Polymorphic datatype

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1

unfortunately, I have problem when using separate files for this code

snippet.

If I use three files get_value.sats, get_value.dats and main.dats, I

cannot make it working…

— get_value.sats —

datatype color = Black | Red

datatype tree (a:t@ype) =

Empty(a) of ()

| Leaf(a) of (color, tree a, a, tree a)

fun{a:t@ype} add_x(w: a, x: a): a

fun{a:t@ype} get_value(t: tree a, x: a) : a

— get_value.dats —

staload “get_value.sats”

implement add_x(w,x) = w + x

implement add_x(w,x) = w + x

implement{a} get_value(t, x) = case+ t of

| Leaf(_, _, v0, _) => add_x(v0, x)

| _ => x

— main.dats —

staload “get_value.sats”

dynload “get_value.dats” // I put dynamic here so add_x defined in

get_value.dats can be seen

implement main(argc, argv) = () where {

val () = print(get_value(Leaf(Black, Empty, 10.1f, Empty),

3.14159f)) // for floats

val () = print_newline()

val () = print(get_value(Leaf(Black, Empty, 10, Empty), 31)) // for

integers

val () = print_newline()

}

I compile with : @ atscc -o test get_value.sats get_value.dats main.dats

and the error is : main.dats: 489(line=24, offs=18) – 505(line=24,

offs=34): error(ccomp): the template definition for [get_value] is
unavailable at [get_value$1696_ats_float_type].

You need to add a line:
staload “get_value.sats”
staload _(anon) = “get_value.dats” // add this one
dynload “get_value.dats” // I put dynamic here so add_x defined in
get_value.dats can be seen

I added the line but still have an error :
get_value.dats: 163(line=5, offs=26) – 168(line=5, offs=31): error(ccomp):
the template definition for [add_x] is unavailable at
[add_x$1695_ats_float_type].

2

great, I will use number.hats !
thanks

3

Say you rename number.hats as number2.hats. Feel free to modify it as you
wish.

4

Right, this is how we do it in ATS. It should be much easier to do this in
ATS2.

5

Note that the following files are available for use:

$ATSHOME/prelude/SATS/number.sats
$ATSHOME/prelude/HATS/number.hats

6

mm I have problems using number.hats with my OS which is FreeBSD.

the gcc compiler complains about lacking of complex functions missing
(undefined reference to `ccos’, …)

I suspect a problem with c99 complex extensions implementation in gcc. I
have posted a message in the FreeBSD forum.

Is that anyone using freeBSD with ATS here ?

Maybe it is possible to disable the complex feature in ATS in order to use
number.hats anyway ?

thanks

7

ok,
So I would make a separate file :

— numeric_gen.hats —
implement add_x(w,x) = w + x
implement add_x(w,x) = w + x

and include it from main.dats with :

#include “numeric_gen.hats”

thanks a lot !

8

Now I remember :slight_smile:

The following two lines needs to be moved to main.dats:

implement add_x(w,x) = w + x

implement add_x(w,x) = w + x

9

dynload “get_value.dats” // I put dynamic here so add_x defined in
get_value.dats can be seen

First, dynload is for doing some kind dynamic initialization of values.

You need

staload _ = “get_value.dats”

to make the template definitions available to the compiler.