block scope?
MRAB
google at mrabarnett.plus.com
Sat Apr 7 20:54:42 EDT 2007
On Apr 7, 8:50 am, James Stroud <jstr... at mbi.ucla.edu> wrote:
> Paul Rubin wrote:
> > John Nagle <n... at animats.com> writes:
> >> In a language with few declarations, it's probably best not to
> >> have too many different nested scopes. Python has a reasonable
> >> compromise in this area. Functions and classes have a scope, but
> >> "if" and "for" do not. That works adequately.
>
> > I think Perl did this pretty good. If you say "my $i" that declares
> > $i to have block scope, and it's considered good practice to do this,
> > but it's not required. You can say "for (my $i=0; $i < 5; $i++) { ... }"
> > and that gives $i the same scope as the for loop. Come to think of it
> > you can do something similar in C++.
>
> How then might one define a block? All lines at the same indent level
> and the lines nested within those lines?
>
> i = 5
> for my i in xrange(4):
> if i: # skips first when i is 0
> my i = 100
> if i:
> print i # of course 100
> break
> print i # i is between 0 & 3 here
> print i # i is 5 here
>
> Doesn't leave a particularly bad taste in one's mouth, I guess (except
> for the intended abuse).
>
How about something like this instead:
i = 5
block:
for i in xrange(4):
if i: # skips first when i is 0
block:
i = 100
if i:
print i # of course 100
break
print i # i is between 0 & 3 here
print i # i is 5 here
Any variable that's assigned to within a block would be local to that
block, as it is in functions.
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