Initializing statically-allocated arrays within templates

[M88]

Hello,

I was wondering if it's possible to use a template to define the size of a statically allocated array in a template.

An example (that won't compile) is:

extern

fun {a:t@ype} example () : void

extern

val {} example$bufsz  : [n:pos] size_t n

implement {a}

example () =

    let

          val sz = example$bufsz<>

          var buf = @[a?][sz]()

    in

    end

Is it possible to define example$bufsz<> as a constant with late-binding?  I suppose behavior like sizeof<a> would be ideal, but that seems to be internal.

Thanks,

-M

[Julian Fondren]

An option.

testarr.dats:

#include "share/atspre_staload.hats"

local
  #define example$bufsz 100
in
  #include "./testarr.hats"
end

implement main0() = example<int>()

testarr.hats:

extern fun {a:t@ype} example(): void

implement {a} example() =
  let
    val sz = example$bufsz
    var buf = @[a?][example$bufsz]()
  in end

[Hongwei Xi]

You can use a function template:

fun {} example$bufsz() : [n:pos] size_t n

Because of inlining, you should get what you wanted in the first place.

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[M88]

I get an error during C compilation, ATSERRORarrdim_unknown, when I try to use a template function.

Thanks Julian -- that's a decent solution.

[gmhwxi]

I see.

Then there isn't really a way to do this as the 'sz' in @[a?][sz]

is static.

I will keep an eye on it. Maybe I can find a way to support it in ATS3.

[Julian Fondren]

Slightly neater. Note that you can have cover (multiple; expressions) with a single where {}

#include "share/atspre_staload_hats."

implement main0() = example<int>() where {
  #define example$bufsz 100
  #include "./testarr.hats"
}

[M88]

Scoped includes and constants .... are....awesome.

On Tuesday, September 25, 2018 at 3:28:05 PM UTC-4, M88 wrote: