mirror of https://github.com/python/cpython
Subsume the interact() function in a class. This should make it
possible to use this in PythonWin, and to replace Fredrik Lundh's PythonInterpreter class. Fredrik is credited with the class' API.
This commit is contained in:
Guido van Rossum
parent
d9d2625dbd
commit
a93b848e33
241
Lib/code.py
241
Lib/code.py
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@ -1,5 +1,9 @@
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"""Utilities dealing with code objects."""
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import sys
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import string
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import traceback
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def compile_command(source, filename="<input>", symbol="single"):
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r"""Compile a command and determine whether it is incomplete.
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@ -60,51 +64,202 @@ def compile_command(source, filename="<input>", symbol="single"):
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raise SyntaxError, err1
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def interact(banner=None, readfunc=raw_input, local=None):
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# Due to Jeff Epler, with changes by Guido:
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"""Closely emulate the interactive Python console."""
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try: import readline # Enable GNU readline if available
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except: pass
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local = local or {}
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import sys, string, traceback
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sys.ps1 = '>>> '
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sys.ps2 = '... '
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if banner:
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print banner
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else:
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print "Python Interactive Console", sys.version
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print sys.copyright
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buf = []
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while 1:
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if buf: prompt = sys.ps2
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else: prompt = sys.ps1
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try: line = readfunc(prompt)
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except KeyboardInterrupt:
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print "\nKeyboardInterrupt"
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buf = []
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continue
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except EOFError: break
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buf.append(line)
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try: x = compile_command(string.join(buf, "\n"))
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except SyntaxError:
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traceback.print_exc(0)
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buf = []
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continue
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if x == None: continue
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class InteractiveConsole:
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"""Closely emulate the behavior of the interactive Python interpreter.
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After code by Jeff Epler and Fredrik Lundh.
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"""
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def __init__(self, filename="<console>", locals=None):
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"""Constructor.
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The optional filename argument specifies the (file)name of the
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input stream; it will show up in tracebacks. It defaults to
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'<console>'.
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"""
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self.filename = filename
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if locals is None:
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locals = {}
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self.locals = locals
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self.resetbuffer()
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def resetbuffer(self):
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"""Reset the input buffer (but not the variables!)."""
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self.buffer = []
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def interact(self, banner=None):
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"""Closely emulate the interactive Python console."""
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try:
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sys.ps1
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except AttributeError:
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sys.ps1 = ">>> "
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try:
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sys.ps2
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except AttributeError:
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sys.ps2 = "... "
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if banner is None:
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self.write("Python %s on %s\n%s\n(%s)\n" %
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(sys.version, sys.platform, sys.copyright,
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self.__class__.__name__))
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else:
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try: exec x in local
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self.write("%s\n" % str(banner))
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more = 0
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while 1:
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try:
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if more:
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prompt = sys.ps2
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else:
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prompt = sys.ps1
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try:
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line = self.raw_input(prompt)
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except EOFError:
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self.write("\n")
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break
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else:
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more = self.push(line)
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except KeyboardInterrupt:
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self.write("\nKeyboardInterrupt\n")
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self.resetbuffer()
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more = 0
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def push(self, line):
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"""Push a line to the interpreter.
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The line should not have a trailing newline.
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One of three things will happen:
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1) The input is incorrect; compile_command() raised
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SyntaxError. A syntax traceback will be printed.
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2) The input is incomplete, and more input is required;
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compile_command() returned None.
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3) The input is complete; compile_command() returned a code
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object. The code is executed. When an exception occurs, a
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traceback is printed. All exceptions are caught except
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SystemExit, which is reraised.
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The return value is 1 in case 2, 0 in the other cases. (The
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return value can be used to decide whether to use sys.ps1 or
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sys.ps2 to prompt the next line.)
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A note about KeyboardInterrupt: this exception may occur
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elsewhere in this code, and will not always be caught. The
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caller should be prepared to deal with it.
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"""
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self.buffer.append(line)
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try:
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x = compile_command(string.join(self.buffer, "\n"),
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filename=self.filename)
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except SyntaxError:
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# Case 1
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self.showsyntaxerror()
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self.resetbuffer()
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return 0
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if x is None:
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# Case 2
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return 1
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# Case 3
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try:
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exec x in self.locals
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except SystemExit:
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raise
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except:
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self.showtraceback()
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self.resetbuffer()
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return 0
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def showsyntaxerror(self):
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"""Display the syntax error that just occurred.
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This doesn't display a stack trace because there isn't one.
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The output is written by self.write(), below.
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"""
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type, value = sys.exc_info()[:2]
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# Work hard to stuff the correct filename in the exception
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try:
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msg, (filename, lineno, offset, line) = value
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except:
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pass
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else:
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try:
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value = SyntaxError(msg, (self.filename, lineno, offset, line))
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except:
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exc_type, exc_value, exc_traceback = \
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sys.exc_type, sys.exc_value, \
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sys.exc_traceback
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l = len(traceback.extract_tb(sys.exc_traceback))
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try: 1/0
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except:
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m = len(traceback.extract_tb(
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sys.exc_traceback))
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traceback.print_exception(exc_type,
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exc_value, exc_traceback, l-m)
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buf = []
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value = msg, (self.filename, lineno, offset, line)
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list = traceback.format_exception_only(type, value)
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map(self.write, list)
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def showtraceback(self):
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"""Display the exception that just occurred.
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We remove the first stack item because it is our own code.
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The output is written by self.write(), below.
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"""
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try:
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type, value, tb = sys.exc_info()
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tblist = traceback.extract_tb(tb)
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del tblist[0]
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list = traceback.format_list(tblist)
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list[len(list):] = traceback.format_exception_only(type, value)
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finally:
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tblist = tb = None
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map(self.write, list)
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def write(self, data):
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"""Write a string.
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The base implementation writes to sys.stderr; a subclass may
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replace this with a different implementation.
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"""
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sys.stderr.write(data)
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def raw_input(self, prompt=""):
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"""Write a prompt and read a line.
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The returned line does not include the trailing newline.
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When the user enters the EOF key sequence, EOFError is raised.
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The base implementation uses the built-in function
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raw_input(); a subclass may replace this with a different
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implementation.
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"""
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return raw_input(prompt)
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def interact(banner=None, readfunc=None, locals=None):
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"""Closely emulate the interactive Python interpreter.
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This is a backwards compatible interface to the InteractiveConsole
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class. It attempts to import the readline module to enable GNU
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readline if it is available.
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Arguments (all optional, all default to None):
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banner -- passed to InteractiveConsole.interact()
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readfunc -- if not None, replaces InteractiveConsole.raw_input()
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locals -- passed to InteractiveConsole.__init__()
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"""
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try:
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import readline
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except:
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pass
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console = InteractiveConsole(locals=locals)
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if readfunc is not None:
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console.raw_input = readfunc
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console.interact(banner)
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if __name__ == '__main__':
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interact()
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