Ivan Shmakov scripsit: > Given that the basic idea of hashing is to produce a key out of > the object’s /value/, the change of the value – and mutation > does just that – changes the hash.
Well, yes and no. SRFI 69 and other Scheme hash table frameworks support at least two kinds of hashing: hash by value and hash by identity. If you have a large tree structure made with pairs, and you want to keep ancillary information about some but not all of the pairs, an identity-based hash table will let you keep the information associated with *a particular pair*. Otherwise, if you had a tree like (a (b c) (b c)), then any information associated with the first (b c) would be overwritten if you associated information with the second (b c). This is quite independent of whether you ever mutate the tree or not. -- John Cowan http://www.ccil.org/~cowan co...@ccil.org As you read this, I don't want you to feel sorry for me, because, I believe everyone will die someday. --From a Nigerian-type scam spam _______________________________________________ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
