* [Ada] implement many new Ada 2005 features @ 2005-02-14 8:42 Hyman Rosen 2005-02-15 13:30 ` Marin David Condic 2005-02-17 23:00 ` Randy Brukardt 0 siblings, 2 replies; 15+ messages in thread From: Hyman Rosen @ 2005-02-14 8:42 UTC (permalink / raw) For those c.l.a. readers who don'tregularly follow the gcc-patches mailing list of gnu.gcc.org, check the following message: <http://gcc.gnu.org/ml/gcc-patches/2005-02/msg00420.html> Good news for Ada devotees, and it should give pause to one or two overly ambitious n.g. members who are bent on writing their own Ada compilers from scratch :-) ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-14 8:42 [Ada] implement many new Ada 2005 features Hyman Rosen @ 2005-02-15 13:30 ` Marin David Condic 2005-02-16 8:01 ` Hyman Rosen 2005-02-17 23:00 ` Randy Brukardt 1 sibling, 1 reply; 15+ messages in thread From: Marin David Condic @ 2005-02-15 13:30 UTC (permalink / raw) Hyman Rosen wrote: > For those c.l.a. readers who don'tregularly follow the gcc-patches > mailing list of gnu.gcc.org, check the following message: > <http://gcc.gnu.org/ml/gcc-patches/2005-02/msg00420.html> > Good to see that there is an Ada 2005 implementation well under way and making good progress. > Good news for Ada devotees, and it should give pause to one or two > overly ambitious n.g. members who are bent on writing their own Ada > compilers from scratch :-) Depends on the reason for wanting to write your own compiler. If you want to learn about compiler theory or perhaps try out some techniques not done in other implementations or target some machine nobody else is interested in supporting, then you might have a really good reason. If the objective is to supplant the "industry leader" (is that fair to say of Gnat?) then one needs to be really well financed and have some anticipated features/benefits that will make the end product better. Without a "better idea" and lots of resources, I wouldn't try to overtake Gnat, et alia. But hobbies, education, theory testing, etc. are all good enough reasons to go for it. MDC -- ====================================================================== Marin David Condic I work for: http://www.belcan.com/ My project is: http://www.jsf.mil/NSFrames.htm Send Replies To: m o d c @ a m o g c n i c . r "'Shut up,' he explained." -- Ring Lardner ====================================================================== ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-15 13:30 ` Marin David Condic @ 2005-02-16 8:01 ` Hyman Rosen 2005-02-16 13:13 ` Marin David Condic 0 siblings, 1 reply; 15+ messages in thread From: Hyman Rosen @ 2005-02-16 8:01 UTC (permalink / raw) Marin David Condic wrote: > Depends on the reason for wanting to write your own compiler. Not really. After man-decades of effort, there are still little corner cases in GNAT that need fixing up. Someone starting over from scratch is going to lose the benefit of all that experience and will have to rediscover all those little problems himself. That's why the temptation to rewrite a system is so pernicious. A lot of the knowledge lives in the code, and isn't documented anywhere else. Because of that, the rewriters begin with the thought that the new system will be cleaner and nicer than the old one. It's only later when the new system doesn't work that they discover all the things that the old system can do and the new one can't. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-16 8:01 ` Hyman Rosen @ 2005-02-16 13:13 ` Marin David Condic 2005-02-16 14:54 ` Robert A Duff 0 siblings, 1 reply; 15+ messages in thread From: Marin David Condic @ 2005-02-16 13:13 UTC (permalink / raw) I agree that with all the work that has gone into Gnat/gcc that one would have a hard time catching up. That's why I said if one wished to take over the market dominance owned by Gnat, et alia, one would need to be really well financed and truly have some better idea. But would you suggest that college level compiler classes not assign their students to go write a compiler? Probably not. Hence there is a reason someone might want to do so. "I want to learn about compilers and try out some interesting theories I have..." is a good reason to go write one. Taking over the market from "Coca Cola" would probably be a bad objective because of the cost & difficulty of actually succeeding. But then, Ada itself keeps tilting at that windmill so should we really be surprised? MDC Hyman Rosen wrote: > > Not really. After man-decades of effort, there are still little > corner cases in GNAT that need fixing up. Someone starting over > from scratch is going to lose the benefit of all that experience > and will have to rediscover all those little problems himself. > > That's why the temptation to rewrite a system is so pernicious. > A lot of the knowledge lives in the code, and isn't documented > anywhere else. Because of that, the rewriters begin with the > thought that the new system will be cleaner and nicer than the > old one. It's only later when the new system doesn't work that > they discover all the things that the old system can do and the > new one can't. -- ====================================================================== Marin David Condic I work for: http://www.belcan.com/ My project is: http://www.jsf.mil/NSFrames.htm Send Replies To: m o d c @ a m o g c n i c . r "'Shut up,' he explained." -- Ring Lardner ====================================================================== ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-16 13:13 ` Marin David Condic @ 2005-02-16 14:54 ` Robert A Duff 2005-02-17 12:35 ` Marin David Condic 2005-02-27 15:24 ` Colin Paul Gloster 0 siblings, 2 replies; 15+ messages in thread From: Robert A Duff @ 2005-02-16 14:54 UTC (permalink / raw) Marin David Condic <nobody@noplace.com> writes: > But would you suggest that college level compiler classes not assign > their students to go write a compiler? Probably not. ... An Ada compiler is probably not the best choice for a college course. ;-) - Bob ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-16 14:54 ` Robert A Duff @ 2005-02-17 12:35 ` Marin David Condic 2005-02-27 15:24 ` Colin Paul Gloster 1 sibling, 0 replies; 15+ messages in thread From: Marin David Condic @ 2005-02-17 12:35 UTC (permalink / raw) Yeah, maybe. Unless the course has a title like "Understanding the Ada Programming Language From A Compiler Theory Perspective..." I'm aware of a number of compiler courses that at one time or another had students implementing mini-Ada compilers. (Probably because the syntax is pretty clean for parsing purposes.) But the point wasn't to design a compiler theory class. It was to observe that if someone wants to go off and try implementing an Ada compiler for purposes of education or to try out some theories or simply because they find compiler implementation an interesting hobby - I say don't discourage them. It's a learning exercise that will change them - if not the world. I qualified the comment that if the goal was to supplant something like Gnat, then its tilting at windmills and not really likely to succeed. The effort might be better spent working on some interesting new direction for Gnat to go in. (Porting to new hardware, adding a new capability, etc.) MDC Robert A Duff wrote: > > An Ada compiler is probably not the best choice for a college course. ;-) > > - Bob -- ====================================================================== Marin David Condic I work for: http://www.belcan.com/ My project is: http://www.jsf.mil/NSFrames.htm Send Replies To: m o d c @ a m o g c n i c . r "'Shut up,' he explained." -- Ring Lardner ====================================================================== ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-16 14:54 ` Robert A Duff 2005-02-17 12:35 ` Marin David Condic @ 2005-02-27 15:24 ` Colin Paul Gloster 1 sibling, 0 replies; 15+ messages in thread From: Colin Paul Gloster @ 2005-02-27 15:24 UTC (permalink / raw) On Wed, 16 Feb 2005, Robert A Duff wrote: "Marin David Condic <nobody@noplace.com> writes: > But would you suggest that college level compiler classes not assign > their students to go write a compiler? Probably not. ... An Ada compiler is probably not the best choice for a college course. ;-)" For an entirely different reason a compilers lecturer I used to have had a problem with Ada: he believed that structural equivalence and compatiblity of types (i.e. weaktyping) was superior to strong typing. Yikes! ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-14 8:42 [Ada] implement many new Ada 2005 features Hyman Rosen 2005-02-15 13:30 ` Marin David Condic @ 2005-02-17 23:00 ` Randy Brukardt 2005-02-18 4:21 ` Ed Falis ` (2 more replies) 1 sibling, 3 replies; 15+ messages in thread From: Randy Brukardt @ 2005-02-17 23:00 UTC (permalink / raw) "Hyman Rosen" <hyrosen@mail.com> wrote in message news:VvZPd.21381$ya6.16171@trndny01... ... > Good news for Ada devotees, and it should give pause to one or two > overly ambitious n.g. members who are bent on writing their own Ada > compilers from scratch :-) Well, some of us have our own Ada compilers (Janus/Ada in my case), and I certainly hope that you are not advocating the elimination of all other Ada technology. I can't think of anything more certain to kill Ada than to have only one source for compilers - that would mean that one size would have to fit all, and that is unlikely to be true. Certainly, Janus/Ada is not going to compete in every environment with GNAT (it's certainly not suitable for hard real-time work, for instance), but it keeps alive techniques that have disappeared elsewhere: real generic code sharing, discontiguous objects (no allocate-the-max bs here), and so on. I wouldn't suggest that anyone start from scratch, though, because I've spent about 17 years of my life working on Janus/Ada (along with a number of other people), and that sort of investment is not something to undertake for most humans. And a compiler for the "easy" subset of Ada is unlikely to be interesting. Randy Brukardt ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-17 23:00 ` Randy Brukardt @ 2005-02-18 4:21 ` Ed Falis 2005-02-18 5:27 ` Larry Kilgallen 2005-02-27 15:33 ` Colin Paul Gloster 2 siblings, 0 replies; 15+ messages in thread From: Ed Falis @ 2005-02-18 4:21 UTC (permalink / raw) On Thu, 17 Feb 2005 17:00:16 -0600, Randy Brukardt <randy@rrsoftware.com> wrote: > Well, some of us have our own Ada compilers (Janus/Ada in my case), and I > certainly hope that you are not advocating the elimination of all other > Ada > technology. I can't think of anything more certain to kill Ada than to > have > only one source for compilers - that would mean that one size would have > to > fit all, and that is unlikely to be true. > > Certainly, Janus/Ada is not going to compete in every environment with > GNAT > (it's certainly not suitable for hard real-time work, for instance), but > it > keeps alive techniques that have disappeared elsewhere: real generic code > sharing, discontiguous objects (no allocate-the-max bs here), and so on. > > I wouldn't suggest that anyone start from scratch, though, because I've > spent about 17 years of my life working on Janus/Ada (along with a > number of > other people), and that sort of investment is not something to undertake > for > most humans. And a compiler for the "easy" subset of Ada is unlikely to > be > interesting. > > Randy Brukardt Hear! Hear! - Ed ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-17 23:00 ` Randy Brukardt 2005-02-18 4:21 ` Ed Falis @ 2005-02-18 5:27 ` Larry Kilgallen 2005-02-27 15:33 ` Colin Paul Gloster 2 siblings, 0 replies; 15+ messages in thread From: Larry Kilgallen @ 2005-02-18 5:27 UTC (permalink / raw) In article <rYSdnVHyaq8IvIjfRVn-3w@megapath.net>, "Randy Brukardt" <randy@rrsoftware.com> writes: > "Hyman Rosen" <hyrosen@mail.com> wrote in message > news:VvZPd.21381$ya6.16171@trndny01... > ... >> Good news for Ada devotees, and it should give pause to one or two >> overly ambitious n.g. members who are bent on writing their own Ada >> compilers from scratch :-) > > Well, some of us have our own Ada compilers (Janus/Ada in my case), and I > certainly hope that you are not advocating the elimination of all other Ada > technology. I can't think of anything more certain to kill Ada than to have > only one source for compilers - that would mean that one size would have to > fit all, and that is unlikely to be true. Consider the case of Mumps/M where the number of vendors was so reduced by vendors buying each other out that there is no longer an international standard due to lack of vendor interest. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-17 23:00 ` Randy Brukardt 2005-02-18 4:21 ` Ed Falis 2005-02-18 5:27 ` Larry Kilgallen @ 2005-02-27 15:33 ` Colin Paul Gloster 2005-02-28 22:31 ` Randy Brukardt 2 siblings, 1 reply; 15+ messages in thread From: Colin Paul Gloster @ 2005-02-27 15:33 UTC (permalink / raw) On Thu, 17 Feb 2005, Randy Brukardt wrote: "[..] Certainly, Janus/Ada is not going to compete in every environment with GNAT (it's certainly not suitable for hard real-time work, for instance), [..] [..]" However you do have the capability to port your cross development tools to target an 8bit processor don't you? Some decade I may want to fund a compiler for some poorly supported target I might be stuck with, and I might get worried if you could not do a realtime executive for me. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-27 15:33 ` Colin Paul Gloster @ 2005-02-28 22:31 ` Randy Brukardt 2005-02-28 23:58 ` tmoran 0 siblings, 1 reply; 15+ messages in thread From: Randy Brukardt @ 2005-02-28 22:31 UTC (permalink / raw) "Colin Paul Gloster" <Colin_Paul_Gloster@ACM.org> wrote in message news:Pine.WNT.4.62.0502271630490.-706617@PC3... > On Thu, 17 Feb 2005, Randy Brukardt wrote: > > "[..] > > Certainly, Janus/Ada is not going to compete in every environment with GNAT > (it's certainly not suitable for hard real-time work, for instance), [..] > > [..]" > > However you do have the capability to port your cross development tools to > target an 8bit processor don't you? Some decade I may want to fund a > compiler for some poorly supported target I might be stuck with, and I > might get worried if you could not do a realtime executive for me. Real-time, yes. Hard real-time, I don't think so. The primary issue is that hard real-time systems usually need strict control over memory management as well. Janus/Ada generally uses dynamic allocation (heap, that is) for anything not statically sized, which (because of code sharing) includes function calls and pretty much anything in generics. So writing sane Ada code that completely avoids dynamic allocation is nearly impossible with Janus/Ada, and that would make it inappropriate for some purposes. (We'll probably eliminate some of the dynamic cases from function calls when we implement extended return statements, and our optimizer already eliminates many more, but I don't think that the general issue will disappear. Of course, with enough money, anything is possible...) Randy Brukardt. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-28 22:31 ` Randy Brukardt @ 2005-02-28 23:58 ` tmoran 2005-03-01 9:08 ` Vinzent 'Gadget' Hoefler 2005-03-01 10:14 ` Colin_Paul_Gloster 0 siblings, 2 replies; 15+ messages in thread From: tmoran @ 2005-02-28 23:58 UTC (permalink / raw) > Real-time, yes. Hard real-time, I don't think so. Of course with today's CPUs some things that used to be difficult to do in real time are now easy. (note Java) ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-28 23:58 ` tmoran @ 2005-03-01 9:08 ` Vinzent 'Gadget' Hoefler 2005-03-01 10:14 ` Colin_Paul_Gloster 1 sibling, 0 replies; 15+ messages in thread From: Vinzent 'Gadget' Hoefler @ 2005-03-01 9:08 UTC (permalink / raw) tmoran@acm.org wrote: >> Real-time, yes. Hard real-time, I don't think so. > Of course with today's CPUs some things that used to be difficult to > do in real time are now easy. (note Java) Still doesn't qualify for "hard real-time". The notion of "immortal memory" and no heap realtime threads" didn't go into the RTSJ just for fun. Vinzent. -- worst case: The wrong assumption there actually is one. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [Ada] implement many new Ada 2005 features 2005-02-28 23:58 ` tmoran 2005-03-01 9:08 ` Vinzent 'Gadget' Hoefler @ 2005-03-01 10:14 ` Colin_Paul_Gloster 1 sibling, 0 replies; 15+ messages in thread From: Colin_Paul_Gloster @ 2005-03-01 10:14 UTC (permalink / raw) References: <1ZqdnRrgeMe3Br7fRVn-qg@megapath.net> <ScSdnSWjepOPLb7fRVn-hQ@comcast.com> Note that aicas's work on developing realtime Java is being based on RAVENSCAR. The heavyweight processors needed for QNX and VxWorks do not seem to provide hard enough guarantees to Pete Fenelon's satisfaction ( news:news:4arvuc.h91.ln@fenelon.com , "Re: OS9, hard or soft RTOS?", Wed, 16 Feb 2005 16:10:44 +0000) (same goes for OS9 by the way). Which makes one wonder why someone in the Canadian Space AGency ranked QNX as the best RTOS for the Canadian Space Agency's needs after surveying approximately 48 RTOSes (presented at DASIA 2003)? ^ permalink raw reply [flat|nested] 15+ messages in thread
end of thread, other threads:[~2005-03-01 10:14 UTC | newest] Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2005-02-14 8:42 [Ada] implement many new Ada 2005 features Hyman Rosen 2005-02-15 13:30 ` Marin David Condic 2005-02-16 8:01 ` Hyman Rosen 2005-02-16 13:13 ` Marin David Condic 2005-02-16 14:54 ` Robert A Duff 2005-02-17 12:35 ` Marin David Condic 2005-02-27 15:24 ` Colin Paul Gloster 2005-02-17 23:00 ` Randy Brukardt 2005-02-18 4:21 ` Ed Falis 2005-02-18 5:27 ` Larry Kilgallen 2005-02-27 15:33 ` Colin Paul Gloster 2005-02-28 22:31 ` Randy Brukardt 2005-02-28 23:58 ` tmoran 2005-03-01 9:08 ` Vinzent 'Gadget' Hoefler 2005-03-01 10:14 ` Colin_Paul_Gloster
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