Showing the changes to sys/lib/python/code.py (1 of 3706 files). Show all
Unified · Split
| @@ -0,0 +1,307 @@ | |||
| 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") | ||