|
| 1 | +"""Utilities needed to emulate Python's interactive interpreter. |
| 2 | +
|
| 3 | +""" |
| 4 | + |
| 5 | +# Inspired by similar code by Jeff Epler and Fredrik Lundh. |
| 6 | + |
| 7 | + |
| 8 | +import sys |
| 9 | +import traceback |
| 10 | +from codeop import CommandCompiler, compile_command |
| 11 | + |
| 12 | +__all__ = ["InteractiveInterpreter", "InteractiveConsole", "interact", |
| 13 | + "compile_command"] |
| 14 | + |
| 15 | +class InteractiveInterpreter: |
| 16 | + """Base class for InteractiveConsole. |
| 17 | +
|
| 18 | + This class deals with parsing and interpreter state (the user's |
| 19 | + namespace); it doesn't deal with input buffering or prompting or |
| 20 | + input file naming (the filename is always passed in explicitly). |
| 21 | +
|
| 22 | + """ |
| 23 | + |
| 24 | + def __init__(self, locals=None): |
| 25 | + """Constructor. |
| 26 | +
|
| 27 | + The optional 'locals' argument specifies the dictionary in |
| 28 | + which code will be executed; it defaults to a newly created |
| 29 | + dictionary with key "__name__" set to "__console__" and key |
| 30 | + "__doc__" set to None. |
| 31 | +
|
| 32 | + """ |
| 33 | + if locals is None: |
| 34 | + locals = {"__name__": "__console__", "__doc__": None} |
| 35 | + self.locals = locals |
| 36 | + self.compile = CommandCompiler() |
| 37 | + |
| 38 | + def runsource(self, source, filename="<input>", symbol="single"): |
| 39 | + """Compile and run some source in the interpreter. |
| 40 | +
|
| 41 | + Arguments are as for compile_command(). |
| 42 | +
|
| 43 | + One of several things can happen: |
| 44 | +
|
| 45 | + 1) The input is incorrect; compile_command() raised an |
| 46 | + exception (SyntaxError or OverflowError). A syntax traceback |
| 47 | + will be printed by calling the showsyntaxerror() method. |
| 48 | +
|
| 49 | + 2) The input is incomplete, and more input is required; |
| 50 | + compile_command() returned None. Nothing happens. |
| 51 | +
|
| 52 | + 3) The input is complete; compile_command() returned a code |
| 53 | + object. The code is executed by calling self.runcode() (which |
| 54 | + also handles run-time exceptions, except for SystemExit). |
| 55 | +
|
| 56 | + The return value is True in case 2, False in the other cases (unless |
| 57 | + an exception is raised). The return value can be used to |
| 58 | + decide whether to use sys.ps1 or sys.ps2 to prompt the next |
| 59 | + line. |
| 60 | +
|
| 61 | + """ |
| 62 | + try: |
| 63 | + code = self.compile(source, filename, symbol) |
| 64 | + except (OverflowError, SyntaxError, ValueError): |
| 65 | + # Case 1 |
| 66 | + self.showsyntaxerror(filename) |
| 67 | + return False |
| 68 | + |
| 69 | + if code is None: |
| 70 | + # Case 2 |
| 71 | + return True |
| 72 | + |
| 73 | + # Case 3 |
| 74 | + self.runcode(code) |
| 75 | + return False |
| 76 | + |
| 77 | + def runcode(self, code): |
| 78 | + """Execute a code object. |
| 79 | +
|
| 80 | + When an exception occurs, self.showtraceback() is called to |
| 81 | + display a traceback. All exceptions are caught except |
| 82 | + SystemExit, which is reraised. |
| 83 | +
|
| 84 | + A note about KeyboardInterrupt: this exception may occur |
| 85 | + elsewhere in this code, and may not always be caught. The |
| 86 | + caller should be prepared to deal with it. |
| 87 | +
|
| 88 | + """ |
| 89 | + try: |
| 90 | + exec(code, self.locals) |
| 91 | + except SystemExit: |
| 92 | + raise |
| 93 | + except: |
| 94 | + self.showtraceback() |
| 95 | + |
| 96 | + def showsyntaxerror(self, filename=None): |
| 97 | + """Display the syntax error that just occurred. |
| 98 | +
|
| 99 | + This doesn't display a stack trace because there isn't one. |
| 100 | +
|
| 101 | + If a filename is given, it is stuffed in the exception instead |
| 102 | + of what was there before (because Python's parser always uses |
| 103 | + "<string>" when reading from a string). |
| 104 | +
|
| 105 | + The output is written by self.write(), below. |
| 106 | +
|
| 107 | + """ |
| 108 | + type, value, tb = sys.exc_info() |
| 109 | + sys.last_type = type |
| 110 | + sys.last_value = value |
| 111 | + sys.last_traceback = tb |
| 112 | + if filename and type is SyntaxError: |
| 113 | + # Work hard to stuff the correct filename in the exception |
| 114 | + try: |
| 115 | + msg, (dummy_filename, lineno, offset, line) = value.args |
| 116 | + except ValueError: |
| 117 | + # Not the format we expect; leave it alone |
| 118 | + pass |
| 119 | + else: |
| 120 | + # Stuff in the right filename |
| 121 | + value = SyntaxError(msg, (filename, lineno, offset, line)) |
| 122 | + sys.last_value = value |
| 123 | + if sys.excepthook is sys.__excepthook__: |
| 124 | + lines = traceback.format_exception_only(type, value) |
| 125 | + self.write(''.join(lines)) |
| 126 | + else: |
| 127 | + # If someone has set sys.excepthook, we let that take precedence |
| 128 | + # over self.write |
| 129 | + sys.excepthook(type, value, tb) |
| 130 | + |
| 131 | + def showtraceback(self): |
| 132 | + """Display the exception that just occurred. |
| 133 | +
|
| 134 | + We remove the first stack item because it is our own code. |
| 135 | +
|
| 136 | + The output is written by self.write(), below. |
| 137 | +
|
| 138 | + """ |
| 139 | + sys.last_type, sys.last_value, last_tb = ei = sys.exc_info() |
| 140 | + sys.last_traceback = last_tb |
| 141 | + try: |
| 142 | + lines = traceback.format_exception(ei[0], ei[1], last_tb.tb_next) |
| 143 | + if sys.excepthook is sys.__excepthook__: |
| 144 | + self.write(''.join(lines)) |
| 145 | + else: |
| 146 | + # If someone has set sys.excepthook, we let that take precedence |
| 147 | + # over self.write |
| 148 | + sys.excepthook(ei[0], ei[1], last_tb) |
| 149 | + finally: |
| 150 | + last_tb = ei = None |
| 151 | + |
| 152 | + def write(self, data): |
| 153 | + """Write a string. |
| 154 | +
|
| 155 | + The base implementation writes to sys.stderr; a subclass may |
| 156 | + replace this with a different implementation. |
| 157 | +
|
| 158 | + """ |
| 159 | + sys.stderr.write(data) |
| 160 | + |
| 161 | + |
| 162 | +class InteractiveConsole(InteractiveInterpreter): |
| 163 | + """Closely emulate the behavior of the interactive Python interpreter. |
| 164 | +
|
| 165 | + This class builds on InteractiveInterpreter and adds prompting |
| 166 | + using the familiar sys.ps1 and sys.ps2, and input buffering. |
| 167 | +
|
| 168 | + """ |
| 169 | + |
| 170 | + def __init__(self, locals=None, filename="<console>"): |
| 171 | + """Constructor. |
| 172 | +
|
| 173 | + The optional locals argument will be passed to the |
| 174 | + InteractiveInterpreter base class. |
| 175 | +
|
| 176 | + The optional filename argument should specify the (file)name |
| 177 | + of the input stream; it will show up in tracebacks. |
| 178 | +
|
| 179 | + """ |
| 180 | + InteractiveInterpreter.__init__(self, locals) |
| 181 | + self.filename = filename |
| 182 | + self.resetbuffer() |
| 183 | + |
| 184 | + def resetbuffer(self): |
| 185 | + """Reset the input buffer.""" |
| 186 | + self.buffer = [] |
| 187 | + |
| 188 | + def interact(self, banner=None, exitmsg=None): |
| 189 | + """Closely emulate the interactive Python console. |
| 190 | +
|
| 191 | + The optional banner argument specifies the banner to print |
| 192 | + before the first interaction; by default it prints a banner |
| 193 | + similar to the one printed by the real Python interpreter, |
| 194 | + followed by the current class name in parentheses (so as not |
| 195 | + to confuse this with the real interpreter -- since it's so |
| 196 | + close!). |
| 197 | +
|
| 198 | + The optional exitmsg argument specifies the exit message |
| 199 | + printed when exiting. Pass the empty string to suppress |
| 200 | + printing an exit message. If exitmsg is not given or None, |
| 201 | + a default message is printed. |
| 202 | +
|
| 203 | + """ |
| 204 | + try: |
| 205 | + sys.ps1 |
| 206 | + except AttributeError: |
| 207 | + sys.ps1 = ">>> " |
| 208 | + try: |
| 209 | + sys.ps2 |
| 210 | + except AttributeError: |
| 211 | + sys.ps2 = "... " |
| 212 | + cprt = 'Type "help", "copyright", "credits" or "license" for more information.' |
| 213 | + if banner is None: |
| 214 | + self.write("Python %s on %s\n%s\n(%s)\n" % |
| 215 | + (sys.version, sys.platform, cprt, |
| 216 | + self.__class__.__name__)) |
| 217 | + elif banner: |
| 218 | + self.write("%s\n" % str(banner)) |
| 219 | + more = 0 |
| 220 | + while 1: |
| 221 | + try: |
| 222 | + if more: |
| 223 | + prompt = sys.ps2 |
| 224 | + else: |
| 225 | + prompt = sys.ps1 |
| 226 | + try: |
| 227 | + line = self.raw_input(prompt) |
| 228 | + except EOFError: |
| 229 | + self.write("\n") |
| 230 | + break |
| 231 | + else: |
| 232 | + more = self.push(line) |
| 233 | + except KeyboardInterrupt: |
| 234 | + self.write("\nKeyboardInterrupt\n") |
| 235 | + self.resetbuffer() |
| 236 | + more = 0 |
| 237 | + if exitmsg is None: |
| 238 | + self.write('now exiting %s...\n' % self.__class__.__name__) |
| 239 | + elif exitmsg != '': |
| 240 | + self.write('%s\n' % exitmsg) |
| 241 | + |
| 242 | + def push(self, line): |
| 243 | + """Push a line to the interpreter. |
| 244 | +
|
| 245 | + The line should not have a trailing newline; it may have |
| 246 | + internal newlines. The line is appended to a buffer and the |
| 247 | + interpreter's runsource() method is called with the |
| 248 | + concatenated contents of the buffer as source. If this |
| 249 | + indicates that the command was executed or invalid, the buffer |
| 250 | + is reset; otherwise, the command is incomplete, and the buffer |
| 251 | + is left as it was after the line was appended. The return |
| 252 | + value is 1 if more input is required, 0 if the line was dealt |
| 253 | + with in some way (this is the same as runsource()). |
| 254 | +
|
| 255 | + """ |
| 256 | + self.buffer.append(line) |
| 257 | + source = "\n".join(self.buffer) |
| 258 | + more = self.runsource(source, self.filename) |
| 259 | + if not more: |
| 260 | + self.resetbuffer() |
| 261 | + return more |
| 262 | + |
| 263 | + def raw_input(self, prompt=""): |
| 264 | + """Write a prompt and read a line. |
| 265 | +
|
| 266 | + The returned line does not include the trailing newline. |
| 267 | + When the user enters the EOF key sequence, EOFError is raised. |
| 268 | +
|
| 269 | + The base implementation uses the built-in function |
| 270 | + input(); a subclass may replace this with a different |
| 271 | + implementation. |
| 272 | +
|
| 273 | + """ |
| 274 | + return input(prompt) |
| 275 | + |
| 276 | + |
| 277 | + |
| 278 | +def interact(banner=None, readfunc=None, local=None, exitmsg=None): |
| 279 | + """Closely emulate the interactive Python interpreter. |
| 280 | +
|
| 281 | + This is a backwards compatible interface to the InteractiveConsole |
| 282 | + class. When readfunc is not specified, it attempts to import the |
| 283 | + readline module to enable GNU readline if it is available. |
| 284 | +
|
| 285 | + Arguments (all optional, all default to None): |
| 286 | +
|
| 287 | + banner -- passed to InteractiveConsole.interact() |
| 288 | + readfunc -- if not None, replaces InteractiveConsole.raw_input() |
| 289 | + local -- passed to InteractiveInterpreter.__init__() |
| 290 | + exitmsg -- passed to InteractiveConsole.interact() |
| 291 | +
|
| 292 | + """ |
| 293 | + console = InteractiveConsole(local) |
| 294 | + if readfunc is not None: |
| 295 | + console.raw_input = readfunc |
| 296 | + else: |
| 297 | + try: |
| 298 | + import readline |
| 299 | + except ImportError: |
| 300 | + pass |
| 301 | + console.interact(banner, exitmsg) |
| 302 | + |
| 303 | + |
| 304 | +if __name__ == "__main__": |
| 305 | + import argparse |
| 306 | + |
| 307 | + parser = argparse.ArgumentParser() |
| 308 | + parser.add_argument('-q', action='store_true', |
| 309 | + help="don't print version and copyright messages") |
| 310 | + args = parser.parse_args() |
| 311 | + if args.q or sys.flags.quiet: |
| 312 | + banner = '' |
| 313 | + else: |
| 314 | + banner = None |
| 315 | + interact(banner) |
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