World: r3wp

The past few weeks I've had more time to devote to Rebol.  I'm working 
on some typical examples and routines to get aquainted with it.  
So I appreciate all the help I'm getting from this forum.  Currently 
just playing with the delete-dir function.

I'm not able to get this to work....is this even possible.....

in the environment: myPath = C:\myTemp

	myPath: probe get-env "myTemp"

 ....(tried several iterations of code here to fix the path perfectly)
	delete-dir myTemp

also tried reduce 

the path has been refomed to //%/myTemp/, %C/myTemp/,  and several 
others forms.

it says that it expects a dir argument of type: file url

>> exists? %c/windows
== false
>> exists? %/c/windows
== true

note two slashes in second examples surrounding /C/

also, you can use handy functions as to-rebol-file, to-local-file, 
to convert to/from local/rebol file/path formats ...

also - if you want to use C:\myTemp, better use "C:\myTemp", rebol 
thinks it is an URL type ...

>> to-rebol-file "C:\mypath"
== %/C/mypath
>> to-rebol-file C:\mypath

** Script Error: to-rebol-file expected path argument of type: file 
string
** Near: to-rebol-file C:\mypath

HTH :-)

Yes this helped thank you.

I'll look some more later, but what seemed to fix it was the built 
in function 'to-rebol file'  :-)

can I ask if you know any other options for rebol to talk to other 
independant processes on linux? For example could I use something 
like named pipes?

There was a script for Rebol->Arexx once called Pipebridge.  Wonder 
if it's applicable to Linux?

Rebol<->Arexx

Janko; I'm pretty sure a mkfifo named pipe will work; BUT as usual, 
either end borks, the other end hangs.

Chris: I googled about what you said but didn't find any source, 
but interesting.. this stuff was running on amiga at the time :)

btiffin: I am newbie at linux... you mean I can make a named pipe 
in command line with mkfifo and then rebol uses that as a normal 
filename to write/read from it? Similarly the other language has 
Unix package and can make named pipes by it's own... can rebol create 
pipe too? (sorry if I got it all wrong)

about hanging, yes I read that write does not happen untill there 
is a read at the other side and vice versa so I was thinking if there 
is some king of timeout possible..

hm.. but why is it then called fifo if read needs to happen at the 
same time as write, I thought it's some sort of fifo (first in first 
out) stack/queue

Well normally fifo files are created in blocking mode, so yeah a 
write won't complete until a read occurs and a read will wait for 
a writer (by default).  I'll be honest, I've not done this from REBOL, 
but with 2.7.6 and LOAD/LIBRARY freed, we can do any libc6 calls 
that we want, so you should be able to set a non blocking mode and 
get true multiple writes and reads that will return empty if no data 
is queued.


For OpenCOBOL I implemented POSIX Message Queues; as MQ_NOTIFY will 
make a callback when the queue goes from empty to non-empty and you 
don't have to worry about spinning on a read.


If you don't mind playing with  make routine!  take a look at mq_open 
and friends (man mq_overview) it might offer more control for IPC.

thanks btiffin for such great explanation, yes I was looking at message 
queues too at first but then someone proposed pipes and they do seem 
more accessible/simple to start in a way.

Is there any article or blog post about 2.7.6 being able to load 
native libraries? I searched and couldn't find any info on this.. 
I found docs for REBOL/Command/SDK version so this would be a place 
to start experimenting probably

Janko; yep.  It's weird, docs wise, but  make routine!  is a new 
bonus layer that hasn't made it's way to the main documentation. 
 Our good Gregg is a goto guy when it comes to knowing some of the 
foibles invovled.  If you like learning by example http://www.rebol.org/cgi-bin/cgiwrap/rebol/view-script.r?script=capture-screen.r
or http://www.rebol.org/cgi-bin/cgiwrap/rebol/view-script.r?script=capture-screen.r
  There are other examples.

great, I love learning by example :) .. btw .. both of your links 
are the same I think

Sorry Janko;  the second was supposed to be http://www.rebol.org/view-script.r?script=sqlite3-protocol.r
  that's what I get for not reading what I'm writing.

oh, great just what I need... I was fixing/modding a sqlite binding 
in factor already

so I can compare a little , and I will probably need it also

>> a: copy []
== []
>> b: 'test
== test
>> append a :b
== [test]
>> type? first a
== word!
>> find a 'test
== [test]
>> c: ['test]
== ['test]
>> find a first c
== none

That just bothers me.

type? first ['test]
== lit-word!

Yes I know.

My point is that REBOL is not consistent.

Why can I do a find using a lit-word but not get results when using 
the lit word from a block?

find a 'test works but find a first c doesnt.

I would have to use find a to-word first c to get a match.

I think it is a bug. But we will probably see gurus trying to find 
an excuse, why sometimes you can't code in REBOL different way than 
to simply try some stuff in console ...

And - imo if RT would post some formal specification to the language, 
we could fix some gotchas and surprises, not trying to find academic 
theories, why it work certain way ...

insert as an operation does not preserve datatype. It reduces litword 
to word. Not sure there is a reason to do so ...

Yeah, that to me would be a bug.

>> append [] to-lit-word 'a
== ['a]

Yeah Henrik but that is a workaround really.

the 'a was already a lit-word to begin with.

Henrik - but - that is exactly the excuse I was talking about

why should I use to-whatever for one datatype, but not for the other 
one?

the question is probably which operation is more common.

I'd bet Carl did it that way, because it is something he does more, 
than the other way around.

hmm, but it can really lead to surprises, as Paul got - trying to 
find something by reference ....

To me it is one of the exceptions to the rule things.  With REBOL 
you gotta have all these exceptions to the rule.

I'm not defending it, just trying to come up with a theory.

... but yes, REBOL is dynamic, so it might be a problem, to have 
all cases working as expected ...

lol

because I know that Carl works alot more with cases of usage rather 
than theoretical correctness, as long as the result isn't completely 
backwards/illogical.