Am 13.08.2019 um 21:00 schrieb tim Rowledge tim@rowledge.org:

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On 2019-08-13, at 11:11 AM, asarch notifications@github.com wrote:

On the contrary, thank you, thank you very much for your patience and your time. Thank you.

P.S.

Just one last issue if I may, how would you compile the image from sources?:

That's just not how it works. It *is* possible to build an image from a prescriptive definition - some folk on the Pharo list did a version last year I think, and Alejandro did a related project around '03 and I did some stuff and Craig has done a bunch of related stuff. But as a normal thing it simply doesn't mean anything. We have an image, we modify it and save it and start it, rinse and repeat. Dave Ungar pointed out many years ago that Smalltalk is saved but not born again.

Pharo since version 7.0 is bootstrapped on every build. And it is surely the best way to get a reliable artefact

Have a look at

https://github.com/pharo-project/pharo/tree/Pharo8.0/bootstrap

Norbert

tim

tim Rowledge; tim@rowledge.org; http://www.rowledge.org/tim fallacio (n): speaking logical fallacies

Hi Norbert--

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Pharo since version 7.0 is bootstrapped on every build. And it is surely the best way to get a reliable artifact.

The approach you cited uses a plethora of external tools processing source code. That's composition, but not bootstrapping (something building itself, or "pulling itself up by its own bootstraps“).

You are of course welcome to put your own definition of bootstrapping.

Heh; unsurprisingly, I assert that it's your usage that departs from the traditional meaning. :)

But why is this better?

Something building itself is better because it minimizes the cognitive load on the human attempting to understand it, by not involving so many external tools whose compositions and interactions must also be understood. It presents a more concise statement of what the system is.

For me, this makes working on the system more fun, faster, and easier to teach. I also find the resulting systems are less brittle, because there are fewer independently evolving components which can break things.

So bootstrapping should mean no operating system, no interpreter (like a shell) in between? Where is the defined border?

As much as possible, sure. In this case I'd use an operating system only as much as I needed to run a virtual machine. (Bootstrapping the virtual machine is a large area of this conversation, as yet unentered. :)

I’ve never compiled a C compiler without having an assembler and C compiler, a shell and shell scripts at hand. So I’m really interested where it is defined exactly.

I think the nature of the resulting artifact influences how relevant bootstrapping is. When building a C compiler, you probably don't care how it was that the existing C compiler you're using came to be. And developers using the built C compiler are usually much less concerned with dynamic behavior and self-reflection than Smalltalk developers are.

The example I would use is of a germinating seed. I think it's appropriate to allow special behavior earlier, leading to the existence of seeds, that is repeated less often later. We should minimize that part. Most of the work is then done by the seed operating upon itself, not by outside things operating upon it.

Pharo constructs in an image another image from nothing, then it loads some binary packages until the point it has a compiler. I’m not sure at the moment if the compiler recompiles everything again. I think you can call that bootstrapping.

I don't. That's one Pharo system composing another one, according to a plan which exists in the union of the first system and a bunch of external scripts fed to external tools. The plan is the interesting thing, and it's far from nothing.

I agree that the set of external tools should be small. By using the term „reliable“ it was regarding the artifact produced a.k.a the image. In the sense of being able to produce a bit-identical artifact you can reason about.

Right, that's what I understood you to mean.

Maybe I should have used reproducible to make it more clear.

I think reproducible composition is actually what you're discussing. One can achieve it with bootstrapping, and also with what Pharo is doing. :) The two are not synonymous, so I don't think it's a matter of being more clear, or which natural language we're using here.

Certainly reproducibility is a crucial quality; reflectivity and minimalism are as well. The object memory composition Pharo does is a very useful step, but there's more to do before achieving bootstrapping, and the specification and comprehension benefits that come with it.

-C

-- Craig Latta Black Page Digital Amsterdam :: San Francisco craig@blackpagedigital.com +31 6 2757 7177 + 1 415 287 3547