Forgot to uncomment.
Artyom is right. You could write the code as follows
(so as to avoid the need for type annotation):
implement utf8_to_unicode (pf | line, index, len, res) =
let
fun loop1 (c: char, mask: uint, bytes: uint): (uint, uint) =
if ((($UN.cast{uint}{char} c) land mask) != 0U)
then loop1 (c, mask >> 1, bytes + 1U)
else (mask, bytes)
fun loop2 {m:nat} (line: !strnptr(m), i: int, len: int(m), bytes: uint,
value: uint): uint =
undefined()
(* (* xxx TODO: Should implement following: *)
for (i = 1; i < bytes; i++) {
c = line[i];
if ((c & 0xc0) != 0x80)
return 1;
value = (value << 6) | (c & 0x3f);
}
*)
val c = line[index]
val () = !res := $UN.cast{unicode_t}{char} line[index]
(*
* 0xxxxxxx is valid utf8
* 10xxxxxx is invalid UTF-8, we assume it is Latin1
*)
in
if (c < $UN.cast{char}{int} 0xc0)
then 1U
else bytes' where {
(* Ok, it's 11xxxxxx, do a stupid decode *)
val (mask, bytes'') = loop1 (c, 0x20U, 0x2U)
(* Invalid? Do it as a single byte Latin1 *)
val bytes' = if (bytes'' > 6 || bytes'' > len)
then 1U
else bytes'' where {
(* Ok, do the bytes *)
val value = ($UN.cast{uint}{char} c) land (mask - 1U) // xxx TODO
val value = loop2 (line, 1, len, bytes'',
($UN.cast{uint}{char} c) land (mask - 1U))
val () = !res := $UN.cast{unicode_t}{uint} value
}
}
end
On Mon, Oct 29, 2018 at 8:14 AM Hongwei Xi <[email protected]> wrote:
> I tried and there was no problem. I used ATS2-0.3.12.
>
>
> On Mon, Oct 29, 2018 at 2:52 AM Kiwamu Okabe <[email protected]> wrote:
>
>> Dear all,
>>
>> Why following code occurs `unsolved constraint` error?
>>
>>
>> https://github.com/metasepi/uemacs-bohai/blob/8b2b657c829be1025433f3083aa5cf3b1d040cb6/DATS/utf8.dats#L60
>>
>> ```
>> $ vi DATS/utf8.dats
>> --snip--
>> implement utf8_to_unicode (pf | line, index, len, res) = bytes where {
>> fun loop1 (c: char, mask: uint, bytes: uint): (uint, uint) =
>> if ((($UN.cast{uint}{char} c) land mask) != 0U)
>> then loop1 (c, mask >> 1, bytes + 1U)
>> else (mask, bytes)
>>
>> fun loop2 {m:nat} (line: !strnptr(m), i: int, len: int(m), bytes:
>> uint, value: uint): uint =
>> undefined()
>>
>> val c = line[index]
>> val () = !res := $UN.cast{unicode_t}{char} line[index]
>>
>> (*
>> * 0xxxxxxx is valid utf8
>> * 10xxxxxx is invalid UTF-8, we assume it is Latin1
>> *)
>> val bytes = if (c < $UN.cast{char}{int} 0xc0)
>> then 1U
>> else bytes' where {
>> (* Ok, it's 11xxxxxx, do a stupid decode *)
>> val (mask, bytes'') = loop1 (c, 0x20U, 0x2U)
>>
>> (* Invalid? Do it as a single byte Latin1 *)
>> val bytes' = if (bytes'' > 6 || bytes'' > len)
>> then 1U
>> else bytes'' where {
>> (* Ok, do the bytes *)
>> val value = loop2 (line, 1, len, bytes'',
>> ($UN.cast{uint}{char} c) land (mask - 1U))
>> val () = !res := $UN.cast{unicode_t}{uint} value
>> }
>> }
>> }
>> --snip--
>> $ pwd
>> /home/kiwamu/src/uemacs-bohai
>> $ make
>> ATS utf8.dats.c
>> /home/kiwamu/src/uemacs-bohai/DATS/utf8.dats: 929(line=23, offs=58) --
>> 934(line=23, offs=63): error(3): unsolved constraint:
>> C3NSTRprop(C3TKmain(); S2Eeqeq(S2Evar(l$8600$8666(14318));
>> S2Evar(l$8600$8601(14253))))
>> /home/kiwamu/src/uemacs-bohai/DATS/utf8.dats: 929(line=23, offs=58) --
>> 934(line=23, offs=63): error(3): unsolved constraint for var
>> preservation
>> typechecking has failed: there are some unsolved constraints: please
>> inspect the above reported error message(s) for information.
>> exit(ATS): uncaught exception:
>>
>> _2home_2kiwamu_2src_2ATS_2dPostiats_2src_2pats_error_2esats__FatalErrorExn(1025)
>> make: *** [Makefile:75: utf8.dats.c] Error 1
>> ```
>>
>> Best regards,
>> --
>> Kiwamu Okabe at METASEPI DESIGN
>>
>> --
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>> .
>>
>
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