The Unicode conformance clauses, in TUS 4.0 section 3.2, are written in terms of what "A process" may or may not do, sometimes in relation to "another process". But there doesn't seem to be a definition, either on this section or in the glossary, of "process". Is this to be understood in a general non-technical sense, or in some specific technical sense? What makes "a process" distinct from "another process"? Are two instances carrying out the same function to be considered the same process or distinct processes?As there hasn't been a rush of on-list responses to this one, and partly in reply to the one off-list response, let me clarify the issue I am have in mind.
Instance A of a program P, version X, writes a Unicode character string S, in a particular normalisation form, to a storage medium Z. Some time later (maybe seconds, maybe years) instance B of version Y of that same program P reads that string from the same storage medium. For the purposes of Unicode conformance, are instances A and B to be considered one process or separate processes?
Conformance clause C9 states that "no process can assume that another process will make a distinction between two different, but canonical-equivalent character sequences", which implies that no process can assume that another process has correctly normalised any character sequence. So, if instances A and B are considered separate processes, B is not permitted to assume that the string S has been correctly normalised - even if in fact it is known that all strings on medium Z have been written by program P and that all versions of program P write strings in a particular normalisation form.
Also, can the storage medium Z be considered a process? Or can low-level transformations of the data, e.g. defragmentation, backup and compression, which are invisible to the program P be considered processes? If so, these processes are permitted to transform S into a canonically equivalent form; and so instance B of program P is not permitted to assume that the string it reads from Z is in the same normalisation form as the string written by instance A.
The potential implication is that it is non-conformant to rely on normalisation stability.
-- Peter Kirk [EMAIL PROTECTED] (personal) [EMAIL PROTECTED] (work) http://www.qaya.org/
