(FYI, offline comment with my reply.) Begin forwarded message:
From: John Rose <john.r.r...@oracle.com> Subject: Re: An example of substituability test that is recursive Date: January 31, 2019 at 11:48:53 AM PST To: Palo Marton <palo.mar...@gmail.com> Cc: Rémi Forax <fo...@univ-mlv.fr>, Brian Goetz <brian.go...@oracle.com> On Jan 31, 2019, at 11:28 AM, Palo Marton <palo.mar...@gmail.com <mailto:palo.mar...@gmail.com>> wrote: > > (Sorry to bother you with direct email, I'm only on observer list...) > > Here is a possible solution for "infinitive recursion/DDOS" problem with cmp: > Make values that might be affected by this problem singletons on the heap, so > compare function will be just fast pointer comparison (but at the cost of > much slower creation). > > Larger values will likely be on the heap anyway, so this will just add > another "way" of how values are stored. > 1) flattened > 2) heap > 3) heap+forced singleton > > Palo Not bad. By forced singleton I think you mean a structural intern, kind of like string interning? (Long ago for lists it was called hash-consing.) The whole point of forcing subst into acmp is to create a virtual emulation of such semantics. So we could switch implementation tactics for problem spots like polymorphic value fields. — John
