possible fun template misunderstanding

[xor.r...@gmail.com]

lately, i got interested in ats2. i wrote some trivia code and stumbled upon the following:

i would say

- [bp1.dats] output is wrong?

- [bp2.dats] should not compile, but does?

- [bp3.dats] is correct (this was my "fix" for bp1.dats)?

is it because of the actual template params not beeing used?? is this wanted behaviour or a bug?

especially bp2.dats looks extremely suspicous.

bp1.dats:


// patscc -DATS_MEMALLOC_LIBC -Ofast -flto -o bp bp.dats


#include "share/atspre_staload.hats"


staload UN = "prelude/SATS/unsafe.sats"


absvt@ype be = ptr
absvt@ype le = ptr


typedef u16 = uint16


extern fun{env:vt0p} rd16 ( env: &env >> _ ) : u16


implmnt{be} rd16 ( env ) = $UN.cast{u16}(23)
implmnt{le} rd16 ( env ) = $UN.cast{u16}(42)


assume be = @{a=int}
assume le = @{b=int}


implmnt main0 ( argc, argv ) : void =
    let val odd = argc % 2 = 0
        var env_be: be = @{a=0}
        var env_le: le = @{b=0}
    in
        if odd
            then (
                print!("be: ")
              ; println!(rd16(env_be))
            )
        else (
            print!("le: ")
          ; println!(rd16(env_le))
        )
    end
$ patscc -DATS_MEMALLOC_LIBC -Ofast -flto -o bp1 bp1.dats
$ ./bp1 x
be: 42
$ ./bp1 x y
le: 42

bp2.dats:


// patscc -DATS_MEMALLOC_LIBC -Ofast -flto -o bp bp.dats


#include "share/atspre_staload.hats"


staload UN = "prelude/SATS/unsafe.sats"


absvt@ype be = ptr
absvt@ype le = ptr


typedef u16 = uint16


extern fun{env:vt0p} rd16 ( env: &env >> _ ) : u16


assume be = @{a=int}
assume le = @{b=int}


implmnt main0 ( argc, argv ) : void =
    let val odd = argc % 2 = 0
        var env_be: be = @{a=0}
        var env_le: le = @{b=0}
    in
        if odd
            then let implmnt{be} rd16 ( env ) = $UN.cast{u16}(23) in (
                print!("be: ")
              ; println!(rd16(env_be))
            ) end
        else let implmnt{be} rd16 ( env ) = $UN.cast{u16}(42) in (
            print!("le: ")
          ; println!(rd16(env_le))
        ) end
    end
$ patscc -DATS_MEMALLOC_LIBC -Ofast -flto -o bp2 bp2.dats
$ ./bp2 x
be: 23
$ ./bp2 x y
le: 42

bp3.dats


// patscc -DATS_MEMALLOC_LIBC -Ofast -flto -o bp bp.dats


#include "share/atspre_staload.hats"


staload UN = "prelude/SATS/unsafe.sats"


absvt@ype be = ptr
absvt@ype le = ptr


typedef u16 = uint16


extern fun{env:vt0p} rd16 ( env: &env >> _ ) : u16


assume be = @{a=int}
assume le = @{b=int}


implmnt main0 ( argc, argv ) : void =
    let val odd = argc % 2 = 0
        var env_be: be = @{a=0}
        var env_le: le = @{b=0}
    in
        if odd
            then let implmnt{be} rd16 ( env ) = $UN.cast{u16}(23) in (
                print!("be: ")
              ; println!(rd16(env_be))
            ) end
        else let implmnt{le} rd16 ( env ) = $UN.cast{u16}(42) in (
            print!("le: ")
          ; println!(rd16(env_le))
        ) end
    end
$ patscc -DATS_MEMALLOC_LIBC -Ofast -flto -o bp3 bp3.dats
$ ./bp3 x
be: 23
$ ./bp3 x y
le: 42

[Hongwei Xi]

(*
bp1.dats:
*)

// patscc -DATS_MEMALLOC_LIBC -Ofast -flto -o bp bp.dats


#include "share/atspre_staload.hats"


staload UN = "prelude/SATS/unsafe.sats"


absvt@ype be = ptr
absvt@ype le = ptr


typedef u16 = uint16


extern fun{env:vt0p} rd16 ( env: &env >> _ ) : u16

The code for bp1 should be written as follows:

(*

implmnt{be} rd16 ( env ) = $UN.cast{u16}(23)
implmnt{le} rd16 ( env ) = $UN.cast{u16}(42)

*)
implmnt
rd16<be> ( env ) = $UN.cast{u16}(23)
implmnt
rd16<le> ( env ) = $UN.cast{u16}(42)

assume be = @{a=int}
assume le = @{b=int}


implmnt main0 ( argc, argv ) : void =
    let val odd = argc % 2 = 0
        var env_be: be = @{a=0}
        var env_le: le = @{b=0}
    in
        if odd
            then (
                print!("be: ")

              ; println!(rd16<be>(env_be))

            )
        else (
            print!("le: ")

          ; println!(rd16<le>(env_le))
        )
    end

I will take a look at bp2 and bp3 later.

--
You received this message because you are subscribed to the Google Groups "ats-lang-users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to ats-lang-users+unsubscribe@googlegroups.com.
To post to this group, send email to ats-lang-users@googlegroups.com.
Visit this group at https://groups.google.com/group/ats-lang-users.
To view this discussion on the web visit https://groups.google.com/d/msgid/ats-lang-users/30790728-dfee-41b0-81ce-adefce142058%40googlegroups.com.

[Hongwei Xi]

Basically, the issue can be explained as follows:

If you write

implement{be} rd16(...) = ...

then 'be' is a bound variable, which can be instantiated

with any type.

What you need is to write

implement rd16<be> (...) = ...

where 'be' is treated as the abstract type you declared earlier.

To post to this group, send email to ats-lan...@googlegroups.com.

[n and]

thanks! stupid me. i got confused... i thought when using implement{x} it would do the instantiation env <-| x. 

definitely need more practice ;)

You received this message because you are subscribed to a topic in the Google Groups "ats-lang-users" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/ats-lang-users/NUtFyrpftlU/unsubscribe.
To unsubscribe from this group and all its topics, send an email to ats-lang-users+unsubscribe@googlegroups.com.
To post to this group, send email to ats-lang-users@googlegroups.com.

Visit this group at https://groups.google.com/group/ats-lang-users.

To view this discussion on the web visit https://groups.google.com/d/msgid/ats-lang-users/CAPPSPLqmJpvuUeZjzGxNpaG1HsG4Mpjxao%2BAkQ_6%3D0JDkraPuA%40mail.gmail.com.