Hello all,
There is an annoying bug with IronPython 2 which is blocking me from
implementing an 'interactive interpreter in the browser'.
I'm afraid I can only show how to reproduce the bug rather than diagnose
the cause.
When executing code with the 'InteractiveInterpreter' class from the
standard library code module, the result of the last expression is sent
to stdout. This mirrors the behaviour of the normal Python interactive
interpreter.
In IronPython 1.1 this works fine - and I can trap the output by
replacing 'sys.stdout' with my own Python object.
In IronPython 2, this output just doesn't appear. :-(
If you run 'test_console.py' (with the other attached files in the same
directory) with IronPython 1.1 it will print the following line to
standard out "Received (out) : 3Received (out) :".
If you run it with IronPython 2 (I've tried it with both Silverlight and
2.0a4) it outputs nothing.
This is a darn shame because having an interactive interpreter in the
browser is way cool...
Michael Foord
http://www.manning.com/foord
import sys
class Writer(object):
def __init__(self, name):
self.name = name
def write(self, text):
sys.__stdout__.write('Received (%s) : %s' % (self.name, text))
output_writer = Writer('out')
error_writer = Writer('err')
sys.stdout = output_writer
sys.stderr = error_writer
from ipcode import InteractiveInterpreter
i = InteractiveInterpreter()
i.runsource('3')
"""Extract, format and print information about Python stack traces."""
import sys
import types
__all__ = ['extract_stack', 'extract_tb', 'format_exception',
'format_exception_only', 'format_list', 'format_stack',
'format_tb', 'print_exc', 'format_exc', 'print_exception',
'print_last', 'print_stack', 'print_tb', 'tb_lineno']
def _print(file, str='', terminator='\n'):
file.write(str+terminator)
def print_list(extracted_list, file=None):
"""Print the list of tuples as returned by extract_tb() or
extract_stack() as a formatted stack trace to the given file."""
if file is None:
file = sys.stderr
for filename, lineno, name, line in extracted_list:
_print(file,
' File "%s", line %d, in %s' % (filename,lineno,name))
if line:
_print(file, ' %s' % line.strip())
def format_list(extracted_list):
"""Format a list of traceback entry tuples for printing.
Given a list of tuples as returned by extract_tb() or
extract_stack(), return a list of strings ready for printing.
Each string in the resulting list corresponds to the item with the
same index in the argument list. Each string ends in a newline;
the strings may contain internal newlines as well, for those items
whose source text line is not None.
"""
list = []
for filename, lineno, name, line in extracted_list:
item = ' File "%s", line %d, in %s\n' % (filename,lineno,name)
if line:
item = item + ' %s\n' % line.strip()
list.append(item)
return list
def print_tb(tb, limit=None, file=None):
"""Print up to 'limit' stack trace entries from the traceback 'tb'.
If 'limit' is omitted or None, all entries are printed. If 'file'
is omitted or None, the output goes to sys.stderr; otherwise
'file' should be an open file or file-like object with a write()
method.
"""
if file is None:
file = sys.stderr
if limit is None:
if hasattr(sys, 'tracebacklimit'):
limit = sys.tracebacklimit
n = 0
while tb is not None and (limit is None or n < limit):
f = tb.tb_frame
lineno = tb.tb_lineno
co = f.f_code
filename = co.co_filename
name = co.co_name
_print(file,
' File "%s", line %d, in %s' % (filename,lineno,name))
tb = tb.tb_next
n = n+1
def format_tb(tb, limit = None):
"""A shorthand for 'format_list(extract_stack(f, limit))."""
return format_list(extract_tb(tb, limit))
def extract_tb(tb, limit = None):
"""Return list of up to limit pre-processed entries from traceback.
This is useful for alternate formatting of stack traces. If
'limit' is omitted or None, all entries are extracted. A
pre-processed stack trace entry is a quadruple (filename, line
number, function name, text) representing the information that is
usually printed for a stack trace. The text is a string with
leading and trailing whitespace stripped; if the source is not
available it is None.
"""
if limit is None:
if hasattr(sys, 'tracebacklimit'):
limit = sys.tracebacklimit
list = []
n = 0
while tb is not None and (limit is None or n < limit):
f = tb.tb_frame
lineno = tb.tb_lineno
co = f.f_code
filename = co.co_filename
name = co.co_name
line = None
list.append((filename, lineno, name, line))
tb = tb.tb_next
n = n+1
return list
def print_exception(etype, value, tb, limit=None, file=None):
"""Print exception up to 'limit' stack trace entries from 'tb' to 'file'.
This differs from print_tb() in the following ways: (1) if
traceback is not None, it prints a header "Traceback (most recent
call last):"; (2) it prints the exception type and value after the
stack trace; (3) if type is SyntaxError and value has the
appropriate format, it prints the line where the syntax error
occurred with a caret on the next line indicating the approximate
position of the error.
"""
if file is None:
file = sys.stderr
if tb:
_print(file, 'Traceback (most recent call last):')
print_tb(tb, limit, file)
lines = format_exception_only(etype, value)
for line in lines[:-1]:
_print(file, line, ' ')
_print(file, lines[-1], '')
def format_exception(etype, value, tb, limit = None):
"""Format a stack trace and the exception information.
The arguments have the same meaning as the corresponding arguments
to print_exception(). The return value is a list of strings, each
ending in a newline and some containing internal newlines. When
these lines are concatenated and printed, exactly the same text is
printed as does print_exception().
"""
if tb:
list = ['Traceback (most recent call last):\n']
list = list + format_tb(tb, limit)
else:
list = []
list = list + format_exception_only(etype, value)
return list
def format_exception_only(etype, value):
"""Format the exception part of a traceback.
The arguments are the exception type and value such as given by
sys.last_type and sys.last_value. The return value is a list of
strings, each ending in a newline. Normally, the list contains a
single string; however, for SyntaxError exceptions, it contains
several lines that (when printed) display detailed information
about where the syntax error occurred. The message indicating
which exception occurred is the always last string in the list.
"""
list = []
if type(etype) == types.ClassType:
stype = etype.__name__
else:
stype = etype
if value is None:
list.append(str(stype) + '\n')
else:
if etype is SyntaxError:
try:
msg, (filename, lineno, offset, line) = value
except:
pass
else:
if not filename: filename = "<string>"
list.append(' File "%s", line %d\n' %
(filename, lineno))
if line is not None:
i = 0
while i < len(line) and line[i].isspace():
i = i+1
list.append(' %s\n' % line.strip())
if offset is not None:
s = ' '
for c in line[i:offset-1]:
if c.isspace():
s = s + c
else:
s = s + ' '
list.append('%s^\n' % s)
value = msg
s = _some_str(value)
if s:
list.append('%s: %s\n' % (str(stype), s))
else:
list.append('%s\n' % str(stype))
return list
def _some_str(value):
try:
return str(value)
except:
return '<unprintable %s object>' % type(value).__name__
def print_exc(limit=None, file=None):
"""Shorthand for 'print_exception(sys.exc_type, sys.exc_value,
sys.exc_traceback, limit, file)'.
(In fact, it uses sys.exc_info() to retrieve the same information
in a thread-safe way.)"""
if file is None:
file = sys.stderr
try:
etype, value, tb = sys.exc_info()
print_exception(etype, value, tb, limit, file)
finally:
etype = value = tb = None
def format_exc(limit=None):
"""Like print_exc() but return a string."""
try:
etype, value, tb = sys.exc_info()
return ''.join(format_exception(etype, value, tb, limit))
finally:
etype = value = tb = None
def print_last(limit=None, file=None):
"""This is a shorthand for 'print_exception(sys.last_type,
sys.last_value, sys.last_traceback, limit, file)'."""
if file is None:
file = sys.stderr
print_exception(sys.last_type, sys.last_value, sys.last_traceback,
limit, file)
def print_stack(f=None, limit=None, file=None):
"""Print a stack trace from its invocation point.
The optional 'f' argument can be used to specify an alternate
stack frame at which to start. The optional 'limit' and 'file'
arguments have the same meaning as for print_exception().
"""
if f is None:
try:
raise ZeroDivisionError
except ZeroDivisionError:
f = sys.exc_info()[2].tb_frame.f_back
print_list(extract_stack(f, limit), file)
def format_stack(f=None, limit=None):
"""Shorthand for 'format_list(extract_stack(f, limit))'."""
if f is None:
try:
raise ZeroDivisionError
except ZeroDivisionError:
f = sys.exc_info()[2].tb_frame.f_back
return format_list(extract_stack(f, limit))
def extract_stack(f=None, limit = None):
"""Extract the raw traceback from the current stack frame.
The return value has the same format as for extract_tb(). The
optional 'f' and 'limit' arguments have the same meaning as for
print_stack(). Each item in the list is a quadruple (filename,
line number, function name, text), and the entries are in order
from oldest to newest stack frame.
"""
if f is None:
try:
raise ZeroDivisionError
except ZeroDivisionError:
f = sys.exc_info()[2].tb_frame.f_back
if limit is None:
if hasattr(sys, 'tracebacklimit'):
limit = sys.tracebacklimit
list = []
n = 0
while f is not None and (limit is None or n < limit):
lineno = f.f_lineno
co = f.f_code
filename = co.co_filename
name = co.co_name
line = None
list.append((filename, lineno, name, line))
f = f.f_back
n = n+1
list.reverse()
return list
def tb_lineno(tb):
"""Calculate correct line number of traceback given in tb.
Obsolete in 2.3.
"""
return tb.tb_lineno
"""Define names for all type symbols known in the standard interpreter.
Types that are part of optional modules (e.g. array) are not listed.
"""
import sys
# Iterators in Python aren't a matter of type but of protocol. A large
# and changing number of builtin types implement *some* flavor of
# iterator. Don't check the type! Use hasattr to check for both
# "__iter__" and "next" attributes instead.
NoneType = type(None)
TypeType = type
ObjectType = object
IntType = int
LongType = long
FloatType = float
BooleanType = bool
try:
ComplexType = complex
except NameError:
pass
StringType = str
# StringTypes is already outdated. Instead of writing "type(x) in
# types.StringTypes", you should use "isinstance(x, basestring)". But
# we keep around for compatibility with Python 2.2.
try:
UnicodeType = unicode
StringTypes = (StringType, UnicodeType)
except NameError:
StringTypes = (StringType,)
BufferType = buffer
TupleType = tuple
ListType = list
DictType = DictionaryType = dict
def _f(): pass
FunctionType = type(_f)
LambdaType = type(lambda: None) # Same as FunctionType
try:
CodeType = type(_f.func_code)
except RuntimeError:
# Execution in restricted environment
pass
def _g():
yield 1
GeneratorType = type(_g())
class _C:
def _m(self): pass
ClassType = type(_C)
UnboundMethodType = type(_C._m) # Same as MethodType
_x = _C()
InstanceType = type(_x)
MethodType = type(_x._m)
BuiltinFunctionType = type(len)
BuiltinMethodType = type([].append) # Same as BuiltinFunctionType
ModuleType = type(sys)
XRangeType = xrange
try:
raise TypeError
except TypeError:
try:
tb = sys.exc_info()[2]
TracebackType = type(tb)
FrameType = type(tb.tb_frame)
except AttributeError:
# In the restricted environment, exc_info returns (None, None,
# None) Then, tb.tb_frame gives an attribute error
pass
tb = None; del tb
SliceType = slice
EllipsisType = type(Ellipsis)
DictProxyType = type(TypeType.__dict__)
NotImplementedType = type(NotImplemented)
del sys, _f, _g, _C, _x # Not for export
"""Record of phased-in incompatible language changes.
Each line is of the form:
FeatureName = "_Feature(" OptionalRelease "," MandatoryRelease ","
CompilerFlag ")"
where, normally, OptionalRelease < MandatoryRelease, and both are 5-tuples
of the same form as sys.version_info:
(PY_MAJOR_VERSION, # the 2 in 2.1.0a3; an int
PY_MINOR_VERSION, # the 1; an int
PY_MICRO_VERSION, # the 0; an int
PY_RELEASE_LEVEL, # "alpha", "beta", "candidate" or "final"; string
PY_RELEASE_SERIAL # the 3; an int
)
OptionalRelease records the first release in which
from __future__ import FeatureName
was accepted.
In the case of MandatoryReleases that have not yet occurred,
MandatoryRelease predicts the release in which the feature will become part
of the language.
Else MandatoryRelease records when the feature became part of the language;
in releases at or after that, modules no longer need
from __future__ import FeatureName
to use the feature in question, but may continue to use such imports.
MandatoryRelease may also be None, meaning that a planned feature got
dropped.
Instances of class _Feature have two corresponding methods,
.getOptionalRelease() and .getMandatoryRelease().
CompilerFlag is the (bitfield) flag that should be passed in the fourth
argument to the builtin function compile() to enable the feature in
dynamically compiled code. This flag is stored in the .compiler_flag
attribute on _Future instances. These values must match the appropriate
#defines of CO_xxx flags in Include/compile.h.
No feature line is ever to be deleted from this file.
"""
all_feature_names = [
"nested_scopes",
"generators",
"division",
]
__all__ = ["all_feature_names"] + all_feature_names
# The CO_xxx symbols are defined here under the same names used by
# compile.h, so that an editor search will find them here. However,
# they're not exported in __all__, because they don't really belong to
# this module.
CO_NESTED = 0x0010 # nested_scopes
CO_GENERATOR_ALLOWED = 0x1000 # generators
CO_FUTURE_DIVISION = 0x2000 # division
class _Feature:
def __init__(self, optionalRelease, mandatoryRelease, compiler_flag):
self.optional = optionalRelease
self.mandatory = mandatoryRelease
self.compiler_flag = compiler_flag
def getOptionalRelease(self):
"""Return first release in which this feature was recognized.
This is a 5-tuple, of the same form as sys.version_info.
"""
return self.optional
def getMandatoryRelease(self):
"""Return release in which this feature will become mandatory.
This is a 5-tuple, of the same form as sys.version_info, or, if
the feature was dropped, is None.
"""
return self.mandatory
def __repr__(self):
return "_Feature" + repr((self.optional,
self.mandatory,
self.compiler_flag))
nested_scopes = _Feature((2, 1, 0, "beta", 1),
(2, 2, 0, "alpha", 0),
CO_NESTED)
generators = _Feature((2, 2, 0, "alpha", 1),
(2, 3, 0, "final", 0),
CO_GENERATOR_ALLOWED)
division = _Feature((2, 2, 0, "alpha", 2),
(3, 0, 0, "alpha", 0),
CO_FUTURE_DIVISION)
"""Utilities needed to emulate Python's interactive interpreter.
"""
# Inspired by similar code by Jeff Epler and Fredrik Lundh.
import sys
import traceback
from ipcodeop import CommandCompiler, compile_command
__all__ = ["InteractiveInterpreter", "InteractiveConsole", "interact",
"compile_command"]
class InteractiveInterpreter:
"""Base class for InteractiveConsole.
This class deals with parsing and interpreter state (the user's
namespace); it doesn't deal with input buffering or prompting or
input file naming (the filename is always passed in explicitly).
"""
def __init__(self, locals=None):
"""Constructor.
The optional 'locals' argument specifies the dictionary in
which code will be executed; it defaults to a newly created
dictionary with key "__name__" set to "__console__" and key
"__doc__" set to None.
"""
if locals is None:
locals = {"__name__": "__console__", "__doc__": None}
self.locals = locals
self.compile = CommandCompiler()
def runsource(self, source, filename="<input>", symbol="single"):
"""Compile and run some source in the interpreter.
Arguments are as for compile_command().
One several things can happen:
1) The input is incorrect; compile_command() raised an
exception (SyntaxError or OverflowError). A syntax traceback
will be printed by calling the showsyntaxerror() method.
2) The input is incomplete, and more input is required;
compile_command() returned None. Nothing happens.
3) The input is complete; compile_command() returned a code
object. The code is executed by calling self.runcode() (which
also handles run-time exceptions, except for SystemExit).
The return value is True in case 2, False in the other cases (unless
an exception is raised). The return value can be used to
decide whether to use sys.ps1 or sys.ps2 to prompt the next
line.
"""
try:
code = self.compile(source, filename, symbol)
except (OverflowError, SyntaxError, ValueError):
# Case 1
self.showsyntaxerror(filename)
return False
if code is None:
# Case 2
return True
# Case 3
self.runcode(code)
return False
def runcode(self, code):
"""Execute a code object.
When an exception occurs, self.showtraceback() is called to
display a traceback. All exceptions are caught except
SystemExit, which is reraised.
A note about KeyboardInterrupt: this exception may occur
elsewhere in this code, and may not always be caught. The
caller should be prepared to deal with it.
"""
try:
exec code in self.locals
except SystemExit:
raise
except:
self.showtraceback()
def showsyntaxerror(self, filename=None):
"""Display the syntax error that just occurred.
This doesn't display a stack trace because there isn't one.
If a filename is given, it is stuffed in the exception instead
of what was there before (because Python's parser always uses
"<string>" when reading from a string).
The output is written by self.write(), below.
"""
type, value, sys.last_traceback = sys.exc_info()
sys.last_type = type
sys.last_value = value
if filename and type is SyntaxError:
# Work hard to stuff the correct filename in the exception
try:
msg, (dummy_filename, lineno, offset, line) = value
except:
# Not the format we expect; leave it alone
pass
else:
# Stuff in the right filename
value = SyntaxError(msg, (filename, lineno, offset, line))
sys.last_value = value
list = traceback.format_exception_only(type, value)
map(self.write, list)
def showtraceback(self):
"""Display the exception that just occurred.
We remove the first stack item because it is our own code.
The output is written by self.write(), below.
"""
try:
type, value, tb = sys.exc_info()
sys.last_type = type
sys.last_value = value
sys.last_traceback = tb
tblist = traceback.extract_tb(tb)
del tblist[:1]
list = traceback.format_list(tblist)
if list:
list.insert(0, "Traceback (most recent call last):\n")
list[len(list):] = traceback.format_exception_only(type, value)
finally:
tblist = tb = None
map(self.write, list)
def write(self, data):
"""Write a string.
The base implementation writes to sys.stderr; a subclass may
replace this with a different implementation.
"""
sys.stderr.write(data)
class InteractiveConsole(InteractiveInterpreter):
"""Closely emulate the behavior of the interactive Python interpreter.
This class builds on InteractiveInterpreter and adds prompting
using the familiar sys.ps1 and sys.ps2, and input buffering.
"""
def __init__(self, locals=None, filename="<console>"):
"""Constructor.
The optional locals argument will be passed to the
InteractiveInterpreter base class.
The optional filename argument should specify the (file)name
of the input stream; it will show up in tracebacks.
"""
InteractiveInterpreter.__init__(self, locals)
self.filename = filename
self.resetbuffer()
def resetbuffer(self):
"""Reset the input buffer."""
self.buffer = []
def interact(self, banner=None):
"""Closely emulate the interactive Python console.
The optional banner argument specify the banner to print
before the first interaction; by default it prints a banner
similar to the one printed by the real Python interpreter,
followed by the current class name in parentheses (so as not
to confuse this with the real interpreter -- since it's so
close!).
"""
try:
sys.ps1
except AttributeError:
sys.ps1 = ">>> "
try:
sys.ps2
except AttributeError:
sys.ps2 = "... "
cprt = 'Type "help", "copyright", "credits" or "license" for more
information.'
if banner is None:
self.write("Python %s on %s\n%s\n(%s)\n" %
(sys.version, sys.platform, cprt,
self.__class__.__name__))
else:
self.write("%s\n" % str(banner))
more = 0
while 1:
try:
if more:
prompt = sys.ps2
else:
prompt = sys.ps1
try:
line = self.raw_input(prompt)
except EOFError:
self.write("\n")
break
else:
more = self.push(line)
except KeyboardInterrupt:
self.write("\nKeyboardInterrupt\n")
self.resetbuffer()
more = 0
def push(self, line):
"""Push a line to the interpreter.
The line should not have a trailing newline; it may have
internal newlines. The line is appended to a buffer and the
interpreter's runsource() method is called with the
concatenated contents of the buffer as source. If this
indicates that the command was executed or invalid, the buffer
is reset; otherwise, the command is incomplete, and the buffer
is left as it was after the line was appended. The return
value is 1 if more input is required, 0 if the line was dealt
with in some way (this is the same as runsource()).
"""
self.buffer.append(line)
source = "\n".join(self.buffer)
more = self.runsource(source, self.filename)
if not more:
self.resetbuffer()
return more
def raw_input(self, prompt=""):
"""Write a prompt and read a line.
The returned line does not include the trailing newline.
When the user enters the EOF key sequence, EOFError is raised.
The base implementation uses the built-in function
raw_input(); a subclass may replace this with a different
implementation.
"""
return raw_input(prompt)
def interact(banner=None, readfunc=None, local=None):
"""Closely emulate the interactive Python interpreter.
This is a backwards compatible interface to the InteractiveConsole
class. When readfunc is not specified, it attempts to import the
readline module to enable GNU readline if it is available.
Arguments (all optional, all default to None):
banner -- passed to InteractiveConsole.interact()
readfunc -- if not None, replaces InteractiveConsole.raw_input()
local -- passed to InteractiveInterpreter.__init__()
"""
console = InteractiveConsole(local)
if readfunc is not None:
console.raw_input = readfunc
else:
try:
import readline
except ImportError:
pass
console.interact(banner)
if __name__ == '__main__':
import pdb
pdb.run("interact()\n")
r"""Utilities to compile possibly incomplete Python source code.
This module provides two interfaces, broadly similar to the builtin
function compile(), which take program text, a filename and a 'mode'
and:
- Return code object if the command is complete and valid
- Return None if the command is incomplete
- Raise SyntaxError, ValueError or OverflowError if the command is a
syntax error (OverflowError and ValueError can be produced by
malformed literals).
Approach:
First, check if the source consists entirely of blank lines and
comments; if so, replace it with 'pass', because the built-in
parser doesn't always do the right thing for these.
Compile three times: as is, with \n, and with \n\n appended. If it
compiles as is, it's complete. If it compiles with one \n appended,
we expect more. If it doesn't compile either way, we compare the
error we get when compiling with \n or \n\n appended. If the errors
are the same, the code is broken. But if the errors are different, we
expect more. Not intuitive; not even guaranteed to hold in future
releases; but this matches the compiler's behavior from Python 1.4
through 2.2, at least.
Caveat:
It is possible (but not likely) that the parser stops parsing with a
successful outcome before reaching the end of the source; in this
case, trailing symbols may be ignored instead of causing an error.
For example, a backslash followed by two newlines may be followed by
arbitrary garbage. This will be fixed once the API for the parser is
better.
The two interfaces are:
compile_command(source, filename, symbol):
Compiles a single command in the manner described above.
CommandCompiler():
Instances of this class have __call__ methods identical in
signature to compile_command; the difference is that if the
instance compiles program text containing a __future__ statement,
the instance 'remembers' and compiles all subsequent program texts
with the statement in force.
The module also provides another class:
Compile():
Instances of this class act like the built-in function compile,
but with 'memory' in the sense described above.
"""
import __future__
_features = [getattr(__future__, fname)
for fname in __future__.all_feature_names]
__all__ = ["compile_command", "Compile", "CommandCompiler"]
PyCF_DONT_IMPLY_DEDENT = 0x200 # Matches pythonrun.h
def _maybe_compile(compiler, source, filename, symbol):
# Check for source consisting of only blank lines and comments
for line in source.split("\n"):
line = line.strip()
if line and line[0] != '#':
break # Leave it alone
else:
if symbol != "eval":
source = "pass" # Replace it with a 'pass' statement
err = err1 = err2 = None
code = code1 = code2 = None
try:
code = compiler(source, filename, symbol)
except SyntaxError, err:
pass
try:
code1 = compiler(source + "\n", filename, symbol)
except SyntaxError, err1:
pass
try:
code2 = compiler(source + "\n\n", filename, symbol)
except SyntaxError, err2:
pass
if code:
return code
try:
e1 = err1.__dict__
except AttributeError:
e1 = err1
try:
e2 = err2.__dict__
except AttributeError:
e2 = err2
if not code1 and e1 == e2:
raise SyntaxError, err1
def _compile(source, filename, symbol):
return compile(source, filename, symbol, PyCF_DONT_IMPLY_DEDENT)
def compile_command(source, filename="<input>", symbol="single"):
r"""Compile a command and determine whether it is incomplete.
Arguments:
source -- the source string; may contain \n characters
filename -- optional filename from which source was read; default
"<input>"
symbol -- optional grammar start symbol; "single" (default) or "eval"
Return value / exceptions raised:
- Return a code object if the command is complete and valid
- Return None if the command is incomplete
- Raise SyntaxError, ValueError or OverflowError if the command is a
syntax error (OverflowError and ValueError can be produced by
malformed literals).
"""
return _maybe_compile(_compile, source, filename, symbol)
class Compile:
"""Instances of this class behave much like the built-in compile
function, but if one is used to compile text containing a future
statement, it "remembers" and compiles all subsequent program texts
with the statement in force."""
def __init__(self):
self.flags = 0
def __call__(self, source, filename, symbol):
codeob = compile(source, filename, symbol, self.flags, 1)
for feature in _features:
if codeob.co_flags & feature.compiler_flag:
self.flags |= feature.compiler_flag
return codeob
class CommandCompiler:
"""Instances of this class have __call__ methods identical in
signature to compile_command; the difference is that if the
instance compiles program text containing a __future__ statement,
the instance 'remembers' and compiles all subsequent program texts
with the statement in force."""
def __init__(self,):
self.compiler = Compile()
def __call__(self, source, filename="<input>", symbol="single"):
r"""Compile a command and determine whether it is incomplete.
Arguments:
source -- the source string; may contain \n characters
filename -- optional filename from which source was read;
default "<input>"
symbol -- optional grammar start symbol; "single" (default) or
"eval"
Return value / exceptions raised:
- Return a code object if the command is complete and valid
- Return None if the command is incomplete
- Raise SyntaxError, ValueError or OverflowError if the command is a
syntax error (OverflowError and ValueError can be produced by
malformed literals).
"""
return _maybe_compile(self.compiler, source, filename, symbol)
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