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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: | |
| 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_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: | |
| 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_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 | |
| 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. | |
| 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) | |
| 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) | |
| 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) |