 if in_wrapped_line else l # need to remove backslash
if offset >= pos:
break
else:
if p + sum(l2) >= self.console.width:
pos -= l - 1 # -1 cause backslash is not in buffer
else:
pos -= l + 1 # +1 cause newline is in buffer
y += 1
return p + sum(l2[:pos]), y
def insert(self, text: str | list[str]) -> None:
"""Insert 'text' at the insertion point."""
self.buffer[self.pos : self.pos] = list(text)
self.pos += len(text)
self.dirty = True
def update_cursor(self) -> None:
"""Move the cursor to reflect changes in self.pos"""
self.cxy = self.pos2xy()
self.console.move_cursor(*self.cxy)
def after_command(self, cmd: Command) -> None:
"""This function is called to allow post command cleanup."""
if getattr(cmd, "kills_digit_arg", True):
if self.arg is not None:
self.dirty = True
self.arg = None
def prepare(self) -> None:
"""Get ready to run. Call restore when finished. You must not
write to the console in between the calls to prepare and
restore."""
try:
self.console.prepare()
self.arg = None
self.finished = False
del self.buffer[:]
self.pos = 0
self.dirty = True
self.last_command = None
self.calc_screen()
except BaseException:
self.restore()
raise
def last_command_is(self, cls: type) -> bool:
if not self.last_command:
return False
return issubclass(cls, self.last_command)
def restore(self) -> None:
"""Clean up after a run."""
self.console.restore()
@contextmanager
def suspend(self) -> SimpleContextManager:
"""A context manager to delegate to another reader."""
prev_state = {f.name: getattr(self, f.name) for f in fields(self)}
try:
self.restore()
yield
finally:
for arg in ("msg", "ps1", "ps2", "ps3", "ps4", "paste_mode"):
setattr(self, arg, prev_state[arg])
self.prepare()
pass
def finish(self) -> None:
"""Called when a command signals that we're finished."""
pass
def error(self, msg: str = "none") -> None:
self.msg = "! " + msg + " "
self.dirty = True
self.console.beep()
def update_screen(self) -> None:
if self.dirty:
self.refresh()
def refresh(self) -> None:
"""Recalculate and refresh the screen."""
# this call sets up self.cxy, so call it first.
self.screen = self.calc_screen()
self.console.refresh(self.screen, self.cxy)
self.dirty = False
def do_cmd(self, cmd: tuple[str, list[str]]) -> None:
"""`cmd` is a tuple of "event_name" and "event", which in the current
implementation is always just the "buffer" which happens to be a list
of single-character strings."""
trace("received command {cmd}", cmd=cmd)
if isinstance(cmd[0], str):
command_type = self.commands.get(cmd[0], commands.invalid_command)
elif isinstance(cmd[0], type):
command_type = cmd[0]
else:
return # nothing to do
command = command_type(self, *cmd) # type: ignore[arg-type]
command.do()
self.after_command(command)
if self.dirty and not self.in_bracketed_paste:
self.refresh()
else:
self.update_cursor()
if not isinstance(cmd, commands.digit_arg):
self.last_command = command_type
self.finished = bool(command.finish)
if self.finished:
self.console.finish()
self.finish()
def handle1(self, block: bool = True) -> bool:
"""Handle a single event. Wait as long as it takes if block
is true (the default), otherwise return False if no event is
pending."""
if self.msg:
self.msg = ""
self.dirty = True
while True:
event = self.console.get_event(block)
if not event: # can only happen if we're not blocking
return False
translate = True
if event.evt == "key":
self.input_trans.push(event)
elif event.evt == "scroll":
self.refresh()
elif event.evt == "resize":
self.refresh()
else:
translate = False
if translate:
cmd = self.input_trans.get()
else:
cmd = [event.evt, event.data]
if cmd is None:
if block:
continue
else:
return False
self.do_cmd(cmd)
return True
def push_char(self, char: int | bytes) -> None:
self.console.push_char(char)
self.handle1(block=False)
def readline(self, startup_hook: Callback | None = None) -> str:
"""Read a line. The implementation of this method also shows
how to drive Reader if you want more control over the event
loop."""
self.prepare()
try:
if startup_hook is not None:
startup_hook()
self.refresh()
while not self.finished:
self.handle1()
return self.get_unicode()
finally:
self.restore()
def bind(self, spec: KeySpec, command: CommandName) -> None:
self.keymap = self.keymap + ((spec, command),)
self.input_trans = input.KeymapTranslator(
self.keymap, invalid_cls="invalid-key", character_cls="self-insert"
)
def get_unicode(self) -> str:
"""Return the current buffer as a unicode string."""
return "".join(self.buffer)
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