print!/fprint! - how does it work?

[Artyom Shalkhakov]

I'd like to implement a similar macro but don't know how.

This is for binary printing of values (to write binary files easily if error reporting is of little concern). At first I thought that co-opting fprint_val/fprint_ref would be enough, but now I think the user would have to staload the overriden template instantiations for basic types (and a host of other types, e.g. lists, etc.), which can be quite puzzling.

[Hongwei Xi]

print! and fprint! are handled by the compiler in a special way:

https://github.com/githwxi/ATS-Postiats/blob/master/src/pats_trans1_syndef.dats

There is currently no support for doing this outside the compiler.

On Wed, Dec 23, 2015 at 10:33 PM, Artyom Shalkhakov <artyom.s...@gmail.com> wrote:

I'd like to implement a similar macro but don't know how.

This is for binary printing of values (to write binary files easily if error reporting is of little concern). At first I thought that co-opting fprint_val/fprint_ref would be enough, but now I think the user would have to staload the overriden template instantiations for basic types (and a host of other types, e.g. lists, etc.), which can be quite puzzling.

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[Artyom Shalkhakov]

On Thursday, December 24, 2015 at 10:08:25 AM UTC+6, gmhwxi wrote:

print! and fprint! are handled by the compiler in a special way:

https://github.com/githwxi/ATS-Postiats/blob/master/src/pats_trans1_syndef.dats

There is currently no support for doing this outside the compiler.

Thanks for the info. There is commented out code in $ATSHOME/prelude/lmacrodef.sats (the print_mac and println_mac). Can these be used instead of print! and println! ? I tried this code:

#include

"share/atspre_staload.hats"

local

macrodef

rec

auxlist

  (xs, y) =

(

//

if iscons! (xs) then

  `(print ,(car! xs); ,(auxlist (cdr! xs, y)))

else y // end of [if]

//

) // end of [auxlist]

in (* in of [local] *)

macdef

print_mac (x) =

,(

  if islist! (x) then auxlist (x, `()) else `(print ,(x))

) // end of [print_mac]

macdef

println_mac (x) =

,(

  if islist! (x)

    then auxlist (x, `(print_newline())) else `(print ,(x))

  // end of [if]

) // end of [println_mac]

end // end of [local]

implement

main0 () = {

  val () = println_mac ("the value is: ", 2*2)

}

and it yields:

admin@artyom-laptop:ats$patscc lmacrodeftest.dats

/home/admin/org/ats/lmacrodeftest.dats: 576(line=38, offs=12) -- 611(line=38, offs=47): error(mac): the form of dynamic expression [D2Esing(D2Eifhead(D2Emacfun(iscons; D2Evar(xs$3803(-1))); D2Emacsyn(MSKencode; D2Eseq(D2Eapplst(D2Esym(print); D2EXPARGdyn(-1; D2Emacsyn(MSKdecode; D2Emacfun(car; D2Evar(xs$3803(-1)))))), D2Emacsyn(MSKdecode; D2Eapplst(D2Emac(auxlist); D2EXPARGdyn(-1; D2Emacfun(cdr; D2Evar(xs$3803(-1))), D2Evar(y$3804(-1))))))); Some(D2Evar(y$3804(-1)))))] is unsupported for macro expansion.

/home/admin/org/ats/lmacrodeftest.dats: 576(line=38, offs=12) -- 611(line=38, offs=47): error(mac): the expansion of the dynamic expression at (/home/admin/org/ats/lmacrodeftest.dats: 391(line=29, offs=3) -- 466(line=30, offs=60)) is expected to return code (AST) but it does not.

/home/admin/org/ats/lmacrodeftest.dats: 571(line=38, offs=7) -- 573(line=38, offs=9): error(3): the void pattern is ill-typed.

/home/admin/org/ats/lmacrodeftest.dats: 571(line=38, offs=7) -- 573(line=38, offs=9): error(3): mismatch of static terms (tyleq):

The actual term is: S2Ecst(atsvoid_t0ype)

The needed term is: S2Eerr()

patsopt(TRANS3): there are [2] errors in total.

exit(ATS): uncaught exception: _2home_2admin_2postiats_2src_2pats_error_2esats__FatalErrorExn(1025)

[Hongwei Xi]

I see. I think this can be made to work as expected.

I need to do a bit reverse engineering to figure it out.

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[gmhwxi]

I did a very minor fix to make the print_mac example work.

See:

https://github.com/githwxi/ATS-Postiats-test/blob/master/core/MISC/test11.dats

The changes have been uploaded to the Github repo for ATS2.

On Thursday, December 24, 2015 at 10:09:38 AM UTC-5, gmhwxi wrote:

I see. I think this can be made to work as expected.

I need to do a bit reverse engineering to figure it out.

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