Mailing List Archive: 49091 messages
  • Home
  • Script library
  • AltME Archive
  • Mailing list
  • Articles Index
  • Site search

[REBOL] Re: new puzzle on sameness 1

From: rotenca:telvia:it at: 14-Feb-2003 16:00

> Hi, the solution of the puzzle is below, although I am not sure, that it > shows any properties of sameness:
I disagree. a2 is a reference to the same data referenced by a1 a3 is a reference to data which has the same abstract value of the data referenced by a1 When i change the data referenced by a1, a2 remain identical to a1, while a3 retain its old value, no more equal to a1. And given taht "two values are identical if they have equal state and every mutation affects them simultaneously", I conclude that both same? and identical? fail to distingue all identical values. Given and and I must add that the classification of changes in the previous text are incomplete: 1) some affect only one values (replacements) 2) some affect all occurrences (mutations) 3) some affect only some word occurrences (word-mutations) I must also add that there are diffentent kindes of occurrences definited with 2 and 3 I must also add that all rebol value of any datatype! referenced by words are word-mutable . I conclude that a function like identical? is undefined for some rebol values, because it receives its arguments as "abstraction" which do not include all the information needed to decide the identity ("two Rebol values are identical, if they are equivalent for every purpose"). I should do others checkes, but now i think that a function like identical? is only able to detect if two Rebol scalar value are strict-equal? or if two abstractions of Rebol scalar value are the same. This only works if abstractions are considered immutable by definition. --- Ciao Romano