Introduction to Ada • Hacker News Board

Re: Introduction to Ada

#31

Post by Jtsummers » Thu, Sep 03, 2020, 5:45 AM UTC

wirrbel wrote: post #29

After having seen the C++ guidelines of the automobile industry i wish we'd just use Ada more..

I spent a lot of time circa 2009/2010 teaching myself Ada for similar reasons. I work in avionics systems (or used to, present job is not) and Ada is grossly underutilized. I’d be willing to wager half the bugs that I saw make it to the testers or, worse, the field would not have happened if we’d used Ada (and used the type system properly).

And these days, using Spark, even more bugs could be detected before compilation even succeeds. But no one wanted to use it at any of my jobs, and that knowledge has mostly atrophied from disuse.

Re: Introduction to Ada

#32

Post by WalterBright » Thu, Sep 03, 2020, 6:01 AM UTC

I always liked Ada, from my first reading around 1980 of MIL-STD-1815. Many of D's features were inspired by Ada.

Re: Introduction to Ada

#33

Post by e12e » Thu, Sep 03, 2020, 6:14 AM UTC

WalterBright wrote: post #32

I always liked Ada, from my first reading around 1980 of MIL-STD-1815. Many of D's features were inspired by Ada.

If you have the time, I'd love to hear a bit about why you ended up creating D, rather than writing an Ada compiler? (Seeing how you wrote a c++ compiler...).

Re: Introduction to Ada

#34

Post by aronpye » Thu, Sep 03, 2020, 6:36 AM UTC

What an ugly, unintuitive language. Are there any benefits to Ada over something like c++?

Re: Introduction to Ada

#35

Post by 1vuio0pswjnm7 » Thu, Sep 03, 2020, 6:53 AM UTC

The original open source Ada83 compiler that grew into GNAT for Ada95 was written in setl.

The author of GNU setl has said he would release the source, but we're still waiting. There are binaries here:

https://setl.org/setl/bin/

(No NetBSD ones though, forcing us to use emulation)

Ada reminds me of spitbol, and setl can be written in spitbol. R K Dewar's spitbol, written in a portable assembly language called MINIMAL, has been open-sourced. There's a version of setl written in spitbol, too. Hopefully we will have the source for setl one day.

The author's dissertation on setl is a favourite of mine:

https://web.archive.org/web/20060823004442if_/http://www.cs....

Re: Introduction to Ada

#36

Post by thesuperbigfrog » Thu, Sep 03, 2020, 6:57 AM UTC

aronpye wrote: post #34

What an ugly, unintuitive language. Are there any benefits to Ada over something like c++?

An advanced type system: https://learn.adacore.com/courses/intro-to-ada/chapters/stro...

Built-in concurrency and concurrent-safe data passing: https://learn.adacore.com/courses/intro-to-ada/chapters/task...

Design-by-contract programming: https://learn.adacore.com/courses/intro-to-ada/chapters/cont...

Provably safe programs if you use the SPARK subset of Ada: https://learn.adacore.com/courses/intro-to-spark/chapters/03...

Re: Introduction to Ada

#37

Post by WalterBright » Thu, Sep 03, 2020, 7:02 AM UTC

e12e wrote: post #33

WalterBright wrote: post #32

I always liked Ada, from my first reading around 1980 of MIL-STD-1815. Many of D's features were inspired by Ada.

If you have the time, I'd love to hear a bit about why you ended up creating D, rather than writing an Ada compiler? (Seeing how you wrote a c++ compiler...).

At the time, I had only written a couple toys. I thought writing an Ada compiler was impossible. It's also impossible to write a C++ compiler, but I didn't realize that and did it anyway (several years later, after I'd written a C compiler). I thought that C++ was just adding member functions and a few keywords to C.

Re: Introduction to Ada

#38

Post by guerby » Thu, Sep 03, 2020, 7:03 AM UTC

One thing I liked about Ada is that the authors of the language also wrote why they choose things the way they are, what was rejected, etc... Their is a document about this called "The Ada Rationale" available on the web:

http://www.ada-auth.org/standards/rationale12.html

I did contribute the HTML version of the Ada 1995 Rationale (first language revision) back in the day:

https://www.adaic.org/resources/add_content/standards/95rat/...

Re: Introduction to Ada

#39

Post by guerby » Thu, Sep 03, 2020, 7:05 AM UTC

Another thing is that the language backers made sure the ISO standard was available at no cost which was not obvious in the eighties so students could read it.

https://en.wikipedia.org/wiki/ISO/IEC_8652

I was told that the Ada guyes fought with ISO to have a per paragraph numbering to ease translations and references, ISO (at the time, don't know now) was line numbered, but they lost.

Re: Introduction to Ada

#40

Post by meej » Thu, Sep 03, 2020, 7:06 AM UTC

I got to use Ada for eight months in 1997, on a co-op at Rockwell-Collins in their General Aviation department. I learned and wrote a lot of Ada and I loved it. When I had to go back to school in the fall, I was no longer interested in writing C++ and it kind of bummed me out to have to use it again.