Let function substr return a lvalue which could be store in a (new type of?) scalar. The lvalue can then be used together with =~.

That is already possible. 

C:\test>p1
$s = 'This is a string (with a bit in the middle) before the string en
+ds';;
$r = \substr $s, 18, 24;;

print $$r;;
with a bit in the middle

$$r =~ s[([a-z]+)][\U$1]g;;

print $s;;
This is a string (WITH A BIT IN THE MIDDLE) before the string ends

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In reply to Re: Setting end position for the regexp engine by BrowserUk
in thread Setting end position for the regexp engine by bojinlund

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