Re^3: Scalar Value Not Available To Subroutine

[BrowserUk]

in reply to Re^2: Scalar Value Not Available To Subroutine
in thread Scalar Value Not Available To Subroutine

Seems so. Effectively, the loop variable has no relationship with any pre-existing variable with the same name:

my $i; 
for $i ( 1..10 ){ 
    1; 
}; 
print $i };;
Use of uninitialized value $i in print at (eval 9) line 1, <STDIN> lin
+e 1.

I believe it is a throw-over from pre-lexical Perl.

I've often wished (and occasionally argued in favour of), that for didn't localise pre-existing, lexical loop variables.

It makes for messy workarounds to the situation where a counting loop can exit early conditionally, and you want to know how far it counted:

my $i;
for $i ( 1 .. $N ) {
    last if <SOMECOND>;
    ...
}
## Here we have no way of knowing if we took an early exit;
## thus necessitating additional, unnecessary complexity to retain or 
+discover that.

[ikegami]

Effectively, the loop variable has no relationship with any pre-existing variable with the same name:

Same goes for local, fyi.

>perl -E"say 0+\$x; local $x; say 0+\$x;"
4885852
2403948

I've often wished (and occasionally argued in favour of), that for didn't localise pre-existing, lexical loop variables.

It would be useful and intuitive. It would drastically change the behaviour of the following, though

for $lex (...) {
   push @f, sub { ... $lex ... };
}

As it is now, I never use a pre-existing var.