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add randomness predicates, small but consequential changes to TrailRef

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This commit is contained in:
Mark Thom
2019-10-17 00:21:21 -06:00
parent a641822a1b
commit ab9a14cc6a
6 changed files with 99 additions and 17 deletions
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5
src/prolog/machine/machine_indices.rs
View File

@@ -178,10 +178,11 @@ impl From<Ref> for Addr {
}
}
#[derive(Clone)]
#[derive(Clone, Copy)]
pub enum TrailRef {
Ref(Ref),
AttrVarLink(usize, Addr),
AttrVarHeapLink(usize),
AttrVarListLink(usize, usize),
}
impl From<Ref> for TrailRef {

28
src/prolog/machine/machine_state_impl.rs
View File

@@ -648,9 +648,15 @@ impl MachineState {
self.tr += 1;
}
}
TrailRef::AttrVarLink(h, prev_addr) => {
TrailRef::AttrVarHeapLink(h) => {
if h < self.hb {
self.trail.push(TrailRef::AttrVarLink(h, prev_addr));
self.trail.push(TrailRef::AttrVarHeapLink(h));
self.tr += 1;
}
}
TrailRef::AttrVarListLink(h, l) => {
if h < self.hb {
self.trail.push(TrailRef::AttrVarListLink(h, l));
self.tr += 1;
}
}
@@ -680,7 +686,7 @@ impl MachineState {
// additions, now that deleted attributes can be undeleted by
// backtracking.
for i in (a1..a2).rev() {
match self.trail[i].clone() {
match self.trail[i] {
TrailRef::Ref(Ref::HeapCell(h)) => {
self.heap[h] = HeapCellValue::Addr(Addr::HeapCell(h))
}
@@ -690,8 +696,11 @@ impl MachineState {
TrailRef::Ref(Ref::StackCell(fr, sc)) => {
self.and_stack[fr][sc] = Addr::StackCell(fr, sc)
}
TrailRef::AttrVarLink(h, prev_addr) => {
self.heap[h] = HeapCellValue::Addr(prev_addr)
TrailRef::AttrVarHeapLink(h) => {
self.heap[h] = HeapCellValue::Addr(Addr::HeapCell(h));
}
TrailRef::AttrVarListLink(h, l) => {
self.heap[h] = HeapCellValue::Addr(Addr::Lis(l));
}
}
}
@@ -735,13 +744,14 @@ impl MachineState {
let mut i = self.or_stack[b].tr;
while i < self.tr {
let tr_i = self.trail[i].clone();
let tr_i = self.trail[i];
let hb = self.hb;
match tr_i {
TrailRef::Ref(Ref::AttrVar(tr_i))
| TrailRef::Ref(Ref::HeapCell(tr_i))
| TrailRef::AttrVarLink(tr_i, _) => {
| TrailRef::Ref(Ref::HeapCell(tr_i))
| TrailRef::AttrVarHeapLink(tr_i)
| TrailRef::AttrVarListLink(tr_i, _) => {
if tr_i < hb {
i += 1;
} else {
@@ -765,7 +775,7 @@ impl MachineState {
i += 1;
} else {
let tr = self.tr;
let val = self.trail[tr - 1].clone();
let val = self.trail[tr - 1];
self.trail[i] = val;
self.trail.pop();
self.tr -= 1;

53
src/prolog/machine/system_calls.rs
View File

@@ -17,6 +17,8 @@ use crate::prolog::ordered_float::OrderedFloat;
use crate::prolog::read::{readline, PrologStream};
use crate::prolog::rug::Integer;
use crate::ref_thread_local::RefThreadLocal;
use indexmap::{IndexMap, IndexSet};
use std::collections::VecDeque;
@@ -679,7 +681,8 @@ impl MachineState {
let c = self.int_to_char_code(&n, "atom_codes", 2)?;
chars.push(c as char);
}
&Addr::Con(Constant::CharCode(c)) => chars.push(c as char),
&Addr::Con(Constant::CharCode(c)) =>
chars.push(c as char),
_ => {
let err = MachineError::type_error(
ValidType::Integer,
@@ -1018,8 +1021,14 @@ impl MachineState {
tail
};
let trail_ref = match old_addr {
Addr::HeapCell(h) => TrailRef::AttrVarHeapLink(h),
Addr::Lis(l) => TrailRef::AttrVarListLink(l1 + 1, l),
_ => unreachable!()
};
self.heap[l1 + 1] = HeapCellValue::Addr(tail);
self.trail(TrailRef::AttrVarLink(l1 + 1, old_addr));
self.trail(trail_ref);
}
}
}
@@ -1041,7 +1050,7 @@ impl MachineState {
};
self.heap[h + 1] = HeapCellValue::Addr(tail);
self.trail(TrailRef::AttrVarLink(h + 1, Addr::Lis(l)));
self.trail(TrailRef::AttrVarListLink(h + 1, l));
}
_ => unreachable!(),
}
@@ -1255,6 +1264,19 @@ impl MachineState {
_ => self.fail = true,
}
}
&SystemClauseType::Maybe => {
let result = {
let mut rand = RANDOM_STATE.borrow_mut();
if rand.bits(1) == 0 {
true
} else {
false
}
};
self.fail = result;
}
&SystemClauseType::OpDeclaration => {
let priority = self[temp_v!(1)].clone();
let specifier = self[temp_v!(2)].clone();
@@ -1834,6 +1856,31 @@ impl MachineState {
}
&SystemClauseType::SetBall =>
self.set_ball(),
&SystemClauseType::SetSeed => {
let seed = self.store(self.deref(self[temp_v!(1)].clone()));
let seed = match seed {
Addr::Con(Constant::Integer(n)) =>
n,
Addr::Con(Constant::CharCode(c)) =>
Integer::from(c),
Addr::Con(Constant::Rational(r)) => {
if r.denom() == &1 {
r.numer().clone()
} else {
self.fail = true;
return Ok(());
}
}
_ => {
self.fail = true;
return Ok(());
}
};
let mut rand = RANDOM_STATE.borrow_mut();
rand.seed(&seed);
}
&SystemClauseType::SkipMaxList =>
if let Err(err) = self.skip_max_list() {
return Err(err);