marshalling objects

marshalling objects

[Jacques Le Normand]

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hello caml list,
if I marshal an object of class c and I write the result in a file foo.txt
and, later on, I add methods to c, can I read the object in foo.txt and call
the new methods on the object?
cheers
--Jacques

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Re: [Caml-list] marshalling objects

[Basile STARYNKEVITCH]

Jacques Le Normand wrote:
> hello caml list,
> if I marshal an object of class c and I write the result in a file 
> foo.txt and, later on, I add methods to c, can I read the object in 
> foo.txt and call the new methods on the object?

First, a *.txt extension for a binary file (written thru Marshal.* 
functions) is very confusing.

Second, marshalling of any closures (including methods shared by 
objects) can only be unmarshalled by the exact same binary. So if you 
add/change code, it should not work.


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Re: [Caml-list] marshalling objects

[Richard Jones]

On Fri, Apr 25, 2008 at 04:42:02PM -0400, Jacques Le Normand wrote:
> if I marshal an object of class c and I write the result in a file foo.txt
> and, later on, I add methods to c, can I read the object in foo.txt and call
> the new methods on the object?

No.  What are you trying to accomplish?

Rich.

-- 
Richard Jones
Red Hat

marshalling objects

[Pietro Abate]

Hi all,

It's not clear to me if it is possible or not to marshall objects ? From
my tests it is not the case (output_value: abstract value (outside
heap).). Am I missing something ? What is common practice to send
objects across the wire ?

thanks,
p

--------- ex.ml

class node = object val d = 1 end ;;

let l =
    try
        let a = (new node) in
        let s = (Marshal.to_string a [])
        in print_endline "Success"; (Marshal.from_string s 0 : node)
    with Invalid_argument s -> print_endline ("Failed "^s) ; (new node)
;;

let l =
    try
        let a = (new node) in
        let s = (Marshal.to_string a [Marshal.Closures])
        in print_endline "Success"; (Marshal.from_string s 0 : node)
    with Invalid_argument s -> print_endline ("Failed "^s) ; (new node)
;;

let l =
    try
        let a = (new node) in
        let s = (Marshal.to_string a [Marshal.No_sharing])
        in print_endline "Success"; (Marshal.from_string s 0 : node)
    with Invalid_argument s -> print_endline ("Failed "^s) ; (new node)
;;

let l =
    try
        let a = (new node) in
        let s = (Marshal.to_string a [Marshal.No_sharing;Marshal.Closures])
        in print_endline "Success"; (Marshal.from_string s 0 : node)
    with Invalid_argument s -> print_endline ("Failed "^s) ; (new node)
;;


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