d14a1e2856
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@24541 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
257 lines
8.3 KiB
Python
257 lines
8.3 KiB
Python
#----------------------------------------------------------------------------
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# Name: dbg.py
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# RCS-ID: $Id$
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# Author: Will Sadkin
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# Email: wsadkin@nameconnector.com
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# Created: 07/11/2002
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# Copyright: (c) 2002 by Will Sadkin, 2002
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# License: wxWindows license
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#----------------------------------------------------------------------------
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"""
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This module provides a useful debugging framework that supports
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showing nesting of function calls and allows a program to contain
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lots of debugging print statements that can easily be turned on
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or off to debug the code. It also supports the ability to
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have each function indent the debugging statements contained
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within it, including those of any other function called within
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its scope, thus allowing you to see in what order functions are
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being called, and from where.
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This capability is particularly useful in wxPython applications,
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where exactly events occur that cause functions to be called is
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not entirely clear, and because wxPython programs can't be run
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from inside other debugging environments that have their own
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message loops.
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This module defines a Logger class, responsible for managing
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debugging output. Each Logger instance can be given a name
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at construction; if this is done, '<name>:' will precede each
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logging output made by that Logger instance.
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The log() function this class provides takes a set of positional
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arguments that are printed in order if debugging is enabled
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(just like print does), followed by a set of keyword arguments
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that control the behavior of the log() function itself on subsequent
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calls. The current keyword arguments are:
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indent
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When set to a value of 1, this increments the current
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indentation level, causing all subsequent dbg() outputs to be
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indented by 3 more spaces. When set to a value of 0,
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this process is reversed, causing the indent to decrease by
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3 spaces. The default indentation level is 0.
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enable
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When set to a value of 1, this turns on dbg() output for
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for program importing this module, until told to do otherwise.
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When set to a value of 0, dbg output is turned off. (dbg
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output is off by default.)
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suspend
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When set to a value of 1, this increments the current
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"suspension" level. This makes it possible for a function
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to temporarily suspend its and any of its dependents'
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potential outputs that use the same Logger instance.
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When set to a value of 0, the suspension level is
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decremented. When the value goes back to 0, potential
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logging is resumed (actual output depends on the
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"enable" status of the Logger instance in question.)
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wxlog
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When set to a value of 1, the output will be sent to the
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active wxLog target.
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stream
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When set to a non-None value, the current output stream
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(default of sys.stdout) is pushed onto a stack of streams,
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and is replaced in the dbg system with the specified stream.
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When called with a value of None, the previous stream will
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be restored (if stacked.) If set to None without previously
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changing it will result in no action being taken.
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You can also call the log function implicitly on the Logger
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instance, ie. you can type:
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from wxPython.tools.dbg import Logger
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dbg = Logger()
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dbg('something to print')
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Using this fairly simple mechanism, it is possible to get fairly
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useful debugging output in a program. Consider the following
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code example:
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>>> d = {1:'a', 2:'dictionary', 3:'of', 4:'words'}
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>>> dbg = dbg.Logger('module')
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>>> dbg(enable=1)
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module: dbg enabled
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>>> def foo(d):
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... dbg('foo', indent=1)
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... bar(d)
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... dbg('end of foo', indent=0)
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...
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>>> def bar(d):
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... dbg('bar', indent=1)
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... dbg('contents of d:', indent=1)
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... l = d.items()
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... l.sort()
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... for key, value in l:
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... dbg('%d =' % key, value)
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... dbg(indent=0)
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... dbg('end of bar', indent=0)
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...
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>>> foo(d)
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module: foo
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module: bar
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module: contents of d:
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module: 1 = a
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module: 2 = dictionary
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module: 3 = of
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module: 4 = words
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module: end of bar
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module: end of foo
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>>>
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"""
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class Logger:
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def __init__(self, name=None):
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import sys
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self.name = name
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self._indent = 0 # current number of indentations
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self._dbg = 0 # enable/disable flag
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self._suspend = 0 # allows code to "suspend/resume" potential dbg output
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self._wxLog = 0 # use wxLogMessage for debug output
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self._outstream = sys.stdout # default output stream
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self._outstream_stack = [] # for restoration of streams as necessary
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def IsEnabled():
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return self._dbg
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def IsSuspended():
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return _suspend
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def log(self, *args, **kwargs):
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"""
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This function provides a useful framework for generating
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optional debugging output that can be displayed at an
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arbitrary level of indentation.
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"""
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if not self._dbg and not 'enable' in kwargs.keys():
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return
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if self._dbg and len(args) and not self._suspend:
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# (emulate print functionality)
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strs = [str(arg) for arg in args]
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output = ' '.join(strs)
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if self.name: output = self.name+': ' + output
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output = ' ' * 3 * self._indent + output
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if self._wxLog:
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from wxPython.wx import wxLogMessage # (if not already imported)
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wxLogMessage(output)
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else:
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self._outstream.write(output + '\n')
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self._outstream.flush()
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# else do nothing
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# post process args:
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for kwarg, value in kwargs.items():
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if kwarg == 'indent':
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self.SetIndent(value)
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elif kwarg == 'enable':
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self.SetEnabled(value)
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elif kwarg == 'suspend':
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self.SetSuspend(value)
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elif kwarg == 'wxlog':
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self.SetWxLog(value)
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elif kwarg == 'stream':
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self.SetStream(value)
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# aliases for the log function
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dbg = log # backwards compatible
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msg = log #
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__call__ = log # this one lets you 'call' the instance directly
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def SetEnabled(self, value):
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if value:
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old_dbg = self._dbg
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self._dbg = 1
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if not old_dbg:
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self.dbg('dbg enabled')
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else:
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if self._dbg:
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self.dbg('dbg disabled')
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self._dbg = 0
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def SetSuspend(self, value):
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if value:
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self._suspend += 1
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elif self._suspend > 0:
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self._suspend -= 1
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def SetIndent(self, value):
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if value:
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self._indent += 1
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elif self._indent > 0:
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self._indent -= 1
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def SetWxLog(self, value):
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self._wxLog = value
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def SetStream(self, value):
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if value:
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self._outstream_stack.append( self._outstream )
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self._outstream = value
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elif value is None and len(self._outstream_stack) > 0:
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self._outstream = self._outstream_stack.pop(-1)
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#------------------------------------------------------------
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if __name__ == "__main__":
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from wxPython.wx import *
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wxLog_SetActiveTarget( wxLogStderr() )
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logger = Logger('module')
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dbg = logger.dbg
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dbg(enable=1)
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logger('test __call__ interface')
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dbg('testing wxLog output to stderr:', wxlog=1, indent=1)
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dbg('1,2,3...')
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dbg('testing wxLogNull:')
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devnull = wxLogNull()
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dbg('4,5,6...') # shouldn't print, according to doc...
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del devnull
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dbg('(resuming to wxLogStdErr)', '7,8,9...', indent=0)
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dbg('disabling wxLog output, switching to stderr:')
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dbg(wxlog=0, stream=sys.stderr)
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dbg(logger._outstream, 'switching back to stdout:')
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dbg(stream=None)
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dbg(logger._outstream )
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def foo(str):
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dbg('foo:', indent=1)
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dbg(str, indent=0)
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foo('testing dbg inside function')
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class bar(Logger):
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def __init__(self, name):
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Logger.__init__(self, name)
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def enable(self, value):
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self.dbg(enable=value)
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def foo(self, str):
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self.dbg('foo:', indent=1)
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self.dbg(str, indent=0)
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f = bar('class mixin')
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f.foo("shouldn't print")
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f.enable(1)
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f.foo("should print")
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dbg('test completed.', enable=0)
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dbg('(double-checking ;-)')
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