# -*- coding: utf-8 -*- """ ultraTB.py -- Spice up your tracebacks! * ColorTB I've always found it a bit hard to visually parse tracebacks in Python. The ColorTB class is a solution to that problem. It colors the different parts of a traceback in a manner similar to what you would expect from a syntax-highlighting text editor. Installation instructions for ColorTB: import sys,ultraTB sys.excepthook = ultraTB.ColorTB() * VerboseTB I've also included a port of Ka-Ping Yee's "cgitb.py" that produces all kinds of useful info when a traceback occurs. Ping originally had it spit out HTML and intended it for CGI programmers, but why should they have all the fun? I altered it to spit out colored text to the terminal. It's a bit overwhelming, but kind of neat, and maybe useful for long-running programs that you believe are bug-free. If a crash *does* occur in that type of program you want details. Give it a shot--you'll love it or you'll hate it. Note: The Verbose mode prints the variables currently visible where the exception happened (shortening their strings if too long). This can potentially be very slow, if you happen to have a huge data structure whose string representation is complex to compute. Your computer may appear to freeze for a while with cpu usage at 100%. If this occurs, you can cancel the traceback with Ctrl-C (maybe hitting it more than once). If you encounter this kind of situation often, you may want to use the Verbose_novars mode instead of the regular Verbose, which avoids formatting variables (but otherwise includes the information and context given by Verbose). Installation instructions for ColorTB: import sys,ultraTB sys.excepthook = ultraTB.VerboseTB() Note: Much of the code in this module was lifted verbatim from the standard library module 'traceback.py' and Ka-Ping Yee's 'cgitb.py'. * Color schemes The colors are defined in the class TBTools through the use of the ColorSchemeTable class. Currently the following exist: - NoColor: allows all of this module to be used in any terminal (the color escapes are just dummy blank strings). - Linux: is meant to look good in a terminal like the Linux console (black or very dark background). - LightBG: similar to Linux but swaps dark/light colors to be more readable in light background terminals. You can implement other color schemes easily, the syntax is fairly self-explanatory. Please send back new schemes you develop to the author for possible inclusion in future releases. $Id: ultraTB.py 1005 2006-01-12 08:39:26Z fperez $""" #***************************************************************************** # Copyright (C) 2001 Nathaniel Gray # Copyright (C) 2001-2004 Fernando Perez # # Distributed under the terms of the BSD License. The full license is in # the file COPYING, distributed as part of this software. #***************************************************************************** from IPython import Release __author__ = '%s <%s>\n%s <%s>' % (Release.authors['Nathan']+ Release.authors['Fernando']) __license__ = Release.license # Required modules import inspect import keyword import linecache import os import pydoc import string import sys import time import tokenize import traceback import types # IPython's own modules # Modified pdb which doesn't damage IPython's readline handling from IPython import Debugger from IPython.ipstruct import Struct from IPython.excolors import ExceptionColors from IPython.genutils import Term,uniq_stable,error,info # Globals # amount of space to put line numbers before verbose tracebacks INDENT_SIZE = 8 #--------------------------------------------------------------------------- # Code begins # Utility functions def inspect_error(): """Print a message about internal inspect errors. These are unfortunately quite common.""" error('Internal Python error in the inspect module.\n' 'Below is the traceback from this internal error.\n') def _fixed_getinnerframes(etb, context=1,tb_offset=0): import linecache LNUM_POS, LINES_POS, INDEX_POS = 2, 4, 5 records = inspect.getinnerframes(etb, context) # If the error is at the console, don't build any context, since it would # otherwise produce 5 blank lines printed out (there is no file at the # console) rec_check = records[tb_offset:] try: rname = rec_check[0][1] if rname == '' or rname.endswith(''): return rec_check except IndexError: pass aux = traceback.extract_tb(etb) assert len(records) == len(aux) for i, (file, lnum, _, _) in zip(range(len(records)), aux): maybeStart = lnum-1 - context//2 start = max(maybeStart, 0) end = start + context lines = linecache.getlines(file)[start:end] # pad with empty lines if necessary if maybeStart < 0: lines = (['\n'] * -maybeStart) + lines if len(lines) < context: lines += ['\n'] * (context - len(lines)) buf = list(records[i]) buf[LNUM_POS] = lnum buf[INDEX_POS] = lnum - 1 - start buf[LINES_POS] = lines records[i] = tuple(buf) return records[tb_offset:] # Helper function -- largely belongs to VerboseTB, but we need the same # functionality to produce a pseudo verbose TB for SyntaxErrors, so that they # can be recognized properly by ipython.el's py-traceback-line-re # (SyntaxErrors have to be treated specially because they have no traceback) def _formatTracebackLines(lnum, index, lines, Colors, lvals=None): numbers_width = INDENT_SIZE - 1 res = [] i = lnum - index for line in lines: if i == lnum: # This is the line with the error pad = numbers_width - len(str(i)) if pad >= 3: marker = '-'*(pad-3) + '-> ' elif pad == 2: marker = '> ' elif pad == 1: marker = '>' else: marker = '' num = marker + str(i) line = '%s%s%s %s%s' %(Colors.linenoEm, num, Colors.line, line, Colors.Normal) else: num = '%*s' % (numbers_width,i) line = '%s%s%s %s' %(Colors.lineno, num, Colors.Normal, line) res.append(line) if lvals and i == lnum: res.append(lvals + '\n') i = i + 1 return res #--------------------------------------------------------------------------- # Module classes class TBTools: """Basic tools used by all traceback printer classes.""" def __init__(self,color_scheme = 'NoColor',call_pdb=False): # Whether to call the interactive pdb debugger after printing # tracebacks or not self.call_pdb = call_pdb # Create color table self.color_scheme_table = ExceptionColors self.set_colors(color_scheme) self.old_scheme = color_scheme # save initial value for toggles if call_pdb: self.pdb = Debugger.Pdb(self.color_scheme_table.active_scheme_name) else: self.pdb = None def set_colors(self,*args,**kw): """Shorthand access to the color table scheme selector method.""" self.color_scheme_table.set_active_scheme(*args,**kw) # for convenience, set Colors to the active scheme self.Colors = self.color_scheme_table.active_colors def color_toggle(self): """Toggle between the currently active color scheme and NoColor.""" if self.color_scheme_table.active_scheme_name == 'NoColor': self.color_scheme_table.set_active_scheme(self.old_scheme) self.Colors = self.color_scheme_table.active_colors else: self.old_scheme = self.color_scheme_table.active_scheme_name self.color_scheme_table.set_active_scheme('NoColor') self.Colors = self.color_scheme_table.active_colors #--------------------------------------------------------------------------- class ListTB(TBTools): """Print traceback information from a traceback list, with optional color. Calling: requires 3 arguments: (etype, evalue, elist) as would be obtained by: etype, evalue, tb = sys.exc_info() if tb: elist = traceback.extract_tb(tb) else: elist = None It can thus be used by programs which need to process the traceback before printing (such as console replacements based on the code module from the standard library). Because they are meant to be called without a full traceback (only a list), instances of this class can't call the interactive pdb debugger.""" def __init__(self,color_scheme = 'NoColor'): TBTools.__init__(self,color_scheme = color_scheme,call_pdb=0) def __call__(self, etype, value, elist): print >> Term.cerr, self.text(etype,value,elist) def text(self,etype, value, elist,context=5): """Return a color formatted string with the traceback info.""" Colors = self.Colors out_string = ['%s%s%s\n' % (Colors.topline,'-'*60,Colors.Normal)] if elist: out_string.append('Traceback %s(most recent call last)%s:' % \ (Colors.normalEm, Colors.Normal) + '\n') out_string.extend(self._format_list(elist)) lines = self._format_exception_only(etype, value) for line in lines[:-1]: out_string.append(" "+line) out_string.append(lines[-1]) return ''.join(out_string) def _format_list(self, 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. Lifted almost verbatim from traceback.py """ Colors = self.Colors list = [] for filename, lineno, name, line in extracted_list[:-1]: item = ' File %s"%s"%s, line %s%d%s, in %s%s%s\n' % \ (Colors.filename, filename, Colors.Normal, Colors.lineno, lineno, Colors.Normal, Colors.name, name, Colors.Normal) if line: item = item + ' %s\n' % line.strip() list.append(item) # Emphasize the last entry filename, lineno, name, line = extracted_list[-1] item = '%s File %s"%s"%s, line %s%d%s, in %s%s%s%s\n' % \ (Colors.normalEm, Colors.filenameEm, filename, Colors.normalEm, Colors.linenoEm, lineno, Colors.normalEm, Colors.nameEm, name, Colors.normalEm, Colors.Normal) if line: item = item + '%s %s%s\n' % (Colors.line, line.strip(), Colors.Normal) list.append(item) return list def _format_exception_only(self, etype, value): """Format the exception part of a traceback. The arguments are the exception type and value such as given by sys.exc_info()[:2]. 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. Also lifted nearly verbatim from traceback.py """ Colors = self.Colors list = [] if type(etype) == types.ClassType: stype = Colors.excName + etype.__name__ + Colors.Normal else: stype = etype # String exceptions don't get special coloring if value is None: list.append( str(stype) + '\n') else: if etype is SyntaxError: try: msg, (filename, lineno, offset, line) = value except: pass else: #print 'filename is',filename # dbg if not filename: filename = "" list.append('%s File %s"%s"%s, line %s%d%s\n' % \ (Colors.normalEm, Colors.filenameEm, filename, Colors.normalEm, Colors.linenoEm, lineno, Colors.Normal )) if line is not None: i = 0 while i < len(line) and line[i].isspace(): i = i+1 list.append('%s %s%s\n' % (Colors.line, line.strip(), Colors.Normal)) 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%s^%s\n' % (Colors.caret, s, Colors.Normal) ) value = msg s = self._some_str(value) if s: list.append('%s%s:%s %s\n' % (str(stype), Colors.excName, Colors.Normal, s)) else: list.append('%s\n' % str(stype)) return list def _some_str(self, value): # Lifted from traceback.py try: return str(value) except: return '' % type(value).__name__ #---------------------------------------------------------------------------- class VerboseTB(TBTools): """A port of Ka-Ping Yee's cgitb.py module that outputs color text instead of HTML. Requires inspect and pydoc. Crazy, man. Modified version which optionally strips the topmost entries from the traceback, to be used with alternate interpreters (because their own code would appear in the traceback).""" def __init__(self,color_scheme = 'Linux',tb_offset=0,long_header=0, call_pdb = 0, include_vars=1): """Specify traceback offset, headers and color scheme. Define how many frames to drop from the tracebacks. Calling it with tb_offset=1 allows use of this handler in interpreters which will have their own code at the top of the traceback (VerboseTB will first remove that frame before printing the traceback info).""" TBTools.__init__(self,color_scheme=color_scheme,call_pdb=call_pdb) self.tb_offset = tb_offset self.long_header = long_header self.include_vars = include_vars def text(self, etype, evalue, etb, context=5): """Return a nice text document describing the traceback.""" # some locals Colors = self.Colors # just a shorthand + quicker name lookup ColorsNormal = Colors.Normal # used a lot indent = ' '*INDENT_SIZE text_repr = pydoc.text.repr exc = '%s%s%s' % (Colors.excName, str(etype), ColorsNormal) em_normal = '%s\n%s%s' % (Colors.valEm, indent,ColorsNormal) undefined = '%sundefined%s' % (Colors.em, ColorsNormal) # some internal-use functions def eqrepr(value, repr=text_repr): return '=%s' % repr(value) def nullrepr(value, repr=text_repr): return '' # meat of the code begins if type(etype) is types.ClassType: etype = etype.__name__ if self.long_header: # Header with the exception type, python version, and date pyver = 'Python ' + string.split(sys.version)[0] + ': ' + sys.executable date = time.ctime(time.time()) head = '%s%s%s\n%s%s%s\n%s' % (Colors.topline, '-'*75, ColorsNormal, exc, ' '*(75-len(str(etype))-len(pyver)), pyver, string.rjust(date, 75) ) head += "\nA problem occured executing Python code. Here is the sequence of function"\ "\ncalls leading up to the error, with the most recent (innermost) call last." else: # Simplified header head = '%s%s%s\n%s%s' % (Colors.topline, '-'*75, ColorsNormal,exc, string.rjust('Traceback (most recent call last)', 75 - len(str(etype)) ) ) frames = [] # Flush cache before calling inspect. This helps alleviate some of the # problems with python 2.3's inspect.py. linecache.checkcache() # Drop topmost frames if requested try: # Try the default getinnerframes and Alex's: Alex's fixes some # problems, but it generates empty tracebacks for console errors # (5 blanks lines) where none should be returned. #records = inspect.getinnerframes(etb, context)[self.tb_offset:] #print 'python records:', records # dbg records = _fixed_getinnerframes(etb, context,self.tb_offset) #print 'alex records:', records # dbg except: # FIXME: I've been getting many crash reports from python 2.3 # users, traceable to inspect.py. If I can find a small test-case # to reproduce this, I should either write a better workaround or # file a bug report against inspect (if that's the real problem). # So far, I haven't been able to find an isolated example to # reproduce the problem. inspect_error() traceback.print_exc(file=Term.cerr) info('\nUnfortunately, your original traceback can not be constructed.\n') return '' # build some color string templates outside these nested loops tpl_link = '%s%%s%s' % (Colors.filenameEm,ColorsNormal) tpl_call = 'in %s%%s%s%%s%s' % (Colors.vName, Colors.valEm, ColorsNormal) tpl_call_fail = 'in %s%%s%s(***failed resolving arguments***)%s' % \ (Colors.vName, Colors.valEm, ColorsNormal) tpl_local_var = '%s%%s%s' % (Colors.vName, ColorsNormal) tpl_global_var = '%sglobal%s %s%%s%s' % (Colors.em, ColorsNormal, Colors.vName, ColorsNormal) tpl_name_val = '%%s %s= %%s%s' % (Colors.valEm, ColorsNormal) tpl_line = '%s%%s%s %%s' % (Colors.lineno, ColorsNormal) tpl_line_em = '%s%%s%s %%s%s' % (Colors.linenoEm,Colors.line, ColorsNormal) # now, loop over all records printing context and info abspath = os.path.abspath for frame, file, lnum, func, lines, index in records: #print '*** record:',file,lnum,func,lines,index # dbg try: file = file and abspath(file) or '?' except OSError: # if file is '' or something not in the filesystem, # the abspath call will throw an OSError. Just ignore it and # keep the original file string. pass link = tpl_link % file try: args, varargs, varkw, locals = inspect.getargvalues(frame) except: # This can happen due to a bug in python2.3. We should be # able to remove this try/except when 2.4 becomes a # requirement. Bug details at http://python.org/sf/1005466 inspect_error() traceback.print_exc(file=Term.cerr) info("\nIPython's exception reporting continues...\n") if func == '?': call = '' else: # Decide whether to include variable details or not var_repr = self.include_vars and eqrepr or nullrepr try: call = tpl_call % (func,inspect.formatargvalues(args, varargs, varkw, locals,formatvalue=var_repr)) except KeyError: # Very odd crash from inspect.formatargvalues(). The # scenario under which it appeared was a call to # view(array,scale) in NumTut.view.view(), where scale had # been defined as a scalar (it should be a tuple). Somehow # inspect messes up resolving the argument list of view() # and barfs out. At some point I should dig into this one # and file a bug report about it. inspect_error() traceback.print_exc(file=Term.cerr) info("\nIPython's exception reporting continues...\n") call = tpl_call_fail % func # Initialize a list of names on the current line, which the # tokenizer below will populate. names = [] def tokeneater(token_type, token, start, end, line): """Stateful tokeneater which builds dotted names. The list of names it appends to (from the enclosing scope) can contain repeated composite names. This is unavoidable, since there is no way to disambguate partial dotted structures until the full list is known. The caller is responsible for pruning the final list of duplicates before using it.""" # build composite names if token == '.': try: names[-1] += '.' # store state so the next token is added for x.y.z names tokeneater.name_cont = True return except IndexError: pass if token_type == tokenize.NAME and token not in keyword.kwlist: if tokeneater.name_cont: # Dotted names names[-1] += token tokeneater.name_cont = False else: # Regular new names. We append everything, the caller # will be responsible for pruning the list later. It's # very tricky to try to prune as we go, b/c composite # names can fool us. The pruning at the end is easy # to do (or the caller can print a list with repeated # names if so desired. names.append(token) elif token_type == tokenize.NEWLINE: raise IndexError # we need to store a bit of state in the tokenizer to build # dotted names tokeneater.name_cont = False def linereader(file=file, lnum=[lnum], getline=linecache.getline): line = getline(file, lnum[0]) lnum[0] += 1 return line # Build the list of names on this line of code where the exception # occurred. try: # This builds the names list in-place by capturing it from the # enclosing scope. tokenize.tokenize(linereader, tokeneater) except IndexError: # signals exit of tokenizer pass except tokenize.TokenError,msg: _m = ("An unexpected error occurred while tokenizing input\n" "The following traceback may be corrupted or invalid\n" "The error message is: %s\n" % msg) error(_m) # prune names list of duplicates, but keep the right order unique_names = uniq_stable(names) # Start loop over vars lvals = [] if self.include_vars: for name_full in unique_names: name_base = name_full.split('.',1)[0] if name_base in frame.f_code.co_varnames: if locals.has_key(name_base): try: value = repr(eval(name_full,locals)) except: value = undefined else: value = undefined name = tpl_local_var % name_full else: if frame.f_globals.has_key(name_base): try: value = repr(eval(name_full,frame.f_globals)) except: value = undefined else: value = undefined name = tpl_global_var % name_full lvals.append(tpl_name_val % (name,value)) if lvals: lvals = '%s%s' % (indent,em_normal.join(lvals)) else: lvals = '' level = '%s %s\n' % (link,call) if index is None: frames.append(level) else: frames.append('%s%s' % (level,''.join( _formatTracebackLines(lnum,index,lines,self.Colors,lvals)))) # Get (safely) a string form of the exception info try: etype_str,evalue_str = map(str,(etype,evalue)) except: # User exception is improperly defined. etype,evalue = str,sys.exc_info()[:2] etype_str,evalue_str = map(str,(etype,evalue)) # ... and format it exception = ['%s%s%s: %s' % (Colors.excName, etype_str, ColorsNormal, evalue_str)] if type(evalue) is types.InstanceType: try: names = [w for w in dir(evalue) if isinstance(w, basestring)] except: # Every now and then, an object with funny inernals blows up # when dir() is called on it. We do the best we can to report # the problem and continue _m = '%sException reporting error (object with broken dir())%s:' exception.append(_m % (Colors.excName,ColorsNormal)) etype_str,evalue_str = map(str,sys.exc_info()[:2]) exception.append('%s%s%s: %s' % (Colors.excName,etype_str, ColorsNormal, evalue_str)) names = [] for name in names: value = text_repr(getattr(evalue, name)) exception.append('\n%s%s = %s' % (indent, name, value)) # return all our info assembled as a single string return '%s\n\n%s\n%s' % (head,'\n'.join(frames),''.join(exception[0]) ) def debugger(self): """Call up the pdb debugger if desired, always clean up the tb reference. If the call_pdb flag is set, the pdb interactive debugger is invoked. In all cases, the self.tb reference to the current traceback is deleted to prevent lingering references which hamper memory management. Note that each call to pdb() does an 'import readline', so if your app requires a special setup for the readline completers, you'll have to fix that by hand after invoking the exception handler.""" if self.call_pdb: if self.pdb is None: self.pdb = Debugger.Pdb( self.color_scheme_table.active_scheme_name) # the system displayhook may have changed, restore the original # for pdb dhook = sys.displayhook sys.displayhook = sys.__displayhook__ self.pdb.reset() # Find the right frame so we don't pop up inside ipython itself etb = self.tb while self.tb.tb_next is not None: self.tb = self.tb.tb_next try: if etb and etb.tb_next: etb = etb.tb_next self.pdb.botframe = etb.tb_frame self.pdb.interaction(self.tb.tb_frame, self.tb) except: print '*** ERROR ***' print 'This version of pdb has a bug and crashed.' print 'Returning to IPython...' sys.displayhook = dhook del self.tb def handler(self, info=None): (etype, evalue, etb) = info or sys.exc_info() self.tb = etb print >> Term.cerr, self.text(etype, evalue, etb) # Changed so an instance can just be called as VerboseTB_inst() and print # out the right info on its own. def __call__(self, etype=None, evalue=None, etb=None): """This hook can replace sys.excepthook (for Python 2.1 or higher).""" if etb is None: self.handler() else: self.handler((etype, evalue, etb)) self.debugger() #---------------------------------------------------------------------------- class FormattedTB(VerboseTB,ListTB): """Subclass ListTB but allow calling with a traceback. It can thus be used as a sys.excepthook for Python > 2.1. Also adds 'Context' and 'Verbose' modes, not available in ListTB. Allows a tb_offset to be specified. This is useful for situations where one needs to remove a number of topmost frames from the traceback (such as occurs with python programs that themselves execute other python code, like Python shells). """ def __init__(self, mode = 'Plain', color_scheme='Linux', tb_offset = 0,long_header=0,call_pdb=0,include_vars=0): # NEVER change the order of this list. Put new modes at the end: self.valid_modes = ['Plain','Context','Verbose'] self.verbose_modes = self.valid_modes[1:3] VerboseTB.__init__(self,color_scheme,tb_offset,long_header, call_pdb=call_pdb,include_vars=include_vars) self.set_mode(mode) def _extract_tb(self,tb): if tb: return traceback.extract_tb(tb) else: return None def text(self, etype, value, tb,context=5,mode=None): """Return formatted traceback. If the optional mode parameter is given, it overrides the current mode.""" if mode is None: mode = self.mode if mode in self.verbose_modes: # verbose modes need a full traceback return VerboseTB.text(self,etype, value, tb,context=5) else: # We must check the source cache because otherwise we can print # out-of-date source code. linecache.checkcache() # Now we can extract and format the exception elist = self._extract_tb(tb) if len(elist) > self.tb_offset: del elist[:self.tb_offset] return ListTB.text(self,etype,value,elist) def set_mode(self,mode=None): """Switch to the desired mode. If mode is not specified, cycles through the available modes.""" if not mode: new_idx = ( self.valid_modes.index(self.mode) + 1 ) % \ len(self.valid_modes) self.mode = self.valid_modes[new_idx] elif mode not in self.valid_modes: raise ValueError, 'Unrecognized mode in FormattedTB: <'+mode+'>\n'\ 'Valid modes: '+str(self.valid_modes) else: self.mode = mode # include variable details only in 'Verbose' mode self.include_vars = (self.mode == self.valid_modes[2]) # some convenient shorcuts def plain(self): self.set_mode(self.valid_modes[0]) def context(self): self.set_mode(self.valid_modes[1]) def verbose(self): self.set_mode(self.valid_modes[2]) #---------------------------------------------------------------------------- class AutoFormattedTB(FormattedTB): """A traceback printer which can be called on the fly. It will find out about exceptions by itself. A brief example: AutoTB = AutoFormattedTB(mode = 'Verbose',color_scheme='Linux') try: ... except: AutoTB() # or AutoTB(out=logfile) where logfile is an open file object """ def __call__(self,etype=None,evalue=None,etb=None, out=None,tb_offset=None): """Print out a formatted exception traceback. Optional arguments: - out: an open file-like object to direct output to. - tb_offset: the number of frames to skip over in the stack, on a per-call basis (this overrides temporarily the instance's tb_offset given at initialization time. """ if out is None: out = Term.cerr if tb_offset is not None: tb_offset, self.tb_offset = self.tb_offset, tb_offset print >> out, self.text(etype, evalue, etb) self.tb_offset = tb_offset else: print >> out, self.text(etype, evalue, etb) self.debugger() def text(self,etype=None,value=None,tb=None,context=5,mode=None): if etype is None: etype,value,tb = sys.exc_info() self.tb = tb return FormattedTB.text(self,etype,value,tb,context=5,mode=mode) #--------------------------------------------------------------------------- # A simple class to preserve Nathan's original functionality. class ColorTB(FormattedTB): """Shorthand to initialize a FormattedTB in Linux colors mode.""" def __init__(self,color_scheme='Linux',call_pdb=0): FormattedTB.__init__(self,color_scheme=color_scheme, call_pdb=call_pdb) #---------------------------------------------------------------------------- # module testing (minimal) if __name__ == "__main__": def spam(c, (d, e)): x = c + d y = c * d foo(x, y) def foo(a, b, bar=1): eggs(a, b + bar) def eggs(f, g, z=globals()): h = f + g i = f - g return h / i print '' print '*** Before ***' try: print spam(1, (2, 3)) except: traceback.print_exc() print '' handler = ColorTB() print '*** ColorTB ***' try: print spam(1, (2, 3)) except: apply(handler, sys.exc_info() ) print '' handler = VerboseTB() print '*** VerboseTB ***' try: print spam(1, (2, 3)) except: apply(handler, sys.exc_info() ) print ''