Andrew McDonagh schrieb: > Joachim Durchholz wrote: >> Chris Smith schrieb: >>> Joachim Durchholz <[EMAIL PROTECTED]> wrote: >>>> Sorry, I have to insist that it's not me who's stretching terms here. >>>> >>>> All textbook definitions that I have seen define a type as the >>>> set/operations/axioms triple I mentioned above. >>>> No mention of immutability, at least not in the definitions. >>> >>> The immutability comes from the fact (perhaps implicit in these >>> textbooks, or perhaps they are not really texts on formal type >>> theory) that types are assigned to expressions, >> >> That doesn't *define* what's a type or what isn't! >> >> If it's impossible to assign types to all expressions of a program in >> a language, that does mean that there's no useful type theory for the >> program, but it most definitely does not mean that there are no types >> in the program. >> I can still sensibly talk about sets of values, sets of allowable >> operations over each value, and about relationships between inputs and >> outputs of these operations. >> >> So programs have types, even if they don't have a static type system. >> Q.E.D. > > Of course not. Otherwise programs using dynamically typed systems > wouldnt exist.
I don't understand. Do you mean dynamic typing (aka runtime types)? > I haven't read all of this thread, I wonder, is the problem to do with > Class being mistaken for Type? (which is usually the issue) No, not at all. I have seen quite a lot beyond OO ;-) Regards, Jo -- http://mail.python.org/mailman/listinfo/python-list