It was pointed out to me after I wrote the text in an earlier perldelta
that this one is extracted from, that it is extremely unlikely to run
out of memory; I had not bothered to really do the math.
would generate two hashes. Any probes in one instance would be unknown
to the other, and the hashes could expand separately to be quite large
if the regular expression were used on many different widely-separated
-code points. This can lead to running out of memory in extreme cases.
+code points.
Now, however, there is just one hash shared by all instances of a given
property. This means that if C<\p{foo}> is matched against "A" in one
regular expression in a thread, the result will be known immediately to