in reply to Understanding use and require fully

the values would get lost on each time the required file got hit.

In What's the difference between require and use? 

    1)  do $file is like eval `cat $file`, except the former
    1.1: searches @INC and updates %INC.
    1.2: bequeaths an *unrelated* lexical scope on the eval'ed code.

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It is the unrelated bit; in the eval'ed code lexicals from the including code are not visible. Consider: 

# file foo.pl
print $var,"\n";

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# requiring code
$var = 'foo';
require 'foo.pl';

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prints foo whilst 
# requiring code
my $var = 'foo';
require 'foo.pl';

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does not. Also, a file is only required once, so constructs like 
our $var;
for $var ( qw(foo bar quux) ) {
    require 'foo.pl';
}

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won't work as you would expect, since only foo is printed: require on subsequent passes through the loop will just return 1 and not eval the code again.

See also use, require, do or what?

--shmem 

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

In Section Seekers of Perl Wisdom