World: r3wp

So if, for example, DECODE-CGI is in an "optionally included" (which 
I guess == "delay-loaded") CGI module, DECODE-CGI will be available 
even if you don't import 'cgi first?

A regular, non-delayed module could include a delayed module that 
does the real work. And there are other tricks that can be done.

Well, I personally see not cluttering the "global" namespace with 
those names as a great advantage.

A lot of those names won't need to be exported at all. Internal use 
words can stay internal.

The wiki link above has some other ideas for advanced tricks, though 
that page is still being written.

And it's not user-level, so be warned: Here there be dragons :)

OK, the third rewrite of the module system has a few simplifications 
as related to the (unreleased) second rewrite, but it is mostly the 
same design. I will be revising the wiki above with the changes.

Now that issues are no long strings but words, maybe we want to revisit 
the decision to introduce EXPORT and HIDDEN keywords. In http://www.rebol.net/r3blogs/0300.html
the main reason not to use #export and #hidden seems to be the nature 
of issues.

I'd actually prefer to use #export and #hidden, as I rather dislike 
the concept of "module keywords".

I think that most of guys did not accept changes to issue dtype ... 
maybe it should be put back to original functionality, no?

That is a separate discussion.

Currently we have the issues-as-words, and it does not look like 
they are going away, but rather their semantics be adapted to address 
the concerns raised.

*VERY* good catch !!!

pekr, most of whined and tried to put the change in our perspective, 
yes  :-)

Pekr be happy i absolutly don't care about any issue ;) aaaaaaaaaahahahaha

so much of a thing used by 3 guys around the world. That impress 
me.

Well, I hope that we are able to make things good enough for you 
without your help. Wish us luck!

hum that was the cas before too no? You will need luck that's a sure 
thing.

It wasn't a request for assistance. If you want to help, it will 
be welcomed. If not, we are doing well now. Either way you are free 
to use what we create, or not. Enjoy!

Over the last day I have been fleshing out the test suite for the 
new module system. Almost all features have corresponding tests now. 
As soon as we have complete coverage I will try to get the tests 
published somewhere official. FYI, alpha 109 fails a lot of the tests, 
but also in the last day I fixed all of the errors that were causing 
test failures. In theory - I need a new build with the fixes to be 
sure, but code tracing says the behavior matches the tests. In any 
case, the test suite will have full feature coverage before alpha 
110 comes out.

I have also started writing some simple charts to explain the details 
of the design and behavior of the module system. In CSV format. These 
charts helped a lot in the fixing of the problems and implementation 
of the tests. As with the tests, I will try to get the charts published 
somewhere official.

With alpha 109 we got some significant usability revisions to the 
design of the module system, relative to alpha 108:

- The return of unnamed modules. They are now changed to private 
modules (mixins) which aren't stored in the system modules list.

- IMPORT now effectively works a lot like the Needs header in user 
scripts. Most users won't be able to tell the difference.

- The return value of IMPORT block is now a block of the modules 
you imported (but not the modules *they* imported).

- The refinements of IMPORT have been renamed and their behavior 
tweaked to be nicer and more useful - the first API change since 
Carl's original.
  - /no-share: The previous /isolate option. Same behavior.

  - /no-lib: Don't export to the runtime library. Private modules don't 
  do this anyways. Also, don't add to the system modules list.

  - /no-user: Don't export to the user context, even as a private module. 
  When importing to a module, /no-user applies.

- The old /only option was split into /no-lib and /no-user, for more 
control. Specify both if you don't want IMPORT to export anything.

Alpha 110 should bring these changes:

- The above will work properly. With a bunch of specs and charts 
that define what "properly" means. With a full test suite to make 
sure.

For the sake of completeness, here are the highlights of the alpha 
108 changes:

- Script headers can have an options block, a simple block of flag 
words. User extensible.

- The standard script header now has a lot fewer words in it. More 
stuff is optional or in the options block.

- Script compression, either binary and base 64 binary! encoded. 
Automatic, transparent.

- Script checksums, both to verify the script and for IMPORT to compare 
with. Applies to decompressed source.

- An optional script length header field (like http's Content-Length). 
This allows binary script embedding.

- Internal support for getting the end of an embedded script, so 
a multi-loader is possible.

- The 'content and 'isolate header fields are changed to option words. 
The content is still saved to a 'content header field.

- The 'content field, if set, is set to the start position of the 
script proper, even if there is stuff before it.

- The whole system/contexts/system concept is gone, as part of the 
system restructuring. Now we have SYS.

- The system/contexts/exports concept is gone too, replaced by a 
not-module-specific runtime library called LIB.

- The old type: 'extension is now the 'extension header option word. 
The only module type is 'module. And it's optional for most code.

- Mixins are now called "private modules", and are flagged by the 
'private option word. And they can have names.

- Private modules can be added to the system modules list (because 
of the names). This lets them be reused without being reloaded.

- Unnamed modules are now prohibited (until alpha 109, where they 
become private modules that reload every time).

- Delayed modules, which can be partially loaded and then not fully 
made until they are imported. Use the 'delay option word.

- A HIDDEN module source keyword, which applies PROTECT/hide to a 
word or words. Acts like the EXPORT keyword.

- Better errors are triggered when the bad things happen. Including 
new error codes.

- DO and MAKE--MODULE intrinsics are now in sys, as DO* and MAKE-MODULE*. 
No more system/intrinsics.

- DO-NEEDS is no longer exported (it's in sys). IMPORT block is a 
public alias for DO-NEEDS anyways.

- MODULE now makes modules that act more like those in script files. 
And has /mixin support too.

- A whole bunch of changes and fixes to native functions to support 
the above stuff.

Shadwolf's "used by 3 guys around the world" comment brings to mind 
one of the more ironic things about the module system:


Most user code for R3 will be written in "scripts", not "modules". 
This will be even more the case once we get more of concurrency working, 
because "script" code works in the user context, which will be task-local. 
We are going out of our way to make it extremely easy to just use 
"scripts" and not have to bother with "modules".


The ironic part is that "scripts" are just another kind of module, 
one of the three including regular and isolated modules. In particular, 
user scripts are a kind of module that we try to make as non-module-like 
as it is possible to be (given that they run in a module system). 
The entire module system structure is built around the challenge 
of making the module system apparently disappear, or at least be 
something that you can be almost completely ignorant of. The module 
system is built for script programmers, to let people do PITS on 
a systerm that they don't even have to know is capable of the most 
advanced PITL.


So the module system we are discussing here will be used by *everyone 
who programs in R3*, whether they know it or not :)

(I am politely assuming that Shadwolf was not referring to the entire 
REBOL community when he said "3 guys".)

can modules be released as encrypted code ?

Not much point I guess

Not yet, but that is planned. It's even mentioned in the design wiki.

are modules signed?

Cryptographic signing is also planned, as also mentioned in the wiki. 
Both will work in a similar way to the compression and checksum, 
respectively.

sha256 ?

We plan to do encryption and signing. We aren't far enough along 
in the plan to know how we will do these.

The checksum is CHECKSUM/secure, whatever algorithm that is.

Checksum/secure is SHA-1

In theory, you could generate R3 scripts using R2 and still have 
most of the same features. Loading them would be trickier though.

SAVE is pretty straightforward and doesn't use any R3-specific features.

Is the cryptography being rehashed from R2 ?

Rehashed :) No, we're using the old hashes :)

It would be good if certificate use could be more easily enabled

I can't say if that will be the case with the encryption or signing 
though.

Certificate use is something R3 doesn't do well yet, afaik (which 
isn't far). We will likely have to do a lot of infrastructure work 
before we can do encryption or signing.

Nonetheless, this is something we want (need?) to do, so the crypto 
infrastructure work will need to be done.

I forgot to mention the LOAD and SAVE option changes in alpha 108. 
Perhaps later after I sleep, if their HELP is insufficient.

Most user code for R3 will be written in 'scripts', not 'modules'.

Lets hope that this prediction will turn out to be wrong.

Thanks for the summary, Brian.

Need to find some time to play with it first, but it sounds like 
"private" modules and/or IMPORT/no-lib/no-user will be most useful.

The charts will help. I didn't have a problem with /isolate and /only 
as names. The new ones sound rather clunky at first glance, but I 
may grow to like them. Most important, I think, are small examples 
demonstrating why we have the various options. I hope the charts 
are the first step on that path.

Thanks Brian!

The new option names are a good choice because all of the /no-* options 
are a way of breaking modules that otherwise depend on acting the 
way that they were written. The whole group of them needs a warning 
label.

Andreas, for library code you are correct, but most end-developers 
just use library code, they don't write so much of it.

My hope is that eventually R3 will be used for more than just small 
and dirty throw-away scripts. And that'll directly induce the need 
for a module system.

My hope is to never, ever come across a "do %..." that "loads" utility 
functions again (in R3).