How to define array members in typedef?

[Kiwamu Okabe]

Dear all,

I wrote following code:

```ats
#include "share/atspre_define.hats"
#include "share/atspre_staload.hats"

#define MAXPATHLEN 1024

typedef kld_file_stat = @{ version = int, name = @[char][MAXPATHLEN]}

fun kern_kldstat {l:addr} (pf: !kld_file_stat @ l | p: ptr l): int = 0 where {
val () = !p.name.[0] := 'A'
}

implement main0 () = {
}
```

But it causes following compile error:

```
$ patscc -D_GNU_SOURCE -DATS_MEMALLOC_LIBC main.dats -lpthread
main_dats.c:122:1: warning: parameter names (without types) in
function declaration
122 | atstkind_t0ype(atstype_char) atstyarr_field(atslab__name) ;
| ^~~~~~~~~~~~~~
In file included from main_dats.c:14:
/home/kiwamu/src/ATS-Postiats/ccomp/runtime/pats_ccomp_typedefs.h:176:31:
error: field ‘atstyarr_field_undef’ declared as a function
176 | #define atstyarr_field(fname) atstyarr_field_undef(fname)
| ^~~~~~~~~~~~~~~~~~~~
main_dats.c:122:30: note: in expansion of macro ‘atstyarr_field’
122 | atstkind_t0ype(atstype_char) atstyarr_field(atslab__name) ;
| ^~~~~~~~~~~~~~
main_dats.c:127:1: warning: parameter names (without types) in
function declaration
127 | atstkind_t0ype(atstype_char) atstyarr_field(atslab__name) ;
| ^~~~~~~~~~~~~~
In file included from main_dats.c:14:
/home/kiwamu/src/ATS-Postiats/ccomp/runtime/pats_ccomp_typedefs.h:176:31:
error: field ‘atstyarr_field_undef’ declared as a function
176 | #define atstyarr_field(fname) atstyarr_field_undef(fname)
| ^~~~~~~~~~~~~~~~~~~~
main_dats.c:127:30: note: in expansion of macro ‘atstyarr_field’
127 | atstkind_t0ype(atstype_char) atstyarr_field(atslab__name) ;
| ^~~~~~~~~~~~~~
In file included from main_dats.c:15:
main_dats.c: In function ‘kern_kldstat_0’:
/home/kiwamu/src/ATS-Postiats/ccomp/runtime/pats_ccomp_instrset.h:226:45:
error: ‘postiats_tyrec_0’ has no member named ‘atslab__name’
226 | #define ATSSELfltrec(pmv, tyrec, lab) ((pmv).lab)
| ^
/home/kiwamu/src/ATS-Postiats/ccomp/runtime/pats_ccomp_instrset.h:339:34:
note: in definition of macro ‘ATSINSstore’
339 | #define ATSINSstore(pmv1, pmv2) (pmv1 = pmv2)
| ^~~~
main_dats.c:218:13: note: in expansion of macro ‘ATSSELarrptrind’
218 | ATSINSstore(ATSSELarrptrind(ATSSELfltrec(ATSderef(arg0,
postiats_tyrec_0), postiats_tyrec_1, atslab__name),
atstkind_t0ype(atstype_char), [ATSPMVi0nt(0)]), ATSPMVchar('A')) ;
| ^~~~~~~~~~~~~~~
main_dats.c:218:29: note: in expansion of macro ‘ATSSELfltrec’
218 | ATSINSstore(ATSSELarrptrind(ATSSELfltrec(ATSderef(arg0,
postiats_tyrec_0), postiats_tyrec_1, atslab__name),
atstkind_t0ype(atstype_char), [ATSPMVi0nt(0)]), ATSPMVchar('A')) ;
| ^~~~~~~~~~~~
make: *** [../../../../../../mk/ats2-fix.mk:2: all] Error 1
```

How to define array members in typedef using pure ATS language?
Or should we use the following idiom with C language?

https://github.com/githwxi/ATS-Postiats/blob/master/doc/EXAMPLE/TESTATS/fieldarr.dats#L20

Best regards,
--
Kiwamu Okabe at METASEPI DESIGN

[Dambaev Alexander]

Hi,

```

#include "share/atspre_define.hats"
#include "share/atspre_staload.hats"

#define ATS_DYNLOADFLAG 0

%{^

#define \
atstyarr_field_undef(fname) fname[]
%} // end of [%{]

#define MAXPATHLEN 1024

typedef kld_file_stat = @{ version = int, name = (@[char][MAXPATHLEN])}

fun kern_kldstat {l:addr} (pf: !kld_file_stat @ l | p: ptr l): int = 0 where {
  val () = !p.name.[0] := 'A'
}

implement main0 () = {
}

```

works, look in here: http://ats-lang.steinwaywu.com/t/error-compiling-package-in-more-recent-ats-builds/704/6

пн, 12 окт. 2020 г. в 06:17, Kiwamu Okabe <kiw...@debian.or.jp>:

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[Kiwamu Okabe]

Thanks for your kind reply.

On Tue, Oct 13, 2020 at 11:49 PM Dambaev Alexander
<ice.r...@gmail.com> wrote:
> %{^
> #define \
> atstyarr_field_undef(fname) fname[]
> %} // end of [%{]

That works for me!
But I have questions. > Hongwei

A. Why is it not supported by the official ATS compiler?
B. Will it be supported by the ATS3 compiler?

[Kiwamu Okabe]

Dear all,

On Tue, Oct 13, 2020 at 11:49 PM Dambaev Alexander
<ice.r...@gmail.com> wrote:

> %{^
> #define \
> atstyarr_field_undef(fname) fname[]
> %} // end of [%{]
>
> #define MAXPATHLEN 1024
>
> typedef kld_file_stat = @{ version = int, name = (@[char][MAXPATHLEN])}

And following more complex code is not compilable:

https://github.com/jats-ug/practice-ats/blob/master/array_typedef/main.dats

```ats
#include "share/atspre_define.hats"
#include "share/atspre_staload.hats"

%{^
#define atstyarr_field_undef(fname) fname[]
%} // end of [%{]

#define MAXPATHLEN 1024

typedef kld_file_stat = @{ version = int, name = @[char][MAXPATHLEN],
refs = int }

fun kern_kldstat {l:addr} (pf: !kld_file_stat @ l | p: ptr l): int = 0 where {
val () = !p.name.[0] := 'A'

val () = !p.refs := 1
}

implement main0 () = {
}
```

[Dambaev Alexander]

GCC says, that it wants array field at the end of the struct, so:

```

typedef kld_file_stat = @{ version = int, refs = int, name = @[char][MAXPATHLEN] }

```

works

[Kiwamu Okabe]

Thanks for your reply:

On Wed, Oct 14, 2020 at 8:50 AM Dambaev Alexander <ice.r...@gmail.com> wrote:
> GCC says, that it wants array field at the end of the struct, so:
> ```
> typedef kld_file_stat = @{ version = int, refs = int, name = @[char][MAXPATHLEN] }
> ```

Yes. But there are more complex examples such as:

https://github.com/freebsd/freebsd/blob/master/sys/sys/linker.h#L334

```c
struct kld_file_stat {
int version; /* set to sizeof(struct kld_file_stat) */
char name[MAXPATHLEN];
int refs;
int id;
caddr_t address; /* load address */
size_t size; /* size in bytes */
char pathname[MAXPATHLEN];
};
```

It should have two arrays in a typedef.

[Dambaev Alexander]

in this case the issue is that ```fname[]``` contains no size information.

This one works:
```
#define MAXPATHLEN 1024
%{^
#define MAXPATHLEN 1024
#define atstyarr_field_undef(fname) fname[MAXPATHLEN]

%} // end of [%{]

typedef kld_file_stat = @{ version = int, name = @[char][MAXPATHLEN], refs = int }
```

but I can't say how to make size not hardcoded

[Dambaev Alexander]

so in this particular case it will work, but proper fix is to dig into codegen in order to fix the generation of atstyarr_field to have a size information

[Kiwamu Okabe]

Thanks for your kind reply.

Does it mean I should apply some patch to the ATS2 compiler?
If so, I would like to wait for the initial release of ATS3 and try that.

[Dambaev Alexander]

By the way,

I decided to spend some more time on your issue and got this:

```

#include "share/atspre_define.hats"
#include "share/atspre_staload.hats"

#define ATS_DYNLOADFLAG 0

#define FIELD0_SIZE 100
#define FIELD1_SIZE 200
%{^
#define FIELD0_SIZE 100
#define FIELD1_SIZE 200

struct kld_file_stat {
  int version;
  char name[FIELD0_SIZE];
  int refs;
  char test[FIELD1_SIZE];
};

%} // end of [%{]

typedef kld_file_stat = $extype_struct"struct kld_file_stat" of
{ version = int
, name = @[char][FIELD0_SIZE]
, refs = int
, test = @[char][FIELD1_SIZE]

}

fun kern_kldstat {l:addr} (pf: !kld_file_stat @ l | p: ptr l): int = 0 where {
  val () = !p.name.[0] := 'A'
  val () = !p.refs := 1
}

implement main0 () = {
}

```

So, codegen uses kld_file_stat, defined in C. At the same time, it should be noted, that typechecker will not be able to proof, that ATS record represented as the same struct in C, so you can have:

```

{ version = int
, name = @[char][FIELD0_SIZE]
, refs = int
, test = @[char][FIELD0_SIZE]
}

```

without errors from compiler

[Kiwamu Okabe]

Dear Dambaev,

On Wed, Oct 14, 2020 at 11:49 PM Dambaev Alexander
<ice.r...@gmail.com> wrote:
> I decided to spend some more time on your issue and got this:

Thanks for sharing. It also works in my environment.
It seems like following way:

https://github.com/githwxi/ATS-Postiats/blob/master/doc/EXAMPLE/TESTATS/fieldarr.dats#L20

It also makes hints to support it on pure ATS3 codegen.