[rebootthesystem]

You see, i am arguing from practice and you from theory. In theory you are absolutely correct. In practice the vast majority of code is NOT written in total languages. A more likely scenario is one where somebody is using language X and, in the middle of a project they decide there's this recursion thing they read about or learned in school. And off they go. In that context. In the context of a practical world where virtually nobody is is using total languages, the injection of recursion by the wrong people is dangerous. I say this from first hand experience.

Let's just agree to disagree.

[sklogic]

> You see, i am arguing from practice and you from theory.

???

My "theory" is being extremely widely used in practice. Take a look at the Intel FDIV bug history and its consequences for example. They've been formally certifying critical parts of the hardware ever since then.

Or take a look at the widely used seL4 kernel: http://ssrg.nicta.com.au/projects/seL4/

> In practice the vast majority of code is NOT written in total languages.

And this is the problem, not recursion or whatever else. Incompetent coders are evil, and you cannot blame any particular technique for any failures. Luckily, in my practice, nobody ever dared to let any graduate larvae to hang anywhere near any kind of mission-critial code. I've heard stories, of course, but never witnessed anything like that myself.

> they decide there's this recursion thing they read about or learned in school.

As I said, people of this degree of cognitive development will screw up anyway, no matter what techniques they use. In a monkey with a hand grenade situation you should not worry too much about a sharp stick this monkey may accidentally pick up.

> the injection of recursion by the wrong people is dangerous

Pretty much everything else they do is equally or more dangerous anyway.

And, getting back to your rant which started this thread - you said that recursion is dangerous and useless. Unconditionally.

Now it turns out that it may be dangerous, but only when used by complete tools and only in heavily mission-critical embedded projects. Quite a distance from what you've said originally. No wonder you've got such a response.

[rebootthesystem]

I think you are at a point where you just want to argue to argue because. I'll give one more spin and I am out.

The world you paint isn't the real world. The world I am considering is this one:

http://langpop.com/

In other words, one where your total languages are virtually nowhere to be found. Not by a small margin, by a landslide.

So, as they say in the movies, in a world where the top 5 most used languages are C and and C derivatives and total languages are almost nowhere to be found or a thing of academia, then, yes, what I am saying is very relevant and, dare I say, true and appropriate.

And, BTW, even experienced programmers screw up recursion because it just isn't used that often. I don't want to blame newbies.

So I look at this world, as evidenced by the charts on that site and a data I am sure could be dug up on a bunch of other sites I can very easily conclude that total languages are still mostly in academia and so is safe recursion. In a world dominated by C and derivatives, recursion can be really dangerous. Bad recursion hidden inside a library can be really bad news.

Anyhow, I am done with the back and forth. I understand where you want to come from. I am just asking that you understand that the frame of reference you have constructed is not one that matches our current reality. Which means one can't say that recursion is safe because when total languages when virtually nobody, in relative terms, uses them. And then, when they do use them, you have to ask what they are using them for. Is it Academia or real world application?

Enough said. Thanks for a good discussion. I wish people were not so nasty with down-votes on HN as it detracts from trying to have a discussion based on ideas contrary to the underlying HN culture. That's just the way it is.

[sklogic]

> The world you paint isn't the real world.

My world is this one:

http://www.prover.com/company/press/view/?id=47

http://www.cl.cam.ac.uk/~jrh13/slides/nasa-14apr10/slides.pd...

http://sel4.systems/

... and so on.

And, honestly, I don't want to have anything in common with your "real world", where graduate larvae with IQ < 80 is allowed to code automotive microcontrollers.

> In other words, one where your total languages are virtually nowhere to be found.

We're speaking about mission critical stuff, which is already a virtually nonexistent thing dwarfed by CRUD and all such crap.

> And, BTW, even experienced programmers screw up recursion because it just isn't used that often. I don't want to blame newbies.

I see. You did not get a single word from what I said. Pity.

Let me repeat my point again: humans are brainless scumbags. They should never be trusted with anything important. If anything can be screwed up, it will be screwed up in an epic scale. The only way to avoid an epic screwup is to exclude this brainless scum from the process, and let the immaculate formal systems do the job.

> I am just asking that you understand that the frame of reference you have constructed is not one that matches our current reality.

I'd prefer to stay away as far as possible from your reality. Mine is much better. In my reality, a code without multiple layers of formal proof would not ever be signed off for anything mission critical (although I admit that the most deadly stuff I worked with were anti-aircraft systems, nothing fancy like nuclear plants and such).