Using "pos() = $new_pos" does not work during the matching process.

That is also wrong. pos works in a substitution expression just like it does outside a substitution expression. Had you checked, you would have seen that lvalue pos does in fact change the var's pos when used in the substitution expression. 

$ perl -E'my $x="abc"; $x=~s/./say pos($x); pos($x)=2; say pos($x)/e;'
0
2

[download]

s/// simply doesn't care that you changed it. Like I've already explained, it simply doesn't make any sense for s/// to check if the string's pos has changed. Why are you still asking about this?

In reply to Re^8: Using pos() inside regexp (no /e) by ikegami
in thread Using pos() inside regexp by braveghost

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