TypeError: unsubscriptable object.

[Terry Reedy]

"Balaji" <balaji at email.arizona.edu> wrote in message
news:494182a9.0405211340.49873a72 at posting.google.com...
> class Stack:
>
> def __init__(self,expr):

Note: tabs get eaten by some newsreaders.

> self.stackP=[]
> self.stackF=1
...
> def peekF(self):
> rval = 0 # useless line
> rval= self.stackF[-1]
> return rval
# return self.stackF[-1] would be easier to read

See the potential problem?  (If not, add
'print type(self.stackF)' to the top of this function.)

> def stackManagement(self,expr):
...
>     self.a+= self.peekF()

which now seems quite possible.
...
> s.stackManagement(e1)
> ----------------------------------------------
> I'm getting the following error TypeError: unsubscriptable object...

which means you tried to subscript an unsubscriptable object

> Traceback (most recent call last):
>   File "<stdin>", line 1, in ?
>   File "generation.py", line 175, in stackManagement
>     self.stackManagement(expr.left)
>   File "generation.py", line 176, in stackManagement
>     self.stackManagement(expr.right)
>   File "generation.py", line 199, in stackManagement
>     self.a+= self.peekF()
>   File "generation.py", line 168, in peekF
>     rval= self.stackF[-1]

in the line immediately above.

Terry J. Reedy