On Feb 10, 2019, at 1:05 PM, John Rose <john.r.r...@oracle.com> wrote: > > 3. The infinite set should not be just the cyclic repetition > of some seed string, like a single quote character. This > is why the word "non-periodic" appears above In the > periodic case (alone) there are some strings which just barely > miss being quotable, because you can't tell when the strong > open quote ends and the string body begins. So the scheme > of repeating a quote character "enough times" just barely > misses being a proper strong quote scheme.
P.S. For those eagle-eyed and mathematically inclined: Periodicity is not exactly the right condition to avoid. The condition to avoid is more like every open-quote is an initial substring of another open-quote, in the infinite set of open-quotes. For example, initial finite sequences of the digits of pi would fail to be a set of strong quotes. Such cases are easy to avoid once periodicity has been eliminated.
