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 -- 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+unsubscr...@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/CAEvX6d%3DWqC8ym8KArMBvwOYi8tBqZAMJ_WwfXp0h9AgBkcO2Lw%40mail.gmail.com.
