On Wed, 2008-01-30 at 07:40 -0600, Aaron Konstam wrote: > The following seems like an bug in python in both f7 and f8 but I would > like input before I post a bugzilla. It seems the exception handler > cannot trap the TypeError in python. > For example: > def plus(a,b): > try: > return(a+b) > except TypeError: > return None > > If we define plus as above and call it with: plus(3,) we should get > nothing returned. Instead we get: > Traceback (most recent call last): > File "./calculator", line 47, in <module> > exec("register=op[tokens[0]](register)") > File "<string>", line 1, in <module> > TypeError: plus() takes exactly 2 arguments (1 given) > > This seems like a bug. An ideas out there? > -- > ======================================================================= > Please keep your hands off the secretary's reproducing equipment. > ======================================================================= > Aaron Konstam telephone: (210) 656-0355 e-mail: akonstam(a)sbcglobal.net > If I remember right, the exception is occurring before the actual call into "plus()." Try: plus(3,"My String"); and you should see the TypeError.

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On Wed, 2008-01-30 at 19:34 +0530, Anoop Chandran wrote: > On Jan 30, 2008 7:28 PM, Mark C. Allman <mcallman(a)allmanpc.com&gt; wrote: > > On Wed, 2008-01-30 at 07:40 -0600, Aaron Konstam wrote: > > The following seems like an bug in python in both f7 and f8 > but I would > > like input before I post a bugzilla. It seems the exception > handler > > cannot trap the TypeError in python. > > For example: > > def plus(a,b): > > try: > > return(a+b) > > except TypeError: > > return None > > > > If we define plus as above and call it with: plus(3,) we > should get > > nothing returned. Instead we get: > > Traceback (most recent call last): > > File "./calculator", line 47, in <module> > > exec("register=op[tokens[0]](register)") > > File "<string>", line 1, in <module> > > TypeError: plus() takes exactly 2 arguments (1 given) > > > > This seems like a bug. An ideas out there? > > -- > > > > > If I remember right, the exception is occurring before the > actual call > into "plus()." Try: > plus(3,"My String"); > and you should see the TypeError. > > > try: > a = plus(3) > except TypeError: > a = 0 > print a > > Output should be 0. > > You are both correct but it still seems like a bug. Until you try to execute plus the system does not know that plus requires 2 arguments. But nevertheless a TypeError is generated so the exception handler should be triggered.

But you have given me further insight into the problem so I thank you all for that insight. The question is how do I do what I want to do; that is, check that the number of arguments to plus are correct? In the program in which I am using this construction the function executed and the arguments are generated dynamically so doing this checking is necessary.

>> def plus(a=None, b=None):

>> print plus(3, )

>> print plus(3)

>> print plus(3,2)

-- ======================================================================= Whether weary or unweary, O man, do not rest, Do not cease your single-handed struggle. Go on, do not rest. -- An old Gujarati hymn ======================================================================= Aaron Konstam telephone: (210) 656-0355 e-mail: akonstam(a)sbcglobal.net