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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 Rossum5227f0f1998-09-22 20:38:53 +000015class InteractiveInterpreter:
16 """Base class for InteractiveConsole.
Guido van Rossuma93b8481998-06-23 19:31:19 +000017
Guido van Rossum5227f0f1998-09-22 20:38:53 +000018 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
Guido van Rossuma93b8481998-06-23 19:31:19 +000022 """
23
Guido van Rossum5227f0f1998-09-22 20:38:53 +000024 def __init__(self, locals=None):
Guido van Rossuma93b8481998-06-23 19:31:19 +000025 """Constructor.
26
Guido van Rossum5227f0f1998-09-22 20:38:53 +000027 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.
Guido van Rossuma93b8481998-06-23 19:31:19 +000031
32 """
Guido van Rossuma93b8481998-06-23 19:31:19 +000033 if locals is None:
Guido van Rossum5227f0f1998-09-22 20:38:53 +000034 locals = {"__name__": "__console__", "__doc__": None}
Guido van Rossuma93b8481998-06-23 19:31:19 +000035 self.locals = locals
Tim Peters6cd6a822001-08-17 22:11:27 +000036 self.compile = CommandCompiler()
Guido van Rossum5227f0f1998-09-22 20:38:53 +000037
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 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
Tim Petersbc0e9102002-04-04 22:55:58 +000056 The return value is True in case 2, False in the other cases (unless
Guido van Rossum5227f0f1998-09-22 20:38:53 +000057 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:
Tim Peters6cd6a822001-08-17 22:11:27 +000063 code = self.compile(source, filename, symbol)
Guido van Rossum48450cf2001-01-15 18:13:35 +000064 except (OverflowError, SyntaxError, ValueError):
Guido van Rossum5227f0f1998-09-22 20:38:53 +000065 # Case 1
66 self.showsyntaxerror(filename)
Tim Petersbc0e9102002-04-04 22:55:58 +000067 return False
Guido van Rossum5227f0f1998-09-22 20:38:53 +000068
69 if code is None:
70 # Case 2
Tim Petersbc0e9102002-04-04 22:55:58 +000071 return True
Guido van Rossum5227f0f1998-09-22 20:38:53 +000072
73 # Case 3
74 self.runcode(code)
Tim Petersbc0e9102002-04-04 22:55:58 +000075 return False
Guido van Rossum5227f0f1998-09-22 20:38:53 +000076
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:
Georg Brandl7cae87c2006-09-06 06:51:57 +000090 exec(code, self.locals)
Guido van Rossum5227f0f1998-09-22 20:38:53 +000091 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, sys.last_traceback = sys.exc_info()
109 sys.last_type = type
110 sys.last_value = value
111 if filename and type is SyntaxError:
112 # Work hard to stuff the correct filename in the exception
113 try:
Guido van Rossum33d26892007-08-05 15:29:28 +0000114 msg, (dummy_filename, lineno, offset, line) = value.args
115 except ValueError:
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000116 # Not the format we expect; leave it alone
117 pass
118 else:
119 # Stuff in the right filename
Skip Montanaro0679a732002-03-25 21:44:07 +0000120 value = SyntaxError(msg, (filename, lineno, offset, line))
Fred Drakec7745d42001-05-03 04:58:49 +0000121 sys.last_value = value
Guido van Rossum33d26892007-08-05 15:29:28 +0000122 lines = traceback.format_exception_only(type, value)
123 self.write(''.join(lines))
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000124
125 def showtraceback(self):
126 """Display the exception that just occurred.
127
128 We remove the first stack item because it is our own code.
129
130 The output is written by self.write(), below.
131
132 """
133 try:
134 type, value, tb = sys.exc_info()
135 sys.last_type = type
136 sys.last_value = value
137 sys.last_traceback = tb
138 tblist = traceback.extract_tb(tb)
139 del tblist[:1]
Guido van Rossum33d26892007-08-05 15:29:28 +0000140 lines = traceback.format_list(tblist)
141 if lines:
142 lines.insert(0, "Traceback (most recent call last):\n")
143 lines.extend(traceback.format_exception_only(type, value))
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000144 finally:
145 tblist = tb = None
Guido van Rossum33d26892007-08-05 15:29:28 +0000146 self.write(''.join(lines))
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000147
148 def write(self, data):
149 """Write a string.
150
151 The base implementation writes to sys.stderr; a subclass may
152 replace this with a different implementation.
153
154 """
155 sys.stderr.write(data)
156
157
158class InteractiveConsole(InteractiveInterpreter):
159 """Closely emulate the behavior of the interactive Python interpreter.
160
161 This class builds on InteractiveInterpreter and adds prompting
162 using the familiar sys.ps1 and sys.ps2, and input buffering.
163
164 """
165
166 def __init__(self, locals=None, filename="<console>"):
167 """Constructor.
168
169 The optional locals argument will be passed to the
170 InteractiveInterpreter base class.
171
172 The optional filename argument should specify the (file)name
173 of the input stream; it will show up in tracebacks.
174
175 """
176 InteractiveInterpreter.__init__(self, locals)
177 self.filename = filename
Guido van Rossuma93b8481998-06-23 19:31:19 +0000178 self.resetbuffer()
179
180 def resetbuffer(self):
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000181 """Reset the input buffer."""
Guido van Rossuma93b8481998-06-23 19:31:19 +0000182 self.buffer = []
183
184 def interact(self, banner=None):
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000185 """Closely emulate the interactive Python console.
186
Guido van Rossum33d26892007-08-05 15:29:28 +0000187 The optional banner argument specifies the banner to print
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000188 before the first interaction; by default it prints a banner
189 similar to the one printed by the real Python interpreter,
190 followed by the current class name in parentheses (so as not
191 to confuse this with the real interpreter -- since it's so
192 close!).
193
194 """
Guido van Rossuma93b8481998-06-23 19:31:19 +0000195 try:
196 sys.ps1
197 except AttributeError:
198 sys.ps1 = ">>> "
199 try:
200 sys.ps2
201 except AttributeError:
202 sys.ps2 = "... "
Skip Montanaroacb29ae2002-03-25 22:04:23 +0000203 cprt = 'Type "help", "copyright", "credits" or "license" for more information.'
Guido van Rossuma93b8481998-06-23 19:31:19 +0000204 if banner is None:
205 self.write("Python %s on %s\n%s\n(%s)\n" %
Guido van Rossumc5f15b02001-01-14 23:04:22 +0000206 (sys.version, sys.platform, cprt,
Guido van Rossuma93b8481998-06-23 19:31:19 +0000207 self.__class__.__name__))
Guido van Rossum45e2fbc1998-03-26 21:13:24 +0000208 else:
Guido van Rossuma93b8481998-06-23 19:31:19 +0000209 self.write("%s\n" % str(banner))
210 more = 0
211 while 1:
212 try:
213 if more:
214 prompt = sys.ps2
215 else:
216 prompt = sys.ps1
217 try:
218 line = self.raw_input(prompt)
219 except EOFError:
220 self.write("\n")
221 break
222 else:
223 more = self.push(line)
224 except KeyboardInterrupt:
225 self.write("\nKeyboardInterrupt\n")
226 self.resetbuffer()
227 more = 0
228
229 def push(self, line):
230 """Push a line to the interpreter.
231
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000232 The line should not have a trailing newline; it may have
233 internal newlines. The line is appended to a buffer and the
234 interpreter's runsource() method is called with the
235 concatenated contents of the buffer as source. If this
236 indicates that the command was executed or invalid, the buffer
237 is reset; otherwise, the command is incomplete, and the buffer
238 is left as it was after the line was appended. The return
239 value is 1 if more input is required, 0 if the line was dealt
240 with in some way (this is the same as runsource()).
Guido van Rossuma93b8481998-06-23 19:31:19 +0000241
242 """
243 self.buffer.append(line)
Eric S. Raymond6b71e742001-02-09 08:56:30 +0000244 source = "\n".join(self.buffer)
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000245 more = self.runsource(source, self.filename)
246 if not more:
Guido van Rossuma93b8481998-06-23 19:31:19 +0000247 self.resetbuffer()
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000248 return more
Guido van Rossuma93b8481998-06-23 19:31:19 +0000249
250 def raw_input(self, prompt=""):
251 """Write a prompt and read a line.
252
253 The returned line does not include the trailing newline.
254 When the user enters the EOF key sequence, EOFError is raised.
255
Guido van Rossum83210b92008-01-02 02:55:27 +0000256 The base implementation uses the built-in function
257 input(); a subclass may replace this with a different
258 implementation.
Guido van Rossuma93b8481998-06-23 19:31:19 +0000259
260 """
Guido van Rossum83210b92008-01-02 02:55:27 +0000261 return input(prompt)
Neal Norwitzce96f692006-03-17 06:49:51 +0000262
Guido van Rossuma93b8481998-06-23 19:31:19 +0000263
264
Guido van Rossumd90ae191998-10-19 18:42:53 +0000265def interact(banner=None, readfunc=None, local=None):
Guido van Rossuma93b8481998-06-23 19:31:19 +0000266 """Closely emulate the interactive Python interpreter.
267
268 This is a backwards compatible interface to the InteractiveConsole
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000269 class. When readfunc is not specified, it attempts to import the
270 readline module to enable GNU readline if it is available.
Guido van Rossuma93b8481998-06-23 19:31:19 +0000271
272 Arguments (all optional, all default to None):
273
274 banner -- passed to InteractiveConsole.interact()
275 readfunc -- if not None, replaces InteractiveConsole.raw_input()
Guido van Rossumd90ae191998-10-19 18:42:53 +0000276 local -- passed to InteractiveInterpreter.__init__()
Guido van Rossuma93b8481998-06-23 19:31:19 +0000277
278 """
Guido van Rossumd90ae191998-10-19 18:42:53 +0000279 console = InteractiveConsole(local)
Guido van Rossuma93b8481998-06-23 19:31:19 +0000280 if readfunc is not None:
281 console.raw_input = readfunc
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000282 else:
283 try:
284 import readline
Skip Montanaro0679a732002-03-25 21:44:07 +0000285 except ImportError:
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000286 pass
Guido van Rossuma93b8481998-06-23 19:31:19 +0000287 console.interact(banner)
Guido van Rossum5227f0f1998-09-22 20:38:53 +0000288
289
Guido van Rossum90981e01997-10-07 14:47:24 +0000290if __name__ == '__main__':
Guido van Rossum4b499dd32003-02-13 22:07:59 +0000291 import pdb
292 pdb.run("interact()\n")