World: r3wp

Not sure the best forum to put this on (to where Carl will see it). 
Are there plans in the future for actual bit operations besides and/or/xor? 
RIght now, bit shifting, rotating, etc. are extremely painful (and 
slow compared to what they should be) to do.

rebcode supports shifting; not sure if it makes sense to have a native 
too, maybe yes.

shifting is a very basic operation. I don't understand how it couldn't 
be part of the core, native functions. The same could be said of 
AND and OR, and just make them logical operators instead of bitwise.

well, shifting is very lowlevel, and there are not many use cases 
outside of rebcode.

I disagree, but that's fine. I imagine the majority of those using 
REBOL are using it for non-low level things. I just don't happen 
to be one of them. REBOL is a great language for making domain specific 
languages, and many DSLs would benefit from a little more low-level 
control.

I have to disagree as well. I've bumped into a few examples where 
bit-operations would be very nice to have, if you want to use REBOL 
for prototyping bit-operations in another environment. Afterall we 
can create bitsets, why not allow full manipulation of them?

Well, you can write your own; if just prototyping, the speed isn't 
critical (we did 160 bit math for Maarten, using bitsets, at one 
point). That said, if you can use a version with rebcode, just wrap 
a mezzanine around the ops. 


That said, I wouldn't mind having standard SHIFT and ROTATE funcs 
that can operate on integer, or series values. Bit ops are also necessary 
for implementing certain algorithms.

Here are prototype funcs for SHIFT and ROTATE (plus a couple supporting 
funcs). Is it worth some time to come up with good ones and submit 
them for inclusion in R3?

; used in SHIFT below
    dup: func [value len [integer!] /local type] [

        type: either series? value [value] [either char? value [""] [[]]]
		head insert/only/dup make type len value len
    ]

    ; used in SHIFT below
    make-blank-value: func [type] [
        any [
            attempt [make type 0]
            attempt [make type ""]
            attempt [make type []]
            attempt [make type none]
        ]
    ]


    ; The new PAD/JUSTIFY func might be used to implement this as well.
    shift: func [
        "Shift values in a series; length doesn't change."
        series [series!]
        /left   "Shift left (the default)"
        /right  "Shift right"

        /part range [number!] "Shift this many positions"  ; TBD series! 
        support?
        /with fill "Fill vacated slots with this value"
        /local pad
    ][
        range: any [range 1]
        if any [empty? series  0 = range] [return series]
        pad: dup any [fill  make-blank-value last series] range
        either right [

            head insert head clear skip tail series negate range pad
        ][
            append remove/part series range pad
        ]
    ]

    rotate: func [
        "Rotate values in a series."
        series [series!]
        /left   "Rotate left (the default)"
        /right  "Rotate right"

        /part range [number!] "Rotate this many positions"  ; TBD series! 
        support?
        /local offset pad
    ][
        range: any [all [range  range // length? series] 1]
        if any [empty? series  zero? range] [return series]
        either right [
            offset: does [skip tail series negate range]
            pad: copy offset
            head insert head clear offset pad
        ][
            pad: copy/part series range
            append remove/part series range pad
        ]
    ]

I am trying right now to write a file to an FTP server. What I would 
like to do is:
- open the port 
- try to write the file
- if that fails, create the parent directory if necessary
- try to write the file again
- close the port

The difficult part is keeping the port open.

... and I have my head deep in FTP handler... :)

Ah... figured out how to do that :) The solution is to disable close-on-fail 
in the handler, so that a failure in open does not close the ports. 
This allows the command port to be reused for other commands, such 
as make-dir.

Now to make it nice...

Anyone know how to write to the parallel port ?

I don't know if this will help: http://www.rebol.org/cgi-bin/cgiwrap/rebol/ml-display-thread.r?m=rmlGBVQ

Gregg says write %//prn .. I'll give that a go.

With image/rgb I can get all the RGB (24-bit) data. With /alpha I 
can get all the (8-bit) alpha data. Is there one to get RGBA (or 
ARGB) so the alpha data is interleaved with the RGB data (32-bit)?

Try to-binary logo.gif

So simple -- like most things with REBOL. Don't know why I didn't 
try that. Thanks.

Not everything is simple - yet...

Like bit shifting. I do appreciate Gregg's functions. However, when 
something that boils down to a single instruction in hardware requires 
6 lines of code and multiple function calls, something is wrong. 
;)

indeed why bit shifting is needed, at least as built in mezzanine 
functions

Hmm.  Does 'send have a forward option?

ie. forward an existing email?

how to bind this correctly ?

>> b: { (blue)}
== " (blue)"
>> compose to-block  b
** Script Error: blue word has no context
** Where: halt-view
** Near: blue

Oh, 'to-block does still not bind? good to know. Use 'load .

Can't use 'load as other stuff in the block.

will cause errors.

Ye must bind to an example worde, as it is written in the olde texte.

need to get this working for my postscript dialect to be able to 
use rebol colours

instead of tuples

Can you use REDUCE/ONLY?

let me try.

same problem

this is what I want to do

{ font (red) } => [ font 255.0.0 ]

It may be that I have to include the colour words in my parser.

Do you mean like this?

>> b: "(blue)"
== "(blue)"
>> compose bind to block! b 'white
== [0.0.255]


You just have to give any word from the same context to bind ... 
so inthis case any word from the global context (i.e. system/words).

The only point to be aware of: If all this happens in a different 
context, and you happen to have a word named 'white in this context, 
then you have to use another word.

hey thanks Ingo!

Anyone written a fetchmail in Rebol?

does send have a forward option
 - maybe you are looking at RESEND

at = for

ahh.. a new function :)

this is probably outside of core and more at the OS level, but it 
would be nice to somehow check if a script is already running via 
LAUNCH, to make sure it's only launched one instance at a time. Is 
this possible?

maybe try to launch a dummy script and catch the error.

another thing could be to have a masterscript running and let the 
other scripts report to it via LNS, but that's not very elegant...

You could use a semaphore of some kind (port/file).

- the original script will be able to launch the dummy script and 
thus no error

- the launched script will not be able to launch the dummy script 
and thus an error