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digitalmars.D.learn - unserialize variants

reply "gedaiu" <szabobogdan yahoo.com> writes:
Hi,

i want to save data from an array of variants into a file. I saw 
that to!string format the array content in a nice way... There is 
a way of converting the resulted string back to an array of 
varianta?

thanks,
Bogdan
Aug 31 2013
parent reply =?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:
On 08/31/2013 10:22 PM, gedaiu wrote:> Hi,

 i want to save data from an array of variants into a file. I saw that
 to!string format the array content in a nice way...


I don't think the format is sufficient for recreating the array:

import std.variant;
import std.conv;
import std.stdio;

struct S
{
     int i;
}

void main()
{
     auto a = [ Variant(42), Variant("hello"), Variant(S(5)) ];
     writeln(a);
}

Outputs:

[42, hello, S(5)]

We can only guess that 'hello' is a string but what if it were the 
string "43"? It would look like an int. Also, any type can overload 
toString; so, S(5) could output itself as e.g. "world".


 There is a way of
 converting the resulted string back to an array of varianta?


This requires a serialization module. std.serialization is in review 
right now:

   http://forum.dlang.org/post/hsnmxykmoytfvwroikzk forum.dlang.org

Its author Jacob Carlborg already has a serialization module called Orange:

   https://github.com/jacob-carlborg/orange


 thanks,
 Bogdan


Ali
Sep 01 2013
parent "gedaiu" <szabobogdan yahoo.com> writes:
Thanks for the response... I thought there is a faster way for 
that. I will use the standard lib or i will use json to store 
that into a file.


Thanks,
Bogdan




On Sunday, 1 September 2013 at 16:19:32 UTC, Ali Çehreli wrote:

 On 08/31/2013 10:22 PM, gedaiu wrote:> Hi,

 i want to save data from an array of variants into a file. I


 saw that

 to!string format the array content in a nice way...


 I don't think the format is sufficient for recreating the array:

 import std.variant;
 import std.conv;
 import std.stdio;

 struct S
 {
     int i;
 }

 void main()
 {
     auto a = [ Variant(42), Variant("hello"), Variant(S(5)) ];
     writeln(a);
 }

 Outputs:

 [42, hello, S(5)]

 We can only guess that 'hello' is a string but what if it were 
 the string "43"? It would look like an int. Also, any type can 
 overload toString; so, S(5) could output itself as e.g. "world".


 There is a way of
 converting the resulted string back to an array of varianta?


 This requires a serialization module. std.serialization is in 
 review right now:

   
 http://forum.dlang.org/post/hsnmxykmoytfvwroikzk forum.dlang.org

 Its author Jacob Carlborg already has a serialization module 
 called Orange:

   https://github.com/jacob-carlborg/orange


 thanks,
 Bogdan


 Ali
Sep 02 2013