I haven't checked the sources, but empirical evidence made it clear to me there is only one LVALUE object per lexical occurrance of 'substr'.

This means for example that while this works:

$x = \substr("blah", 1, 2);
$y = \substr("florp", 1, 3);
print "$$x $$y\n";
[download]

this will not:

sub substrref { \substr($_[0], $_[1], $_[2]) }
$x = substrref("blah", 1, 2);
$y = substrref("florp", 1, 3);
print "$$x $$y\n";
[download]

The work-around is to create a new lexical occurrance each time, by using eval STRING:

sub substrref { eval '\substr($_[0], $_[1], $_[2])' }
$x = substrref("blah", 1, 2);
$y = substrref("florp", 1, 3);
print "$$x $$y\n";
[download]

I hope this helps :-)

(The obvious real solution is that substr() should check the refcount of the PVLV-object and create a fresh one if someone is still holding a reference to the previous one)

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