FFI | How to declare pointer to external structure in #fields?

Am 18.05.2020 20:00:16 schrieb Vanessa Freudenberg <[hidden email]>:

On Mon, May 18, 2020 at 7:05 AM Marcel Taeumel <[hidden email]> wrote:

Hi, there!

In the #fields method of a new ExternalStructure, how can I express a pointer to another external structure?

First, non-pointer works as expected:

^ #( (other MyStruct) )

Second, this just treats it as a void*, which returns a generic ExternalData:

^ #( (other 'MyStruct*') )

Third, this gives me a debugger:

^ #( (other MyStruct *) )

I don't have the code in front of me but there is the parser you could check ;)

It might be *MyStruct.

 - Vanessa - 

Am 18.05.2020 23:47:38 schrieb Vanessa Freudenberg <[hidden email]>:

On Mon, May 18, 2020 at 12:56 PM Nicolas Cellier <[hidden email]> wrote:

Hi all,

I started to write a documentation of FFI implementation two or three months ago, I don't remember exactly, it's an eternity. The lock down did not give me an opportunity to continue. I want to publish with some liberal CC license, but I don't have chosen a support format yet. On one side, I wanted to focus on contents more than on the format. But on the other side, I want some graphical illustrations accurate enough. I wrote in Word because it was easy for me to include tables and graphics, but it's kinda stupid, especially because Word make you focus on format more than contents ! LaTeX is not general enough, it would rather be a backend nowadays. I contemplated using pandoc which has good support, or the much more limited Pilar, which at least is Smalltalk based...

The structure is not well established and the work is very preliminary, but since there is some demand, I give a pdf copy here as is, I hope it's not too big for the list. This probably should better be continued as a collaborative work anyway.

Awesome!

- Vanessa - 

Am 18.05.2020 21:28:49 schrieb Levente Uzonyi <[hidden email]>:

Hi Marcel,

On Mon, 18 May 2020, Marcel Taeumel wrote:

> Hi, there!
>
> In the #fields method of a new ExternalStructure, how can I express a pointer to another external structure?
>
> First, non-pointer works as expected:
> ^ #( (other MyStruct) )
>
> Second, this just treats it as a void*, which returns a generic ExternalData:
> ^ #( (other 'MyStruct*') )

This is how it should be written. Does MyStruct exist when you're writing
this method? If yes, is there a refence to that class in ExternalType's
StructTypes class variable?

Levente

>
> Third, this gives me a debugger:
> ^ #( (other MyStruct *) )
>
> :-)
>
> Best,
> Marcel
>
>

Am 19.05.2020 09:30:23 schrieb Nicolas Cellier <[hidden email]>:

Le mar. 19 mai 2020 à 08:15, Marcel Taeumel <[hidden email]> a écrit :

> How does UFFI come here?

I just wanted to backtrack those struct pointers lead to the accessor in Pharo. But it gave me no easy clue that I could apply to plain FFI in Squeak. :-)

> I started to write a documentation of FFI implementation two or three months ago ...

Yeah! I will have a look at it. GitHub Markdown + embedded graphics also hosted on GitHub could work. And support pull requests. :-) Maybe put it into the osvm repository.

Hi Marcel,

this was my exact intention, but I wanted some more powerful Markdown, so considering either pandoc or pilar...

Best,

Marcel

Am 18.05.2020 23:47:38 schrieb Vanessa Freudenberg <[hidden email]>:

On Mon, May 18, 2020 at 12:56 PM Nicolas Cellier <[hidden email]> wrote:

Hi all,

I started to write a documentation of FFI implementation two or three months ago, I don't remember exactly, it's an eternity. The lock down did not give me an opportunity to continue. I want to publish with some liberal CC license, but I don't have chosen a support format yet. On one side, I wanted to focus on contents more than on the format. But on the other side, I want some graphical illustrations accurate enough. I wrote in Word because it was easy for me to include tables and graphics, but it's kinda stupid, especially because Word make you focus on format more than contents ! LaTeX is not general enough, it would rather be a backend nowadays. I contemplated using pandoc which has good support, or the much more limited Pilar, which at least is Smalltalk based...

The structure is not well established and the work is very preliminary, but since there is some demand, I give a pdf copy here as is, I hope it's not too big for the list. This probably should better be continued as a collaborative work anyway.

Awesome!

- Vanessa - 

Am 19.05.2020 09:52:57 schrieb Tobias Pape <[hidden email]>:

> On 19.05.2020, at 08:46, Marcel Taeumel wrote:
>
> Hi Levente.
>
> > Does MyStruct exist when you're writing this method?
>
> Yes.
>
> > If yes, is there a refence to that class in ExternalType's StructTypes class variable?
>
> Yes.
>
> **
>
> The issue was that I wanted to make a pointer to the struct I am currently (re-)defining:
>

> struct MyStruct {
> MyStruct *foobar;
> };

If you have control over the source, try this:

typedef struct s_MyStruct MyStruct;
typedef MyStruct* pMyStruct;
struct s_MyStruct {
pMyStruct *foobar;
};

-t


>
> Works fine when pointing to other structs. Should code generation work for this case? :-)
>
> Best,
> Marcel
>> Am 18.05.2020 21:28:49 schrieb Levente Uzonyi :
>>
>> Hi Marcel,
>>
>> On Mon, 18 May 2020, Marcel Taeumel wrote:
>>
>> > Hi, there!
>> >
>> > In the #fields method of a new ExternalStructure, how can I express a pointer to another external structure?
>> >
>> > First, non-pointer works as expected:
>> > ^ #( (other MyStruct) )
>> >
>> > Second, this just treats it as a void*, which returns a generic ExternalData:
>> > ^ #( (other 'MyStruct*') )
>>
>> This is how it should be written. Does MyStruct exist when you're writing
>> this method? If yes, is there a refence to that class in ExternalType's
>> StructTypes class variable?
>>
>> Levente
>>
>> >
>> > Third, this gives me a debugger:
>> > ^ #( (other MyStruct *) )
>> >
>> > :-)
>> >
>> > Best,
>> > Marcel
>> >
>> >
>>
>