rishi/scryer-prolog
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

compare the tails of partial string prefixes in compare_pstr_prefixes (#883)

Browse Source
This commit is contained in:
Mark Thom
2021-03-22 12:44:58 -06:00
parent 1b9015a049
commit 233faea200
2 changed files with 60 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
src/machine/partial_string.rs
View File

@@ -278,7 +278,7 @@ impl<'a> Iterator for HeapPStrIter<'a> {
Addr::Con(h) if self.machine_st.heap.atom_at(h) => {
if let HeapCellValue::Atom(ref atom, _) = &self.machine_st.heap[h] {
if atom.is_char() {
Some(atom.as_str().chars().next().unwrap())
atom.as_str().chars().next()
} else {
None
}
@@ -400,11 +400,42 @@ pub(super) fn compare_pstr_prefixes<'a>(
}
}
return match (i1.focus(), i2.focus()) {
(Addr::EmptyList, Addr::EmptyList) => Some(Ordering::Equal),
(Addr::EmptyList, _) => Some(Ordering::Less),
(_, Addr::EmptyList) => Some(Ordering::Greater),
_ => None,
let ordering = if r1.is_none() {
mem::swap(&mut r1, &mut r2);
Ordering::Less
} else {
Ordering::Greater
};
let machine_st = i1.machine_st;
let check_focuses = || {
match (i1.focus(), i2.focus()) {
(Addr::EmptyList, Addr::EmptyList) => Some(Ordering::Equal),
(Addr::EmptyList, _) => Some(Ordering::Less),
(_, Addr::EmptyList) => Some(Ordering::Greater),
_ => None,
}
};
return match r1 {
Some(PStrIteratee::PStrSegment(h, n)) => {
if let &HeapCellValue::PartialString(ref pstr, _) = &machine_st.heap[h] {
if pstr.as_str_from(n).chars().next().is_some() {
Some(ordering)
} else {
check_focuses()
}
} else {
unreachable!()
}
}
Some(PStrIteratee::Char(_)) => {
Some(ordering)
}
None => {
check_focuses()
}
};
}
}