World: r4wp

I was looking to take cover just in case a battle of the wizards 
was going to happen!  Glad to hear it has been avoided.

I used to be a Dragon-Wizard level 37 in CircleMUD back when Internet 
was mainly text-only, so this could have become nasty indeed. ;-)

Is there comprehensive updated documentation for RED?

Not yet Paul. Though there is for  Red/System.

interesting new plans and strategies
  sounds good :-)

Doc: what do you mean when you say Textpad doesn't support  Unicode 
? I use Textpad 5.4.2 and see options to set UTF-8 as default text 
encoding and others options for BOM and so on.

Didier: see http://stackoverflow.com/questions/8879277/textpad-and-unicode-full-support

Huh, there are versions 6.x and 7.0 for Textpad, I've missed that, 
but the feature page is not mentioning Unicode at all: http://www.textpad.com/products/textpad/features.html

Sadly the recent (March 2013) TextPad v7 release doesn't fix this 
problem.

Got a reply from Avira, they have processed my report and the fix 
should be soon available: 

https://analysis.avira.com/en/status?uniqueid=KwPWqW429CmT1fNpbHWQgDxQ8ryDHO4T&incidentid=1412216

btw, just curious - what is it generally usefull for, to call Red 
from R/S? I can imagine it in reverse direction, but when you would 
need any such callback?

Mainly for external (from bindings) events propagation to Red level.

It will be also used in the Java and obj-c bridges.

Added new #call compilation directive to enable calling Red functions 
from Red/System.

Syntax:
    #call [<red-fun-name> <arg1> <arg2> ...]

Notes:
- it can be used only in routines body or #system body block.

- only function! value can be invoked (refinements not supported).

- arguments are either literal values or Red/System global/local 
variables.

- type casting (to a Red internal datatype) is allowed in arguments 
(avoids wasting an extra variable).

I think it is worth stressing that this is a feature of the Red compiler 
and is not available to Red/System programs compiled with the Red/System 
compiler.

So you can call Red apps from Red/System, but you can't call Red/System 
apps from Red/System, correct?

Peter: right, I've forgot to mention it.

Gregg: not sure what you mean by "Red/System app".

The #call directive invokes a Red function, it has nothing to do 
with Rebol's CALL native.

R is a compiled Red app. RS and RS2 are compiled Red/System apps. 
From RS2, I can #call into R, but not RS, correct?

No, it's not Rebol's CALL native.

Because it invokes a Red function.

Right, I understand that. I don't mean CALL, I mean #call.

There's no way you can call any function from one process to another.

#call is meant for calling Red code from Red/System in the same app.

Ah, I see my confusion. I thought this was some tricky IPC thing, 
but it's just a callback def in Red, correct?

Yes. :)

Oh, I get it now. Thanks.

Petr, in the currently available code, the GTK binding can't function 
without a callback from Red/System into Red; as Doc says, to pass 
GTK events into the Red GUI dialect engine. So far I constructed 
the callback the ugly way, but there's official support now

BTW, I've hesitated to name it #callback instead of #call.

It sounded like deep voodoo required for your bridging needs.

I guess it is still deep voodoo, just a different kind. :-)

Actually, it's fairly simple, think about a GUI app that sends a 
click event to your Red/System binding, how do you pass the event 
to Red code if you can't call it from Red/System. ;-)

Right, easy for people like me to use, but voodoo under the hood.

If you do voodoo, I can call you WitchDoc. ;-)

It replaces this:

; Call back into Red
			stack/mark-func ~on-action
			integer/push as-integer face
			integer/push action
			f_on-action
			stack/unwind
			stack/reset

For a callback with two arguments

It just pushes the Red/System arguments on a new Red stack frame 
and invokes the Red function. No black magic required. ;)

Don't tell me that. I want to imagine that it's *reeeallly* hard 
and bad things will happen if I even try to understand it. :-)

I was convinced about that for Unicode, and it didn't work out well 
;-)

Ah, one thing to not, the type casting shortcuts like: as-integer, 
as-byte, etc.. won't work within #call because the Red/System preprocessor 
is invoked too late.

not => note

That sounds important to document.

I would probably prefer it being called #callback, or some ppl might 
relate it to REBOL's  CALL :-)

Actually, it is related a bit, because in both cases, you are making 
an "external" call.

#call is more generic; you're not necessarily calling back

That's why I've opted finally for just #call.

A Red/System logic! is stored as integer!, right, not byte!?

Integer! yes.