cpython/Lib/code.py

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"""Utilities needed to emulate Python's interactive interpreter.
"""
# Inspired by similar code by Jeff Epler and Fredrik Lundh.
import sys
import traceback
from codeop import CommandCompiler, compile_command
__all__ = ["InteractiveInterpreter", "InteractiveConsole", "interact",
"compile_command"]
class InteractiveInterpreter:
"""Base class for InteractiveConsole.
This class deals with parsing and interpreter state (the user's
namespace); it doesn't deal with input buffering or prompting or
input file naming (the filename is always passed in explicitly).
"""
def __init__(self, locals=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 "__console__" and key
"__doc__" set to None.
"""
if locals is None:
locals = {"__name__": "__console__", "__doc__": None}
self.locals = locals
self.compile = CommandCompiler()
def runsource(self, source, filename="<input>", symbol="single"):
"""Compile and run some source in the interpreter.
Arguments are as for compile_command().
One of several things can happen:
1) The input is incorrect; compile_command() raised an
exception (SyntaxError or OverflowError). A syntax traceback
will be printed by calling the showsyntaxerror() method.
2) The input is incomplete, and more input is required;
compile_command() returned None. Nothing happens.
3) The input is complete; compile_command() returned a code
object. The code is executed by calling self.runcode() (which
also handles run-time exceptions, except for SystemExit).
The return value is True in case 2, False in the other cases (unless
an exception is raised). The return value can be used to
decide whether to use sys.ps1 or sys.ps2 to prompt the next
line.
"""
try:
code = self.compile(source, filename, symbol)
except (OverflowError, SyntaxError, ValueError):
# Case 1
self.showsyntaxerror(filename)
return False
if code is None:
# Case 2
return True
# Case 3
self.runcode(code)
return False
def runcode(self, code):
"""Execute a code object.
When an exception occurs, self.showtraceback() is called to
display a traceback. All exceptions are caught except
SystemExit, which is reraised.
A note about KeyboardInterrupt: this exception may occur
elsewhere in this code, and may not always be caught. The
caller should be prepared to deal with it.
"""
try:
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exec(code, self.locals)
except SystemExit:
raise
except:
self.showtraceback()
def showsyntaxerror(self, filename=None):
"""Display the syntax error that just occurred.
This doesn't display a stack trace because there isn't one.
If a filename is given, it is stuffed in the exception instead
of what was there before (because Python's parser always uses
"<string>" when reading from a string).
The output is written by self.write(), below.
"""
type, value, tb = sys.exc_info()
sys.last_exc = value
sys.last_type = type
sys.last_value = value
sys.last_traceback = tb
if filename and type is SyntaxError:
# Work hard to stuff the correct filename in the exception
try:
Merged revisions 56492-56752 via svnmerge from svn+ssh://pythondev@svn.python.org/python/branches/p3yk ........ r56497 | kurt.kaiser | 2007-07-22 14:55:16 -0700 (Sun, 22 Jul 2007) | 4 lines In the case of syntax errors, in py3k format_exception_only() was including line number and position in the final line of the exception notification, duplicating info in previous lines. ........ r56501 | kurt.kaiser | 2007-07-22 19:35:50 -0700 (Sun, 22 Jul 2007) | 2 lines Hum, needed a newline in the last change. ........ r56536 | kurt.kaiser | 2007-07-24 19:06:48 -0700 (Tue, 24 Jul 2007) | 5 lines Not all instantiations of SyntaxError set the args attribute. e.g. symtable.c Modify format_exception_only() to get SyntaxError attributes directly instead of unpacking 'args'. ........ r56537 | kurt.kaiser | 2007-07-24 19:13:03 -0700 (Tue, 24 Jul 2007) | 3 lines Update doctest strings: traceback.py no longer prints redundant location information in the last line of the exception display. ........ r56627 | kurt.kaiser | 2007-07-29 21:06:57 -0700 (Sun, 29 Jul 2007) | 2 lines Interactive interpreter emulator (code.py) failing to print exceptions. ........ r56628 | kurt.kaiser | 2007-07-29 21:41:02 -0700 (Sun, 29 Jul 2007) | 2 lines Eliminate extra lines before and after tracebacks. ........ r56638 | kurt.kaiser | 2007-07-31 19:36:45 -0700 (Tue, 31 Jul 2007) | 3 lines Refactor syntax error display in shell and edit windows; move colorize_syntax_error() to EditorWindow; update to py3k. ........ r56685 | neal.norwitz | 2007-08-02 22:20:23 -0700 (Thu, 02 Aug 2007) | 10 lines Remove several h/w and o/s specific modules that are undocumented, obsolete, and/or not widely used: linuxaudiodev.c, sunaudiodev.c Lib/plat-sunos5/SUNAUDIODEV.py Lib/audiodev.py Tools/audiopy/audiopy Move Lib/toaiff.py to Demo. See PEP 3108 for most of the details. ........ r56686 | neal.norwitz | 2007-08-02 22:21:48 -0700 (Thu, 02 Aug 2007) | 4 lines Missed one module that should have been removed since it relied on audiodev which was removed. ........ r56748 | neal.norwitz | 2007-08-04 19:19:04 -0700 (Sat, 04 Aug 2007) | 1 line Make from X import * outside module scope an error. ........ r56750 | neal.norwitz | 2007-08-04 19:35:01 -0700 (Sat, 04 Aug 2007) | 1 line Use READONLY consistently instead of RO ........
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msg, (dummy_filename, lineno, offset, line) = value.args
except ValueError:
# Not the format we expect; leave it alone
pass
else:
# Stuff in the right filename
value = SyntaxError(msg, (filename, lineno, offset, line))
sys.last_exc = sys.last_value = value
if sys.excepthook is sys.__excepthook__:
lines = traceback.format_exception_only(type, value)
self.write(''.join(lines))
else:
# If someone has set sys.excepthook, we let that take precedence
# over self.write
sys.excepthook(type, value, tb)
def showtraceback(self):
"""Display the exception that just occurred.
We remove the first stack item because it is our own code.
The output is written by self.write(), below.
"""
sys.last_type, sys.last_value, last_tb = ei = sys.exc_info()
sys.last_traceback = last_tb
sys.last_exc = ei[1]
try:
lines = traceback.format_exception(ei[0], ei[1], last_tb.tb_next)
if sys.excepthook is sys.__excepthook__:
self.write(''.join(lines))
else:
# If someone has set sys.excepthook, we let that take precedence
# over self.write
sys.excepthook(ei[0], ei[1], last_tb)
finally:
last_tb = ei = None
def write(self, data):
"""Write a string.
The base implementation writes to sys.stderr; a subclass may
replace this with a different implementation.
"""
sys.stderr.write(data)
class InteractiveConsole(InteractiveInterpreter):
"""Closely emulate the behavior of the interactive Python interpreter.
This class builds on InteractiveInterpreter and adds prompting
using the familiar sys.ps1 and sys.ps2, and input buffering.
"""
def __init__(self, locals=None, filename="<console>"):
"""Constructor.
The optional locals argument will be passed to the
InteractiveInterpreter base class.
The optional filename argument should specify the (file)name
of the input stream; it will show up in tracebacks.
"""
InteractiveInterpreter.__init__(self, locals)
self.filename = filename
self.resetbuffer()
def resetbuffer(self):
"""Reset the input buffer."""
self.buffer = []
def interact(self, banner=None, exitmsg=None):
"""Closely emulate the interactive Python console.
Merged revisions 56492-56752 via svnmerge from svn+ssh://pythondev@svn.python.org/python/branches/p3yk ........ r56497 | kurt.kaiser | 2007-07-22 14:55:16 -0700 (Sun, 22 Jul 2007) | 4 lines In the case of syntax errors, in py3k format_exception_only() was including line number and position in the final line of the exception notification, duplicating info in previous lines. ........ r56501 | kurt.kaiser | 2007-07-22 19:35:50 -0700 (Sun, 22 Jul 2007) | 2 lines Hum, needed a newline in the last change. ........ r56536 | kurt.kaiser | 2007-07-24 19:06:48 -0700 (Tue, 24 Jul 2007) | 5 lines Not all instantiations of SyntaxError set the args attribute. e.g. symtable.c Modify format_exception_only() to get SyntaxError attributes directly instead of unpacking 'args'. ........ r56537 | kurt.kaiser | 2007-07-24 19:13:03 -0700 (Tue, 24 Jul 2007) | 3 lines Update doctest strings: traceback.py no longer prints redundant location information in the last line of the exception display. ........ r56627 | kurt.kaiser | 2007-07-29 21:06:57 -0700 (Sun, 29 Jul 2007) | 2 lines Interactive interpreter emulator (code.py) failing to print exceptions. ........ r56628 | kurt.kaiser | 2007-07-29 21:41:02 -0700 (Sun, 29 Jul 2007) | 2 lines Eliminate extra lines before and after tracebacks. ........ r56638 | kurt.kaiser | 2007-07-31 19:36:45 -0700 (Tue, 31 Jul 2007) | 3 lines Refactor syntax error display in shell and edit windows; move colorize_syntax_error() to EditorWindow; update to py3k. ........ r56685 | neal.norwitz | 2007-08-02 22:20:23 -0700 (Thu, 02 Aug 2007) | 10 lines Remove several h/w and o/s specific modules that are undocumented, obsolete, and/or not widely used: linuxaudiodev.c, sunaudiodev.c Lib/plat-sunos5/SUNAUDIODEV.py Lib/audiodev.py Tools/audiopy/audiopy Move Lib/toaiff.py to Demo. See PEP 3108 for most of the details. ........ r56686 | neal.norwitz | 2007-08-02 22:21:48 -0700 (Thu, 02 Aug 2007) | 4 lines Missed one module that should have been removed since it relied on audiodev which was removed. ........ r56748 | neal.norwitz | 2007-08-04 19:19:04 -0700 (Sat, 04 Aug 2007) | 1 line Make from X import * outside module scope an error. ........ r56750 | neal.norwitz | 2007-08-04 19:35:01 -0700 (Sat, 04 Aug 2007) | 1 line Use READONLY consistently instead of RO ........
2007-08-05 12:29:28 -03:00
The optional banner argument specifies the banner to print
before the first interaction; by default it prints a banner
similar to the one printed by the real Python interpreter,
followed by the current class name in parentheses (so as not
to confuse this with the real interpreter -- since it's so
close!).
The optional exitmsg argument specifies the exit message
printed when exiting. Pass the empty string to suppress
printing an exit message. If exitmsg is not given or None,
a default message is printed.
"""
try:
sys.ps1
except AttributeError:
sys.ps1 = ">>> "
try:
sys.ps2
except AttributeError:
sys.ps2 = "... "
cprt = 'Type "help", "copyright", "credits" or "license" for more information.'
if banner is None:
self.write("Python %s on %s\n%s\n(%s)\n" %
(sys.version, sys.platform, cprt,
self.__class__.__name__))
elif banner:
self.write("%s\n" % str(banner))
more = 0
while 1:
try:
if more:
prompt = sys.ps2
else:
prompt = sys.ps1
try:
line = self.raw_input(prompt)
except EOFError:
self.write("\n")
break
else:
more = self.push(line)
except KeyboardInterrupt:
self.write("\nKeyboardInterrupt\n")
self.resetbuffer()
more = 0
if exitmsg is None:
self.write('now exiting %s...\n' % self.__class__.__name__)
elif exitmsg != '':
self.write('%s\n' % exitmsg)
def push(self, line):
"""Push a line to the interpreter.
The line should not have a trailing newline; it may have
internal newlines. The line is appended to a buffer and the
interpreter's runsource() method is called with the
concatenated contents of the buffer as source. If this
indicates that the command was executed or invalid, the buffer
is reset; otherwise, the command is incomplete, and the buffer
is left as it was after the line was appended. The return
value is 1 if more input is required, 0 if the line was dealt
with in some way (this is the same as runsource()).
"""
self.buffer.append(line)
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source = "\n".join(self.buffer)
more = self.runsource(source, self.filename)
if not more:
self.resetbuffer()
return more
def raw_input(self, prompt=""):
"""Write a prompt and read a line.
The returned line does not include the trailing newline.
When the user enters the EOF key sequence, EOFError is raised.
The base implementation uses the built-in function
input(); a subclass may replace this with a different
implementation.
"""
return input(prompt)
def interact(banner=None, readfunc=None, local=None, exitmsg=None):
"""Closely emulate the interactive Python interpreter.
This is a backwards compatible interface to the InteractiveConsole
class. When readfunc is not specified, it attempts to import the
readline module to enable GNU readline if it is available.
Arguments (all optional, all default to None):
banner -- passed to InteractiveConsole.interact()
readfunc -- if not None, replaces InteractiveConsole.raw_input()
local -- passed to InteractiveInterpreter.__init__()
exitmsg -- passed to InteractiveConsole.interact()
"""
console = InteractiveConsole(local)
if readfunc is not None:
console.raw_input = readfunc
else:
try:
import readline
except ImportError:
pass
console.interact(banner, exitmsg)
Merged revisions 75264,75268,75293,75318,75391-75392,75436,75478,75971,76003,76058,76140-76141,76231,76380,76428-76429 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r75264 | andrew.kuchling | 2009-10-05 17:30:22 -0500 (Mon, 05 Oct 2009) | 1 line Add various items ........ r75268 | andrew.kuchling | 2009-10-05 17:45:39 -0500 (Mon, 05 Oct 2009) | 1 line Remove two notes ........ r75293 | kristjan.jonsson | 2009-10-09 09:32:19 -0500 (Fri, 09 Oct 2009) | 2 lines http://bugs.python.org/issue7029 a non-default timer wasn't actually used by the individual Tests. ........ r75318 | benjamin.peterson | 2009-10-10 16:15:58 -0500 (Sat, 10 Oct 2009) | 1 line remove script which uses long gone module ........ r75391 | andrew.kuchling | 2009-10-13 10:49:33 -0500 (Tue, 13 Oct 2009) | 1 line Link to PEP ........ r75392 | andrew.kuchling | 2009-10-13 11:11:49 -0500 (Tue, 13 Oct 2009) | 1 line Various link, textual, and markup fixes ........ r75436 | benjamin.peterson | 2009-10-15 10:39:15 -0500 (Thu, 15 Oct 2009) | 1 line don't need to mess up sys.path ........ r75478 | senthil.kumaran | 2009-10-17 20:58:45 -0500 (Sat, 17 Oct 2009) | 3 lines Fix a typo. ........ r75971 | benjamin.peterson | 2009-10-30 22:56:15 -0500 (Fri, 30 Oct 2009) | 1 line add some checks for evaluation order with parenthesis #7210 ........ r76003 | antoine.pitrou | 2009-10-31 19:30:13 -0500 (Sat, 31 Oct 2009) | 6 lines Hopefully fix the buildbot problems on test_mailbox, by computing the maildir toc cache refresh date before actually refreshing the cache. (see #6896) ........ r76058 | benjamin.peterson | 2009-11-02 10:14:19 -0600 (Mon, 02 Nov 2009) | 1 line grant list.index() a more informative error message #7252 ........ r76140 | nick.coghlan | 2009-11-07 02:13:55 -0600 (Sat, 07 Nov 2009) | 1 line Add test for runpy.run_module package execution and use something other than logging as the example of a non-executable package ........ r76141 | nick.coghlan | 2009-11-07 02:15:01 -0600 (Sat, 07 Nov 2009) | 1 line Some minor cleanups to private runpy code and docstrings ........ r76231 | benjamin.peterson | 2009-11-12 17:42:23 -0600 (Thu, 12 Nov 2009) | 1 line this main is much more useful ........ r76380 | antoine.pitrou | 2009-11-18 14:20:46 -0600 (Wed, 18 Nov 2009) | 3 lines Mention Giampolo R's new FTP TLS support in the what's new file ........ r76428 | benjamin.peterson | 2009-11-19 20:15:50 -0600 (Thu, 19 Nov 2009) | 1 line turn goto into do while loop ........ r76429 | benjamin.peterson | 2009-11-19 20:56:43 -0600 (Thu, 19 Nov 2009) | 2 lines avoid doing an uneeded import in a function ........
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if __name__ == "__main__":
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('-q', action='store_true',
help="don't print version and copyright messages")
args = parser.parse_args()
if args.q or sys.flags.quiet:
banner = ''
else:
banner = None
interact(banner)