On Mar 29, 6:34 pm, MRAB <pyt...@mrabarnett.plus.com> wrote: > LX wrote: > > Hi all, I have a question about decorators. I would like to use them > > for argument checking, and pre/post conditions. However, I don't want > > the additional overhead when I run in non-debug mode. I could do > > something like this, using a simple trace example. > > > @decorator > > def pass_decorator(f, *args, **kw): # what about the slow-down that > > incurs when using pass_decorator? > > return f(*args, **kw) > > > @decorator > > def trace_decorator(f, *args, **kw): > > print "calling %s with args %s, %s" % (f.func_name, args, kw) > > return f(*args, **kw) > > > trace_enable_flag = False #__debug__ > > trace = trace_decorator if trace_enable_flag else pass_decorator > > > Trouble is, there is still an additional encapsulating function call. > > Is there any way to eliminate the extra function call altogether? > > Thanks in advance! > > I think you have misunderstood certain details about decorators. > > This code with a decorator: > > �...@decorator > def hello(): > print "hello world" > > basically does this: > > def hello(): > print "hello world" > hello = decorator(hello) > > so your non-decorator just needs to return the function it was passed: > > def pass_decorator(func): > return func > > and your trace decorator would be something like this: > > def trace_decorator(func): > def show(*args, **kwargs): > print "calling %s with args %s, %s" % (func.func_name, > args, kwargs) > result = func(*args, **kwargs) > print "returning %s from %s" % (result, func.func_name) > return result > return show
Sure, but during runtime, pass_decorator will still be called, even though it doesn't do anything. I am wondering if I can disable this additional function call at non-debug runtime. In other words, I want the calling stack to contain no decorator at all, not even pass_decorator. I should mention that, in my code, the symbol "decorator" is imported from Michele Simionato's decorator.py file. -- http://mail.python.org/mailman/listinfo/python-list
