Viewing file:  evalcontext.py (2.08 KB) -rw-r--r--
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# (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org)
# Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
from cStringIO import StringIO
import traceback
import threading
import pdb
import sys
exec_lock = threading.Lock()
class EvalContext(object):
"""
Class that represents a interactive interface. It has its own
namespace. Use eval_context.exec_expr(expr) to run commands; the
output of those commands is returned, as are print statements.
This is essentially what doctest does, and is taken directly from
doctest.
"""
def __init__(self, namespace, globs):
self.namespace = namespace
self.globs = globs
def exec_expr(self, s):
out = StringIO()
exec_lock.acquire()
save_stdout = sys.stdout
try:
debugger = _OutputRedirectingPdb(save_stdout)
debugger.reset()
pdb.set_trace = debugger.set_trace
sys.stdout = out
try:
code = compile(s, '<web>', "single", 0, 1)
exec code in self.namespace, self.globs
debugger.set_continue()
except KeyboardInterrupt:
raise
except:
traceback.print_exc(file=out)
debugger.set_continue()
finally:
sys.stdout = save_stdout
exec_lock.release()
return out.getvalue()
# From doctest
class _OutputRedirectingPdb(pdb.Pdb):
"""
A specialized version of the python debugger that redirects stdout
to a given stream when interacting with the user. Stdout is *not*
redirected when traced code is executed.
"""
def __init__(self, out):
self.__out = out
pdb.Pdb.__init__(self)
def trace_dispatch(self, *args):
# Redirect stdout to the given stream.
save_stdout = sys.stdout
sys.stdout = self.__out
# Call Pdb's trace dispatch method.
try:
return pdb.Pdb.trace_dispatch(self, *args)
finally:
sys.stdout = save_stdout
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