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Guido van Rossum5d42b5b1998-10-22 21:56:44 +00001"""Utilities needed to emulate Python's interactive interpreter.
Guido van Rossum5227f0f1998-09-22 20:38:53 +00002
Guido van Rossum5227f0f1998-09-22 20:38:53 +00003"""
Guido van Rossum1557a731997-07-18 16:57:52 +00004
Guido van Rossum98d9fd32000-02-28 15:12:25 +00005# Inspired by similar code by Jeff Epler and Fredrik Lundh.
6
Guido van Rossum5d42b5b1998-10-22 21:56:44 +00007
Guido van Rossuma93b8481998-06-23 19:31:19 +00008import sys
Guido van Rossuma93b8481998-06-23 19:31:19 +00009import traceback
Tim Peters6cd6a822001-08-17 22:11:27 +000010from codeop import CommandCompiler, compile_command
Guido van Rossum90981e01997-10-07 14:47:24 +000011
Tim Peters6cd6a822001-08-17 22:11:27 +000012__all__ = ["InteractiveInterpreter", "InteractiveConsole", "interact",
Skip Montanaroe99d5ea2001-01-20 19:54:20 +000013 "compile_command"]
14
Guido van Rossum4ec59c72001-01-13 22:10:41 +000015def softspace(file, newvalue):
16 oldvalue = 0
17 try:
18 oldvalue = file.softspace
19 except AttributeError:
20 pass
21 try:
22 file.softspace = newvalue
Guido van Rossum555d12f2001-09-18 13:33:01 +000023 except (AttributeError, TypeError):
24 # "attribute-less object" or "read-only attributes"
Guido van Rossum4ec59c72001-01-13 22:10:41 +000025 pass
26 return oldvalue
Guido van Rossum90981e01997-10-07 14:47:24 +000027
Guido van Rossum5227f0f1998-09-22 20:38:53 +000028class InteractiveInterpreter:
29 """Base class for InteractiveConsole.
Guido van Rossuma93b8481998-06-23 19:31:19 +000030
Guido van Rossum5227f0f1998-09-22 20:38:53 +000031 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
Guido van Rossuma93b8481998-06-23 19:31:19 +000035 """
36
Guido van Rossum5227f0f1998-09-22 20:38:53 +000037 def __init__(self, locals=None):
Guido van Rossuma93b8481998-06-23 19:31:19 +000038 """Constructor.
39
Guido van Rossum5227f0f1998-09-22 20:38:53 +000040 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.
Guido van Rossuma93b8481998-06-23 19:31:19 +000044
45 """
Guido van Rossuma93b8481998-06-23 19:31:19 +000046 if locals is None:
Guido van Rossum5227f0f1998-09-22 20:38:53 +000047 locals = {"__name__": "__console__", "__doc__": None}
Guido van Rossuma93b8481998-06-23 19:31:19 +000048 self.locals = locals
Tim Peters6cd6a822001-08-17 22:11:27 +000049 self.compile = CommandCompiler()
Guido van Rossum5227f0f1998-09-22 20:38:53 +000050
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
Tim Petersbc0e9102002-04-04 22:55:58 +000069 The return value is True in case 2, False in the other cases (unless
Guido van Rossum5227f0f1998-09-22 20:38:53 +000070 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:
Tim Peters6cd6a822001-08-17 22:11:27 +000076 code = self.compile(source, filename, symbol)
Guido van Rossum48450cf2001-01-15 18:13:35 +000077 except (OverflowError, SyntaxError, ValueError):
Guido van Rossum5227f0f1998-09-22 20:38:53 +000078 # Case 1
79 self.showsyntaxerror(filename)
Tim Petersbc0e9102002-04-04 22:55:58 +000080 return False
Guido van Rossum5227f0f1998-09-22 20:38:53 +000081
82 if code is None:
83 # Case 2
Tim Petersbc0e9102002-04-04 22:55:58 +000084 return True
Guido van Rossum5227f0f1998-09-22 20:38:53 +000085
86 # Case 3
87 self.runcode(code)
Tim Petersbc0e9102002-04-04 22:55:58 +000088 return False
Guido van Rossum5227f0f1998-09-22 20:38:53 +000089
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()
Guido van Rossum4ec59c72001-01-13 22:10:41 +0000108 else:
109 if softspace(sys.stdout, 0):
110 print
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000111
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
Skip Montanaro0679a732002-03-25 21:44:07 +0000136 value = SyntaxError(msg, (filename, lineno, offset, line))
Fred Drakec7745d42001-05-03 04:58:49 +0000137 sys.last_value = value
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000138 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:
Guido van Rossum7dd06962000-12-27 19:12:58 +0000158 list.insert(0, "Traceback (most recent call last):\n")
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000159 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
174class 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
Guido van Rossuma93b8481998-06-23 19:31:19 +0000194 self.resetbuffer()
195
196 def resetbuffer(self):
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000197 """Reset the input buffer."""
Guido van Rossuma93b8481998-06-23 19:31:19 +0000198 self.buffer = []
199
200 def interact(self, banner=None):
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000201 """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 """
Guido van Rossuma93b8481998-06-23 19:31:19 +0000211 try:
212 sys.ps1
213 except AttributeError:
214 sys.ps1 = ">>> "
215 try:
216 sys.ps2
217 except AttributeError:
218 sys.ps2 = "... "
Skip Montanaroacb29ae2002-03-25 22:04:23 +0000219 cprt = 'Type "help", "copyright", "credits" or "license" for more information.'
Guido van Rossuma93b8481998-06-23 19:31:19 +0000220 if banner is None:
221 self.write("Python %s on %s\n%s\n(%s)\n" %
Guido van Rossumc5f15b02001-01-14 23:04:22 +0000222 (sys.version, sys.platform, cprt,
Guido van Rossuma93b8481998-06-23 19:31:19 +0000223 self.__class__.__name__))
Guido van Rossum45e2fbc1998-03-26 21:13:24 +0000224 else:
Guido van Rossuma93b8481998-06-23 19:31:19 +0000225 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
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000248 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()).
Guido van Rossuma93b8481998-06-23 19:31:19 +0000257
258 """
259 self.buffer.append(line)
Eric S. Raymond6b71e742001-02-09 08:56:30 +0000260 source = "\n".join(self.buffer)
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000261 more = self.runsource(source, self.filename)
262 if not more:
Guido van Rossuma93b8481998-06-23 19:31:19 +0000263 self.resetbuffer()
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000264 return more
Guido van Rossuma93b8481998-06-23 19:31:19 +0000265
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
Neal Norwitzce96f692006-03-17 06:49:51 +0000272 The base implementation uses sys.stdin.readline(); a subclass
273 may replace this with a different implementation.
Guido van Rossuma93b8481998-06-23 19:31:19 +0000274
275 """
Neal Norwitzce96f692006-03-17 06:49:51 +0000276 sys.stdout.write(prompt)
277 sys.stdout.flush()
278 return sys.stdin.readline()
279
Guido van Rossuma93b8481998-06-23 19:31:19 +0000280
281
Guido van Rossumd90ae191998-10-19 18:42:53 +0000282def interact(banner=None, readfunc=None, local=None):
Guido van Rossuma93b8481998-06-23 19:31:19 +0000283 """Closely emulate the interactive Python interpreter.
284
285 This is a backwards compatible interface to the InteractiveConsole
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000286 class. When readfunc is not specified, it attempts to import the
287 readline module to enable GNU readline if it is available.
Guido van Rossuma93b8481998-06-23 19:31:19 +0000288
289 Arguments (all optional, all default to None):
290
291 banner -- passed to InteractiveConsole.interact()
292 readfunc -- if not None, replaces InteractiveConsole.raw_input()
Guido van Rossumd90ae191998-10-19 18:42:53 +0000293 local -- passed to InteractiveInterpreter.__init__()
Guido van Rossuma93b8481998-06-23 19:31:19 +0000294
295 """
Guido van Rossumd90ae191998-10-19 18:42:53 +0000296 console = InteractiveConsole(local)
Guido van Rossuma93b8481998-06-23 19:31:19 +0000297 if readfunc is not None:
298 console.raw_input = readfunc
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000299 else:
300 try:
301 import readline
Skip Montanaro0679a732002-03-25 21:44:07 +0000302 except ImportError:
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000303 pass
Guido van Rossuma93b8481998-06-23 19:31:19 +0000304 console.interact(banner)
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000305
306
Guido van Rossum90981e01997-10-07 14:47:24 +0000307if __name__ == '__main__':
Guido van Rossum4b499dd32003-02-13 22:07:59 +0000308 import pdb
309 pdb.run("interact()\n")