pdb.py 12.8 KB
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#! /usr/bin/env python
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# pdb.py -- finally, a Python debugger!
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# (See pdb.doc for documentation.)
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import string
import sys
import linecache
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import cmd
import bdb
import repr
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# Interaction prompt line will separate file and call info from code
# text using value of line_prefix string.  A newline and arrow may
# be to your liking.  You can set it once pdb is imported using the
# command "pdb.line_prefix = '\n% '".
# line_prefix = ': '	# Use this to get the old situation back
line_prefix = '\n-> '	# Probably a better default

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class Pdb(bdb.Bdb, cmd.Cmd):
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	def __init__(self):
		bdb.Bdb.__init__(self)
		cmd.Cmd.__init__(self)
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		self.prompt = '(Pdb) '
	
	def reset(self):
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		bdb.Bdb.reset(self)
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		self.forget()
	
	def forget(self):
		self.lineno = None
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		self.stack = []
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		self.curindex = 0
		self.curframe = None
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	def setup(self, f, t):
		self.forget()
		self.stack, self.curindex = self.get_stack(f, t)
		self.curframe = self.stack[self.curindex][0]
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	# Override Bdb methods (except user_call, for now)
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	def user_line(self, frame):
		# This function is called when we stop or break at this line
		self.interaction(frame, None)
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	def user_return(self, frame, return_value):
		# This function is called when a return trap is set here
		frame.f_locals['__return__'] = return_value
		print '--Return--'
		self.interaction(frame, None)
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	def user_exception(self, frame, (exc_type, exc_value, exc_traceback)):
		# This function is called if an exception occurs,
		# but only if we are to stop at or just below this level
		frame.f_locals['__exception__'] = exc_type, exc_value
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		if type(exc_type) == type(''):
			exc_type_name = exc_type
		else: exc_type_name = exc_type.__name__
		print exc_type_name + ':', repr.repr(exc_value)
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		self.interaction(frame, exc_traceback)
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	# General interaction function
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	def interaction(self, frame, traceback):
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		self.setup(frame, traceback)
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		self.print_stack_entry(self.stack[self.curindex])
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		self.cmdloop()
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		self.forget()
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	def default(self, line):
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		if line[:1] == '!': line = line[1:]
		locals = self.curframe.f_locals
		globals = self.curframe.f_globals
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		globals['__privileged__'] = 1
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		try:
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			code = compile(line + '\n', '<stdin>', 'single')
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			exec code in globals, locals
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		except:
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			t, v = sys.exc_info()[:2]
			if type(t) == type(''):
				exc_type_name = t
			else: exc_type_name = t.__name__
			print '***', exc_type_name + ':', v
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	# Command definitions, called by cmdloop()
	# The argument is the remaining string on the command line
	# Return true to exit from the command loop 
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	do_h = cmd.Cmd.do_help
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	def do_break(self, arg):
		if not arg:
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			print self.get_all_breaks() # XXX
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			return
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		# Try line number as argument
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		try:
			arg = eval(arg, self.curframe.f_globals,
				   self.curframe.f_locals)
		except:
			print '*** Could not eval argument:', arg
			return

		# Check for condition
		try: arg, cond = arg
		except: arg, cond = arg, None

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		try:	
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			lineno = int(arg)
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			filename = self.curframe.f_code.co_filename
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		except:
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			# Try function name as the argument
			try:
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				func = arg
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				if hasattr(func, 'im_func'):
					func = func.im_func
				code = func.func_code
			except:
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				print '*** The specified object',
				print 'is not a function', arg
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				return
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			lineno = code.co_firstlineno
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			filename = code.co_filename

		# now set the break point
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		err = self.set_break(filename, lineno, cond)
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		if err: print '***', err
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	do_b = do_break
	
	def do_clear(self, arg):
		if not arg:
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			try:
				reply = raw_input('Clear all breaks? ')
			except EOFError:
				reply = 'no'
			reply = string.lower(string.strip(reply))
			if reply in ('y', 'yes'):
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				self.clear_all_breaks()
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			return
		try:
			lineno = int(eval(arg))
		except:
			print '*** Error in argument:', `arg`
			return
		filename = self.curframe.f_code.co_filename
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		err = self.clear_break(filename, lineno)
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		if err: print '***', err
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	do_cl = do_clear # 'c' is already an abbreviation for 'continue'
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	def do_where(self, arg):
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		self.print_stack_trace()
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	do_w = do_where
	
	def do_up(self, arg):
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		if self.curindex == 0:
			print '*** Oldest frame'
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		else:
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			self.curindex = self.curindex - 1
			self.curframe = self.stack[self.curindex][0]
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			self.print_stack_entry(self.stack[self.curindex])
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			self.lineno = None
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	do_u = do_up
	
	def do_down(self, arg):
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		if self.curindex + 1 == len(self.stack):
			print '*** Newest frame'
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		else:
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			self.curindex = self.curindex + 1
			self.curframe = self.stack[self.curindex][0]
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			self.print_stack_entry(self.stack[self.curindex])
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			self.lineno = None
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	do_d = do_down
	
	def do_step(self, arg):
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		self.set_step()
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		return 1
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	do_s = do_step
	
	def do_next(self, arg):
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		self.set_next(self.curframe)
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		return 1
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	do_n = do_next
	
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	def do_return(self, arg):
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		self.set_return(self.curframe)
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		return 1
	do_r = do_return
	
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	def do_continue(self, arg):
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		self.set_continue()
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		return 1
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	do_c = do_cont = do_continue
	
	def do_quit(self, arg):
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		self.set_quit()
		return 1
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	do_q = do_quit
	
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	def do_args(self, arg):
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		if self.curframe.f_locals.has_key('__args__'):
			print `self.curframe.f_locals['__args__']`
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		else:
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			print '*** No arguments?!'
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	do_a = do_args
	
	def do_retval(self, arg):
		if self.curframe.f_locals.has_key('__return__'):
			print self.curframe.f_locals['__return__']
		else:
			print '*** Not yet returned!'
	do_rv = do_retval
	
	def do_p(self, arg):
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		self.curframe.f_globals['__privileged__'] = 1
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		try:
			value = eval(arg, self.curframe.f_globals, \
					self.curframe.f_locals)
		except:
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			t, v = sys.exc_info()[:2]
			if type(t) == type(''):
				exc_type_name = t
			else: exc_type_name = t.__name__
			print '***', exc_type_name + ':', `v`
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			return
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		print `value`

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	def do_list(self, arg):
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		self.lastcmd = 'list'
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		last = None
		if arg:
			try:
				x = eval(arg, {}, {})
				if type(x) == type(()):
					first, last = x
					first = int(first)
					last = int(last)
					if last < first:
						# Assume it's a count
						last = first + last
				else:
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					first = max(1, int(x) - 5)
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			except:
				print '*** Error in argument:', `arg`
				return
		elif self.lineno is None:
			first = max(1, self.curframe.f_lineno - 5)
		else:
			first = self.lineno + 1
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		if last == None:
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			last = first + 10
		filename = self.curframe.f_code.co_filename
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		breaklist = self.get_file_breaks(filename)
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		try:
			for lineno in range(first, last+1):
				line = linecache.getline(filename, lineno)
				if not line:
					print '[EOF]'
					break
				else:
					s = string.rjust(`lineno`, 3)
					if len(s) < 4: s = s + ' '
					if lineno in breaklist: s = s + 'B'
					else: s = s + ' '
					if lineno == self.curframe.f_lineno:
						s = s + '->'
					print s + '\t' + line,
					self.lineno = lineno
		except KeyboardInterrupt:
			pass
	do_l = do_list
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	def do_whatis(self, arg):
		try:
			value = eval(arg, self.curframe.f_globals, \
					self.curframe.f_locals)
		except:
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			t, v = sys.exc_info()[:2]
			if type(t) == type(''):
				exc_type_name = t
			else: exc_type_name = t.__name__
			print '***', exc_type_name + ':', `v`
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			return
		code = None
		# Is it a function?
		try: code = value.func_code
		except: pass
		if code:
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			print 'Function', code.co_name
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			return
		# Is it an instance method?
		try: code = value.im_func.func_code
		except: pass
		if code:
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			print 'Method', code.co_name
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			return
		# None of the above...
		print type(value)
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	# Print a traceback starting at the top stack frame.
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	# The most recently entered frame is printed last;
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	# this is different from dbx and gdb, but consistent with
	# the Python interpreter's stack trace.
	# It is also consistent with the up/down commands (which are
	# compatible with dbx and gdb: up moves towards 'main()'
	# and down moves towards the most recent stack frame).
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	def print_stack_trace(self):
		try:
			for frame_lineno in self.stack:
				self.print_stack_entry(frame_lineno)
		except KeyboardInterrupt:
			pass
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	def print_stack_entry(self, frame_lineno, prompt_prefix=line_prefix):
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		frame, lineno = frame_lineno
		if frame is self.curframe:
			print '>',
		else:
			print ' ',
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		print self.format_stack_entry(frame_lineno, prompt_prefix)
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	# Help methods (derived from pdb.doc)

	def help_help(self):
		self.help_h()

	def help_h(self):
		print """h(elp)
	Without argument, print the list of available commands.
	With a command name as argument, print help about that command
	"help pdb" pipes the full documentation file to the $PAGER
	"help exec" gives help on the ! command"""

	def help_where(self):
		self.help_w()

	def help_w(self):
		print """w(here)
	Print a stack trace, with the most recent frame at the bottom.
	An arrow indicates the "current frame", which determines the
	context of most commands."""

	def help_down(self):
		self.help_d()

	def help_d(self):
		print """d(own)
	Move the current frame one level down in the stack trace
	(to an older frame)."""

	def help_up(self):
		self.help_u()

	def help_u(self):
		print """u(p)
	Move the current frame one level up in the stack trace
	(to a newer frame)."""

	def help_break(self):
		self.help_b()

	def help_b(self):
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		print """b(reak) [lineno | function] [, "condition"]
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	With a line number argument, set a break there in the current
	file.  With a function name, set a break at the entry of that
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	function.  Without argument, list all breaks.  If a second
	argument is present, it is a string specifying an expression
	which must evaluate to true before the breakpoint is honored.
	"""
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	def help_clear(self):
		self.help_cl()

	def help_cl(self):
		print """cl(ear) [lineno]
	With a line number argument, clear that break in the current file.
	Without argument, clear all breaks (but first ask confirmation)."""

	def help_step(self):
		self.help_s()

	def help_s(self):
		print """s(tep)
	Execute the current line, stop at the first possible occasion
	(either in a function that is called or in the current function)."""

	def help_next(self):
		self.help_n()

	def help_n(self):
		print """n(ext)
	Continue execution until the next line in the current function
	is reached or it returns."""

	def help_return(self):
		self.help_r()

	def help_r(self):
		print """r(eturn)
	Continue execution until the current function returns."""

	def help_continue(self):
		self.help_c()

	def help_cont(self):
		self.help_c()

	def help_c(self):
		print """c(ont(inue))
	Continue execution, only stop when a breakpoint is encountered."""

	def help_list(self):
		self.help_l()

	def help_l(self):
		print """l(ist) [first [,last]]
	List source code for the current file.
	Without arguments, list 11 lines around the current line
	or continue the previous listing.
	With one argument, list 11 lines starting at that line.
	With two arguments, list the given range;
	if the second argument is less than the first, it is a count."""

	def help_args(self):
		self.help_a()

	def help_a(self):
		print """a(rgs)
	Print the argument list of the current function."""

	def help_p(self):
		print """p expression
	Print the value of the expression."""

	def help_exec(self):
		print """(!) statement
	Execute the (one-line) statement in the context of
	the current stack frame.
	The exclamation point can be omitted unless the first word
	of the statement resembles a debugger command.
	To assign to a global variable you must always prefix the
	command with a 'global' command, e.g.:
	(Pdb) global list_options; list_options = ['-l']
	(Pdb)"""

	def help_quit(self):
		self.help_q()

	def help_q(self):
		print """q(uit)	Quit from the debugger.
	The program being executed is aborted."""

	def help_pdb(self):
		help()

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# Simplified interface

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def run(statement, globals=None, locals=None):
	Pdb().run(statement, globals, locals)

def runeval(expression, globals=None, locals=None):
	return Pdb().runeval(expression, globals, locals)
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def runctx(statement, globals, locals):
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	# B/W compatibility
	run(statement, globals, locals)
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def runcall(*args):
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	return apply(Pdb().runcall, args)
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def set_trace():
	Pdb().set_trace()
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# Post-Mortem interface

def post_mortem(t):
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	p = Pdb()
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	p.reset()
	while t.tb_next <> None: t = t.tb_next
	p.interaction(t.tb_frame, t)

def pm():
	import sys
	post_mortem(sys.last_traceback)


# Main program for testing

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TESTCMD = 'import x; x.main()'
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def test():
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	run(TESTCMD)
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# print help
def help():
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	import os
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	for dirname in sys.path:
		fullname = os.path.join(dirname, 'pdb.doc')
		if os.path.exists(fullname):
			sts = os.system('${PAGER-more} '+fullname)
			if sts: print '*** Pager exit status:', sts
			break
	else:
		print 'Sorry, can\'t find the help file "pdb.doc"',
		print 'along the Python search path'
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# When invoked as main program, invoke the debugger on a script
if __name__=='__main__':
	import sys
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	import os
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	if not sys.argv[1:]:
		print "usage: pdb.py scriptfile [arg] ..."
		sys.exit(2)

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	filename = sys.argv[1]	# Get script filename

	del sys.argv[0]		# Hide "pdb.py" from argument list
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	# Insert script directory in front of module search path
	sys.path.insert(0, os.path.dirname(filename))
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	run('execfile(' + `filename` + ')', {'__name__': '__main__'})