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