Package's private parts and protected types
in [ADA]
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From: Jeffrey R. Carter on 8 Feb 2010 12:11 Robert A Duff wrote: > > C++ development started in 1979, and was named "C++" in 1983. > Ada development started in the late 70's (not sure exactly, > probably before 1979), and was named "Ada" before 1983. > So I think Ada slightly predates C++. "Green is Ada" occurred in 1980. > It also says C++ was standardized in 1998. Is that right? > I'm surprised it was so late... > Ada was first standardized in 1983. In 1980 (MIL-STD-1815, Ada 80). Ada will be 30 on 2010 Dec 10 (the 195th anniversary of the birth of Augusta Ada King, Countess of Lovelace, nee Byron). -- Jeff Carter "All citizens will be required to change their underwear every half hour. Underwear will be worn on the outside, so we can check." Bananas 29
From: Jean-Pierre Rosen on 8 Feb 2010 12:46 Robert A Duff a �crit : > "Dmitry A. Kazakov" <mailbox(a)dmitry-kazakov.de> writes: > What were they thinking?! The "task type T is..." syntax > is so obviously broken. The protected syntax just copied > that mistake, so it's not a mistake by itself. > That it is nice to have singletons that are clearly singletons, with a syntax close to the syntax for types. -- --------------------------------------------------------- J-P. Rosen (rosen(a)adalog.fr) Visit Adalog's web site at http://www.adalog.fr
From: Robert A Duff on 8 Feb 2010 15:39 Jean-Pierre Rosen <rosen(a)adalog.fr> writes: > Robert A Duff a �crit : >> "Dmitry A. Kazakov" <mailbox(a)dmitry-kazakov.de> writes: > >> What were they thinking?! The "task type T is..." syntax >> is so obviously broken. The protected syntax just copied >> that mistake, so it's not a mistake by itself. >> > That it is nice to have singletons that are clearly singletons, with a > syntax close to the syntax for types. Why on earth would you want an object decl to look like a type decl? The syntax for a variable decl is: X : T; If we want to use an anonymous array type, we say: X : array (...) of ...; -- unclearly a singleton? Hmm... So clearly the syntax for singleton tasks should be: My_Task : task ... -- seems clear to me rather than: task My_Task is ... And why are singletons allowed for some types but not others? If they make sense for arrays, tasks, and protected objects, then they make sense for records, etc. Sorry, but I stand by my opinion that this area is a mess! It's not hugely important, though. I guess I just value uniformity more than JDI. Note that syntactic uniformity makes the RM smaller, partly because of fewer syntax rules, but more importantly because non-syntax rules need to refer to syntactic categories by name. - Bob
From: Robert A Duff on 8 Feb 2010 15:44 "(see below)" <yaldnif.w(a)blueyonder.co.uk> writes: > Strangely, LIS, his ancestor of Ada, did not do this but had distinct, > separately compiled, interface, representation, and algorithm parts for the > LIS equivalent of packages. Interesting. I don't know anything about LIS. > I wonder what the rationale was for merging the first two. I suspect > compiler efficiency worries, valid at the time, that now are obsolete. I wonder, too. I don't buy the "compiler efficiency" worries. That might explain why private parts exist, but it doesn't explain why they can't be separately compiled (i.e. stored in separate source files). I'd eliminate them altogether, though. - Bob
From: Hibou57 (Yannick Duchêne) on 8 Feb 2010 16:50
On 8 fév, 18:46, Jean-Pierre Rosen <ro...(a)adalog.fr> wrote: > That it is nice to have singletons that are clearly singletons, with a > syntax close to the syntax for types. I agree with you about the singleton we can have with Protected Name .... End Name; But this is not the actual spot, which is Task type and Protected type are declared (not singleton). |