The bdb module provides a framework for debuggers. You can use this to
create your own custom debuggers, as Example 11-3 shows.
To implement custom behavior, subclass the Bdb
class, and override the user methods (which are
called whenever the debugger stops). To control the debugger, use the
various set methods.
Example 11-3. Using the bdb Mdule
File: bdb-example-1.py
import bdb
import time
def spam(n):
j = 0
for i in range(n):
j = j + i
return n
def egg(n):
spam(n)
spam(n)
spam(n)
spam(n)
def test(n):
egg(n)
class myDebugger(bdb.Bdb):
run = 0
def user_call(self, frame, args):
name = frame.f_code.co_name or "<unknown>"
print "call", name, args
self.set_continue() # continue
def user_line(self, frame):
if self.run:
self.run = 0
self.set_trace() # start tracing
else:
# arrived at breakpoint
name = frame.f_code.co_name or "<unknown>"
filename = self.canonic(frame.f_code.co_filename)
print "break at", filename, frame.f_lineno, "in", name
print "continue..."
self.set_continue() # continue to next breakpoint
def user_return(self, frame, value):
name = frame.f_code.co_name or "<unknown>"
print "return from", name, value
print "continue..."
self.set_continue() # continue
def user_exception(self, frame, exception):
name = frame.f_code.co_name or "<unknown>"
print "exception in", name, exception
print "continue..."
self.set_continue() # continue
db = myDebugger()
db.run = 1
db.set_break("bdb-example-1.py", 7)
db.runcall(test, 1)
continue...
call egg None
call spam None
break at C:ematterlibrarybookdb-example-1.py 7 in spam
continue...
call spam None
break at C:ematterlibrarybookdb-example-1.py 7 in spam
continue...
call spam None
break at C:ematterlibrarybookdb-example-1.py 7 in spam
continue...
call spam None
break at C:ematterlibrarybookdb-example-1.py 7 in spam
continue.....................Content has been hidden....................
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