World: r3wp

Let me rephrase that .. you can't define an actor if that word is 
already in use

What? that is exactly what Steeve does if I understand

which actor is that?

the funtions defined in actor object aren't actually actors?

;** MISSING !!! native FOREACH has not port! as parameter

so they can't be used actors

You can use them as local functions .. just not as actors

the allowed actors are the function with port! as parameter

action!s, to be precise

and if they don't take a port, you can't use them without redefining 
their behaviour

ok i'll try to understand :-(
my scheme works used port: open rif:// ... read/seek port 1

but don't work the easy way: read rif://data/file 1, cant access 
locales

locales?

you can easily make `read/seek rif://data/file 1` work, by creating 
a custom open? actor and using that in your read actor

I use locales to stor opened files (I need two files )

Andreas any simple example of open? ?

Assuming you store port-local state in port/state, you can simply 
check port/state for not being none.

isn't it the right way? :
actor: [
		open: func [port [port!] /local path ] [
            parse port/spec/ref [thru #":" 0 2 #"/" path:]
            append port/spec compose [path: (to-file path)]
            port/locals: []
            either (0 = length? port/locals) [

                append port/locals open/seek rejoin [port/spec/path ".dat"]

                append port/locals open/seek rejoin [port/spec/path ".idx"]
                ][

                port/locals/1 open/seek rejoin [port/spec/path ".dat"]

                port/locals/2 open/seek rejoin [port/spec/path ".idx"]
            ]
        return port

you'll most likley want `port/locals: copy []`

but based on that, your open? actor would simply be: `open?: func 
[port [port!]] [not none? port/locals]`

OK I'll try it

0 = length? port/locals

can be

empty? port/locals

and in your read actor, you'll then simply do:

either open? port [{read was invoked as `open rif:// + read`}] [{read 
was invoked directly as read rif://}]

>> read/seek rif://data/file 1
** Script error: cannot access locals in path port/locals/2
** Where: Get-RIF read
** Near: Get-RIF port number

OK andreas

Maybe also a simple `if not open? port [open port]` will suffice 
in your case.

(Within the read actor.)

But typically you'll also want to add code to close the port again, 
afterwards.

can't you paste the whole code somewhere ?

This automatic open close is not clear to me after Andreas there 
is no such automation? where is the magic? :-O

There is no magic.

Rebol [
    file: %prot-rif.r
    title: "RIF protocol"
    author: "Pavel"
    rights: 'PD
    date: 13-Aug-2010
    ]

;; Local functions

Append-RIF: func [port [port!] record [binary!] ][


 write/append port/locals/2 to-binary length? head port/locals/1		;index 
 port the end of data file will be beginning of new record

 write/append port/locals/1 record							        ;data port new record 
 into data file


 return shift length? head port/locals/2 -3					        ;number of 
 records 8 bytes per record
]


Get-RIF: func [ port [port!] i [integer!] /local numentry indexpos 
recpos recend value ][


    numentry: shift length? head port/locals/2 -3                    
       ;number of records 8 bytes per record


 if any [i = 0 i > numentry] [return none]                        
    ;numbering starts at 1 ends at file end


 indexpos: multiply subtract i 1 8					                ;compute index 
 offset
	recpos: to-integer read/seek/part port/locals/2 indexpos 8

  either ( (8 * i) = length? head port/locals/2 ) [				;last record 
  special case
		recend: length? head port/locals/1
		][

  recend: to-integer read/seek/part port/locals/2 add indexpos 8 8		;internal 
  record
		]

 return read/seek/part port/locals/1 recpos subtract recend recpos
]

;; Scheme definition
make-scheme [
	name: 'rif
	title: "RIF Protocol"
	spec: make system/standard/port-spec-head []
    awake: none

	actor: [
		open: func [port [port!] /local path ] [
            parse port/spec/ref [thru #":" 0 2 #"/" path:]
            append port/spec compose [path: (to-file path)]
            port/locals: copy []
            either (0 = length? port/locals) [

                append port/locals open/seek rejoin [port/spec/path ".dat"]

                append port/locals open/seek rejoin [port/spec/path ".idx"]
                ][

                port/locals/1 open/seek rejoin [port/spec/path ".dat"]

                port/locals/2 open/seek rejoin [port/spec/path ".idx"]
            ]
        return port
        ]

        close: func [port [port!]] [
            foreach  port port/locals [close port]
        ]

        read: func [port [port!] /seek number [integer!] ] [
            Get-RIF port number
        ]

        write: func [port [port!] record [binary!]] [
            Append-RIF port record
        ]

    ]
]

arghh... not here ;-)

There are action!s in R3, which operate in port!s.

If you define custom schemes, you can implement how those actions 
behave for ports using your scheme by writing what we call "actors".

This is the elementary principle to understand.

It is elementary dear Watson :-)

Watson <- me here

http://www.rebol.net/wiki/Schemes:Notes#Actors

try to open the port at first
and then call your read function with it

when you directly use read on a path, i'm not sure that your 'open 
function is called

Ah, all documented in the wiki :)

OK lets try it better, thanks guys for lesson learned!

(Refresh, if you have the page open. I just fixed the formatting.)

But I think I'll refine the example and add an open? actor as well.

I made it 
read: func [port [port!] /seek number [integer!] ] [

		either empty? port/locals [
		open port
            	return Get-RIF port number
		][
		return Get-RIF port number
		]

and it works now

Btw Pavel, in my virtual-block scheme, the reason why I rebound the 
actors, is that I don't like to use nasty long path to acces my locals.

I hope close is in garbage collector as mentioned in wiki

And second is more speed?

It should be :-)

can't you 

return get-rif either empty? ...