rishi/scryer-prolog
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scryer-prolog/src/prolog/machine/machine_state_impl.rs

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Rust
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use prolog_parser::ast::*;
use prolog_parser::string_list::StringList;
use prolog::instructions::*;
use prolog::and_stack::*;
use prolog::copier::*;
use prolog::heap_iter::*;
use prolog::heap_print::*;
use prolog::machine::IndexStore;
use prolog::machine::machine_errors::*;
use prolog::machine::machine_state::*;
use prolog::num::{Integer, Signed, ToPrimitive, Zero};
use prolog::num::bigint::{BigInt, BigUint};
use prolog::num::rational::Ratio;
use prolog::or_stack::*;
use std::cmp::{max, Ordering};
use std::collections::{HashMap, HashSet};
use std::rc::Rc;
macro_rules! try_or_fail {
($s:ident, $e:expr) => {{
match $e {
Ok(val) => val,
Err(msg) => {
$s.throw_exception(msg);
return;
}
}
}}
}
impl MachineState {
pub(crate) fn new() -> Self {
MachineState {
s: 0,
p: CodePtr::default(),
b: 0,
b0: 0,
e: 0,
num_of_args: 0,
cp: LocalCodePtr::default(),
special_form_cp: CodePtr::default(),
fail: false,
heap: Heap::with_capacity(256),
mode: MachineMode::Write,
and_stack: AndStack::new(),
or_stack: OrStack::new(),
registers: vec![Addr::HeapCell(0); MAX_ARITY + 1], // self.registers[0] is never used.
trail: vec![],
pstr_trail: vec![],
pstr_tr: 0,
tr: 0,
hb: 0,
block: 0,
ball: Ball::new(),
interms: vec![Number::default(); 256],
last_call: false,
flags: MachineFlags::default()
}
}
#[allow(dead_code)]
pub fn print_heap(&self) {
for h in 0 .. self.heap.h {
println!("{} : {}", h, self.heap[h]);
}
}
#[inline]
pub fn machine_flags(&self) -> MachineFlags {
self.flags
}
fn next_global_index(&self) -> usize {
max(if self.and_stack.len() > 0 { self.and_stack[self.e].global_index } else { 0 },
if self.b > 0 { self.or_stack[self.b - 1].global_index } else { 0 }) + 1
}
pub(crate) fn store(&self, addr: Addr) -> Addr {
match addr {
Addr::AttrVar(h) | Addr::HeapCell(h) => self.heap[h].as_addr(h),
Addr::StackCell(fr, sc) => self.and_stack[fr][sc].clone(),
addr => addr
}
}
pub(crate) fn deref(&self, mut addr: Addr) -> Addr {
loop {
let value = self.store(addr.clone());
if value.is_ref() && value != addr {
addr = value;
continue;
}
return addr;
};
}
fn bind_attr_var(&mut self, h: usize, addr: Addr) {
match addr.as_var() {
Some(Ref::HeapCell(hc)) => {
self.heap[hc] = HeapCellValue::Addr(Addr::AttrVar(h));
self.trail(TrailRef::from(Ref::HeapCell(hc)));
},
Some(Ref::StackCell(fr, sc)) => {
self.and_stack[fr][sc] = Addr::AttrVar(h);
self.trail(TrailRef::from(Ref::StackCell(fr, sc)));
},
_ => {
// TODO: set up writing to the attribute queue here.
self.heap[h] = HeapCellValue::Addr(addr);
self.trail(TrailRef::from(Ref::AttrVar(h)));
}
}
}
pub(super) fn bind(&mut self, r1: Ref, a2: Addr) {
let t1 = self.store(r1.as_addr());
let t2 = self.store(a2.clone());
if t1.is_ref() && (!t2.is_ref() || a2 < r1) {
match r1 {
Ref::StackCell(fr, sc) =>
self.and_stack[fr][sc] = t2,
Ref::HeapCell(h) =>
self.heap[h] = HeapCellValue::Addr(t2),
Ref::AttrVar(h) =>
return self.bind_attr_var(h, t2)
};
self.trail(TrailRef::from(r1));
} else {
match a2.as_var() {
Some(Ref::StackCell(fr, sc)) => {
self.and_stack[fr][sc] = t1;
self.trail(TrailRef::Ref(Ref::StackCell(fr, sc)));
},
Some(Ref::HeapCell(h)) => {
self.heap[h] = HeapCellValue::Addr(t1);
self.trail(TrailRef::Ref(Ref::HeapCell(h)));
},
Some(Ref::AttrVar(h)) =>
return self.bind_attr_var(h, t1),
None => {}
}
}
}
pub(super)
fn print_var_eq<Outputter>(&self, var: Rc<Var>, addr: Addr, var_dir: &HeapVarDict,
mut output: Outputter)
-> Outputter
where Outputter: HCValueOutputter
{
let orig_len = output.len();
output.begin_new_var();
output.append(var.as_str());
output.append(" = ");
let mut printer = HCPrinter::from_heap_locs(&self, output, var_dir);
printer.numbervars = false;
printer.quoted = true;
let mut output = printer.print(addr);
let bad_ending = format!("= {}", &var);
if output.ends_with(&bad_ending) {
output.truncate(orig_len);
}
output
}
pub(super)
fn print_exception<Outputter>(&self, addr: Addr, var_dir: &HeapVarDict, output: Outputter)
-> Outputter
where Outputter: HCValueOutputter
{
let printer = HCPrinter::from_heap_locs(&self, output, var_dir);
printer.print(addr)
}
pub(super)
fn unify_string(&mut self, pdl: &mut Vec<Addr>, s1: &mut StringList, s2: &mut StringList) -> bool
{
if let Some(c1) = s1.head() {
if let Some(c2) = s2.head() {
if c1 == c2 {
pdl.push(Addr::Con(Constant::String(s1.tail())));
pdl.push(Addr::Con(Constant::String(s2.tail())));
return true;
}
} else if s2.is_expandable() {
self.pstr_trail(s2.clone());
pdl.push(Addr::Con(Constant::String(s2.push_char(c1))));
pdl.push(Addr::Con(Constant::String(s1.tail())));
return true;
}
} else if s1.is_expandable() {
if let Some(c) = s2.head() {
self.pstr_trail(s1.clone());
pdl.push(Addr::Con(Constant::String(s1.push_char(c))));
pdl.push(Addr::Con(Constant::String(s2.tail())));
} else if s2.is_expandable() {
return s1 == s2;
} else {
self.pstr_trail(s1.clone());
s1.set_expandable(false);
}
return true;
} else if s2.head().is_none() {
if s2.is_expandable() {
self.pstr_trail(s2.clone());
}
s2.set_expandable(false);
return true;
}
false
}
pub(super) fn unify(&mut self, a1: Addr, a2: Addr) {
let mut pdl = vec![a1, a2];
self.fail = false;
while !(pdl.is_empty() || self.fail) {
let d1 = self.deref(pdl.pop().unwrap());
let d2 = self.deref(pdl.pop().unwrap());
if d1 != d2 {
match (self.store(d1.clone()), self.store(d2.clone())) {
(Addr::AttrVar(h), addr) | (addr, Addr::AttrVar(h)) =>
self.bind(Ref::AttrVar(h), addr),
(Addr::HeapCell(h), _) =>
self.bind(Ref::HeapCell(h), d2),
(_, Addr::HeapCell(h)) =>
self.bind(Ref::HeapCell(h), d1),
(Addr::StackCell(fr, sc), _) =>
self.bind(Ref::StackCell(fr, sc), d2),
(_, Addr::StackCell(fr, sc)) =>
self.bind(Ref::StackCell(fr, sc), d1),
(Addr::Lis(a1), Addr::Str(a2)) | (Addr::Str(a2), Addr::Lis(a1)) => {
if let &HeapCellValue::NamedStr(n2, ref f2, _) = &self.heap[a2] {
if f2.as_str() == "." && n2 == 2 {
pdl.push(Addr::HeapCell(a1));
pdl.push(Addr::HeapCell(a2 + 1));
pdl.push(Addr::HeapCell(a1 + 1));
pdl.push(Addr::HeapCell(a2 + 2));
continue;
}
}
self.fail = true;
},
(Addr::Lis(a1), Addr::Con(Constant::String(ref mut s)))
| (Addr::Con(Constant::String(ref mut s)), Addr::Lis(a1))
if self.flags.double_quotes.is_chars() => {
if let Some(c) = s.head() {
pdl.push(Addr::Con(Constant::String(s.tail())));
pdl.push(Addr::HeapCell(a1 + 1));
pdl.push(Addr::Con(Constant::Char(c)));
pdl.push(Addr::HeapCell(a1));
continue;
} else if s.is_expandable() {
let prev_s = s.clone();
let mut stepper = |c| {
let new_s = s.push_char(c);
pdl.push(Addr::HeapCell(a1 + 1));
pdl.push(Addr::Con(Constant::String(new_s)));
};
match self.heap[a1].clone() {
HeapCellValue::Addr(Addr::Con(Constant::Char(c))) => {
self.pstr_trail(prev_s);
stepper(c);
continue;
},
HeapCellValue::Addr(Addr::Con(Constant::Atom(ref a, _))) =>
if let Some(c) = a.as_str().chars().next() {
if c.len_utf8() == a.as_str().len() {
self.pstr_trail(prev_s);
stepper(c);
continue;
}
},
_ => {}
};
}
self.fail = true;
},
(Addr::Con(Constant::EmptyList), Addr::Con(Constant::String(ref s)))
| (Addr::Con(Constant::String(ref s)), Addr::Con(Constant::EmptyList))
if self.flags.double_quotes.is_chars() => {
if s.is_expandable() && s.is_empty() {
self.pstr_trail(s.clone());
s.set_expandable(false);
continue;
}
self.fail = !s.is_empty();
},
(Addr::Lis(a1), Addr::Lis(a2)) => {
pdl.push(Addr::HeapCell(a1));
pdl.push(Addr::HeapCell(a2));
pdl.push(Addr::HeapCell(a1 + 1));
pdl.push(Addr::HeapCell(a2 + 1));
},
(Addr::Con(Constant::String(ref mut s1)),
Addr::Con(Constant::String(ref mut s2))) =>
self.fail = !(self.unify_string(&mut pdl, s1, s2)
|| self.unify_string(&mut pdl, s2, s1)),
(Addr::Con(ref c1), Addr::Con(ref c2)) =>
if c1 != c2 {
self.fail = true;
},
(Addr::Str(a1), Addr::Str(a2)) => {
let r1 = &self.heap[a1];
let r2 = &self.heap[a2];
if let &HeapCellValue::NamedStr(n1, ref f1, _) = r1 {
if let &HeapCellValue::NamedStr(n2, ref f2, _) = r2 {
if n1 == n2 && *f1 == *f2 {
for i in 1 .. n1 + 1 {
pdl.push(Addr::HeapCell(a1 + i));
pdl.push(Addr::HeapCell(a2 + i));
}
continue;
}
}
}
self.fail = true;
},
_ => self.fail = true
};
}
}
}
#[inline]
fn pstr_trail(&mut self, s: StringList) {
if let Some((prev_b, prev_s, _)) = self.pstr_trail.last().cloned() {
if prev_b == self.b && prev_s == s {
return;
}
}
let truncate_end = s.len() + s.cursor();
self.pstr_trail.push((self.b, s, truncate_end));
self.pstr_tr += 1;
}
pub(super) fn trail(&mut self, r: TrailRef) {
match r {
TrailRef::Ref(Ref::HeapCell(h)) =>
if h < self.hb {
self.trail.push(TrailRef::Ref(Ref::HeapCell(h)));
self.tr += 1;
},
TrailRef::Ref(Ref::AttrVar(h)) =>
if h < self.hb {
self.trail.push(TrailRef::Ref(Ref::AttrVar(h)));
self.tr += 1;
},
TrailRef::AttrVarLink(h, prev_addr) =>
if h < self.hb {
self.trail.push(TrailRef::AttrVarLink(h, prev_addr));
self.tr += 1;
},
TrailRef::Ref(Ref::StackCell(fr, sc)) => {
let fr_gi = self.and_stack[fr].global_index;
let b_gi = if !self.or_stack.is_empty() {
if self.b > 0 {
let b = self.b - 1;
self.or_stack[b].global_index
} else {
0
}
} else {
0
};
if fr_gi < b_gi {
self.trail.push(TrailRef::Ref(Ref::StackCell(fr, sc)));
self.tr += 1;
}
}
}
}
pub(super) fn unwind_trail(&mut self, a1: usize, a2: usize) {
// the sequence is reversed to respect the chronology of trail
// additions, now that deleted attributes can be undeleted by
// backtracking.
for i in (a1 .. a2).rev() {
match self.trail[i].clone() {
TrailRef::Ref(Ref::HeapCell(h)) =>
self.heap[h] = HeapCellValue::Addr(Addr::HeapCell(h)),
TrailRef::Ref(Ref::AttrVar(h)) =>
self.heap[h] = HeapCellValue::Addr(Addr::AttrVar(h)),
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)
}
}
}
pub(super) fn unwind_pstr_trail(&mut self, a1: usize, a2: usize) {
for i in a1 .. a2 {
let (_, mut s, end) = self.pstr_trail[i].clone();
s.truncate(end);
}
}
pub(super) fn tidy_pstr_trail(&mut self) {
if self.b == 0 {
return;
}
let b = self.b - 1;
let mut i = self.or_stack[b].pstr_tr;
while i < self.pstr_tr {
let str_b = self.pstr_trail[i].0;
if b < str_b {
let pstr_tr = self.pstr_tr;
let val = self.pstr_trail[pstr_tr - 1].clone();
self.pstr_trail[i] = val;
self.pstr_tr -= 1;
} else {
i += 1;
}
}
}
pub(super) fn tidy_trail(&mut self) {
if self.b == 0 {
return;
}
let b = self.b - 1;
let mut i = self.or_stack[b].tr;
while i < self.tr {
let tr_i = self.trail[i].clone();
let hb = self.hb;
match tr_i {
TrailRef::Ref(Ref::AttrVar(tr_i))
| TrailRef::Ref(Ref::HeapCell(tr_i))
| TrailRef::AttrVarLink(tr_i, _) =>
if tr_i < hb {
i += 1;
} else {
let tr = self.tr;
let val = self.trail[tr - 1].clone();
self.trail[i] = val;
self.trail.pop();
self.tr -= 1;
},
TrailRef::Ref(Ref::StackCell(fr, _)) => {
let b = self.b - 1;
let fr_gi = self.and_stack[fr].global_index;
let b_gi = if !self.or_stack.is_empty() {
self.or_stack[b].global_index
} else {
0
};
if fr_gi < b_gi {
i += 1;
} else {
let tr = self.tr;
let val = self.trail[tr - 1].clone();
self.trail[i] = val;
self.trail.pop();
self.tr -= 1;
}
}
};
}
}
#[inline]
fn write_char_to_string(&mut self, s: &mut StringList, c: char) -> bool {
self.pstr_trail(s.clone());
let new_s = s.push_char(c);
self.heap.push(HeapCellValue::Addr(Addr::Con(Constant::String(new_s))));
false
}
pub(super) fn write_constant_to_var(&mut self, addr: Addr, c: Constant) {
match self.store(self.deref(addr)) {
Addr::Con(Constant::String(ref mut s)) =>
self.fail = match c {
Constant::EmptyList if self.flags.double_quotes.is_chars() =>
!s.is_empty(),
Constant::String(ref s2)
if s.is_expandable() && s2.starts_with(s) => {
self.pstr_trail(s.clone());
s.append_suffix(s2);
s.set_expandable(s2.is_expandable());
false
},
Constant::String(s2) => *s != s2,
Constant::Atom(ref a, _)
if a.as_str().starts_with(&s.borrow()[s.cursor() ..]) =>
if let Some(c) = a.as_str().chars().next() {
if c.len_utf8() == a.as_str().len() {
// detect chars masquerading as atoms.
if s.is_empty() {
self.write_char_to_string(s, c);
}
false
} else {
true
}
} else {
true
},
Constant::Char(ref c) if s.is_empty() && s.is_expandable() =>
self.write_char_to_string(s, *c),
Constant::Char(ref c) =>
if s.borrow().chars().next() == Some(*c) && c.len_utf8() == s.len() {
s.set_expandable(false);
false
} else {
true
},
_ => true
},
Addr::Con(c1) =>
if c1 != c {
self.fail = true;
},
addr => if let Some(r) = addr.as_var() {
self.bind(r, Addr::Con(c));
} else {
self.fail = true;
}
};
}
pub(super) fn get_number(&self, at: &ArithmeticTerm) -> Result<Number, MachineStub> {
match at {
&ArithmeticTerm::Reg(r) => self.arith_eval_by_metacall(r),
&ArithmeticTerm::Interm(i) => Ok(self.interms[i-1].clone()),
&ArithmeticTerm::Number(ref n) => Ok(n.clone()),
}
}
fn get_rational(&self, at: &ArithmeticTerm, caller: &MachineStub)
-> Result<Rc<Ratio<BigInt>>, MachineStub>
{
let n = self.get_number(at)?;
match n {
Number::Rational(r) => Ok(r),
Number::Float(fl) =>
if let Some(r) = Ratio::from_float(fl.into_inner()) {
Ok(Rc::new(r))
} else {
Err(self.error_form(MachineError::instantiation_error(), caller.clone()))
},
Number::Integer(bi) =>
Ok(Rc::new(Ratio::from_integer((*bi).clone())))
}
}
fn signed_bitwise_op<Op>(&self, n1: &BigInt, n2: &BigInt, f: Op) -> Rc<BigInt>
where Op: FnOnce(&BigUint, &BigUint) -> BigUint
{
let n1_b = n1.to_signed_bytes_le();
let n2_b = n2.to_signed_bytes_le();
let u_n1 = BigUint::from_bytes_le(&n1_b);
let u_n2 = BigUint::from_bytes_le(&n2_b);
Rc::new(BigInt::from_signed_bytes_le(&f(&u_n1, &u_n2).to_bytes_le()))
}
pub(super) fn arith_eval_by_metacall(&self, r: RegType) -> Result<Number, MachineStub>
{
let a = self[r].clone();
let caller = MachineError::functor_stub(clause_name!("(is)"), 2);
let mut interms: Vec<Number> = Vec::with_capacity(64);
for heap_val in self.post_order_iter(a) {
match heap_val {
HeapCellValue::NamedStr(2, name, Some(_)) => {
let a2 = interms.pop().unwrap();
let a1 = interms.pop().unwrap();
match name.as_str() {
"+" => interms.push(a1 + a2),
"-" => interms.push(a1 - a2),
"*" => interms.push(a1 * a2),
"/" => interms.push(self.div(a1, a2)?),
"**" => interms.push(self.pow(a1, a2)?),
"rdiv" => {
let r1 = self.get_rational(&ArithmeticTerm::Number(a1), &caller)?;
let r2 = self.get_rational(&ArithmeticTerm::Number(a2), &caller)?;
let result = Number::Rational(self.rdiv(r1, r2)?);
interms.push(result)
},
"//" => interms.push(Number::Integer(self.idiv(a1, a2)?)),
"div" => interms.push(Number::Integer(self.fidiv(a1, a2)?)),
">>" => interms.push(Number::Integer(self.shr(a1, a2)?)),
"<<" => interms.push(Number::Integer(self.shl(a1, a2)?)),
"/\\" => interms.push(Number::Integer(self.and(a1, a2)?)),
"\\/" => interms.push(Number::Integer(self.or(a1, a2)?)),
"xor" => interms.push(Number::Integer(self.xor(a1, a2)?)),
"mod" => interms.push(Number::Integer(self.modulus(a1, a2)?)),
"rem" => interms.push(Number::Integer(self.remainder(a1, a2)?)),
_ => return Err(self.error_form(MachineError::instantiation_error(),
caller))
}
},
HeapCellValue::NamedStr(1, name, Some(_)) => {
let a1 = interms.pop().unwrap();
match name.as_str() {
"-" => interms.push(- a1),
_ => return Err(self.error_form(MachineError::instantiation_error(),
caller))
}
},
HeapCellValue::Addr(Addr::Con(Constant::Number(n))) =>
interms.push(n),
_ =>
return Err(self.error_form(MachineError::instantiation_error(), caller))
}
};
Ok(interms.pop().unwrap())
}
fn rdiv(&self, r1: Rc<Ratio<BigInt>>, r2: Rc<Ratio<BigInt>>)
-> Result<Rc<Ratio<BigInt>>, MachineStub>
{
let stub = MachineError::functor_stub(clause_name!("(rdiv)"), 2);
if *r2 == Ratio::zero() {
Err(self.error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
} else {
Ok(Rc::new(&*r1 / &*r2))
}
}
fn fidiv(&self, n1: Number, n2: Number) -> Result<Rc<BigInt>, MachineStub>
{
let stub = MachineError::functor_stub(clause_name!("(div)"), 2);
match (n1, n2) {
(Number::Integer(n1), Number::Integer(n2)) =>
if *n2 == BigInt::zero() {
Err(self.error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
} else {
Ok(Rc::new(n1.div_floor(&n2)))
},
(Number::Integer(_), n2) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n2))),
stub)),
(n1, _) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n1))),
stub))
}
}
fn idiv(&self, n1: Number, n2: Number) -> Result<Rc<BigInt>, MachineStub>
{
let stub = MachineError::functor_stub(clause_name!("(//)"), 2);
match (n1, n2) {
(Number::Integer(n1), Number::Integer(n2)) =>
if *n2 == BigInt::zero() {
Err(self.error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
} else {
Ok(Rc::new(&*n1 / &*n2))
},
(Number::Integer(_), n2) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n2))),
stub)),
(n1, _) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n1))),
stub))
}
}
fn div(&self, n1: Number, n2: Number) -> Result<Number, MachineStub>
{
let stub = MachineError::functor_stub(clause_name!("(/)"), 2);
if n2.is_zero() {
Err(self.error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
} else {
Ok(n1 / n2)
}
}
fn pow(&self, n1: Number, n2: Number) -> Result<Number, MachineStub>
{
match n1.pow(n2) {
Ok(result) => Ok(result),
Err(_) => {
let stub = MachineError::functor_stub(clause_name!("**"), 2);
Err(self.error_form(MachineError::evaluation_error(EvalError::NoRoots),
stub))
}
}
}
fn shr(&self, n1: Number, n2: Number) -> Result<Rc<BigInt>, MachineStub>
{
let stub = MachineError::functor_stub(clause_name!("(>>)"), 2);
match (n1, n2) {
(Number::Integer(n1), Number::Integer(n2)) =>
match n2.to_usize() {
Some(n2) => Ok(Rc::new(&*n1 >> n2)),
_ => Ok(Rc::new(&*n1 >> usize::max_value()))
},
(Number::Integer(_), n2) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n2))),
stub)),
(n1, _) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n1))),
stub))
}
}
fn shl(&self, n1: Number, n2: Number) -> Result<Rc<BigInt>, MachineStub>
{
let stub = MachineError::functor_stub(clause_name!("(<<)"), 2);
match (n1, n2) {
(Number::Integer(n1), Number::Integer(n2)) =>
match n2.to_usize() {
Some(n2) => Ok(Rc::new(&*n1 << n2)),
_ => Ok(Rc::new(&*n1 << usize::max_value()))
},
(Number::Integer(_), n2) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n2))),
stub)),
(n1, _) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n1))),
stub))
}
}
fn xor(&self, n1: Number, n2: Number) -> Result<Rc<BigInt>, MachineStub>
{
let stub = MachineError::functor_stub(clause_name!("(xor)"), 2);
match (n1, n2) {
(Number::Integer(n1), Number::Integer(n2)) =>
Ok(self.signed_bitwise_op(&*n1, &*n2, |u_n1, u_n2| u_n1 ^ u_n2)),
(Number::Integer(_), n2) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n2))),
stub)),
(n1, _) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n1))),
stub))
}
}
fn and(&self, n1: Number, n2: Number) -> Result<Rc<BigInt>, MachineStub>
{
let stub = MachineError::functor_stub(clause_name!("(/\\)"), 2);
match (n1, n2) {
(Number::Integer(n1), Number::Integer(n2)) =>
Ok(self.signed_bitwise_op(&*n1, &*n2, |u_n1, u_n2| u_n1 & u_n2)),
(Number::Integer(_), n2) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n2))),
stub)),
(n1, _) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n1))),
stub))
}
}
fn modulus(&self, n1: Number, n2: Number) -> Result<Rc<BigInt>, MachineStub>
{
let stub = MachineError::functor_stub(clause_name!("(mod)"), 2);
match (n1, n2) {
(Number::Integer(n1), Number::Integer(n2)) =>
if *n2 == BigInt::zero() {
Err(self.error_form(MachineError::evaluation_error(EvalError::ZeroDivisor),
stub))
} else {
Ok(Rc::new(n1.mod_floor(&n2)))
},
(Number::Integer(_), n2) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n2))),
stub)),
(n1, _) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n1))),
stub))
}
}
fn remainder(&self, n1: Number, n2: Number) -> Result<Rc<BigInt>, MachineStub>
{
let stub = MachineError::functor_stub(clause_name!("(rem)"), 2);
match (n1, n2) {
(Number::Integer(n1), Number::Integer(n2)) =>
if *n2 == BigInt::zero() {
Err(self.error_form(MachineError::evaluation_error(EvalError::ZeroDivisor),
stub))
} else {
Ok(Rc::new(&*n1 % &*n2))
},
(Number::Integer(_), n2) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n2))),
stub)),
(n1, _) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n1))),
stub))
}
}
fn or(&self, n1: Number, n2: Number) -> Result<Rc<BigInt>, MachineStub>
{
let stub = MachineError::functor_stub(clause_name!("(\\/)"), 2);
match (n1, n2) {
(Number::Integer(n1), Number::Integer(n2)) =>
Ok(self.signed_bitwise_op(&*n1, &*n2, |u_n1, u_n2| u_n1 & u_n2)),
(Number::Integer(_), n2) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n2))),
stub)),
(n1, _) =>
Err(self.error_form(MachineError::type_error(ValidType::Integer,
Addr::Con(Constant::Number(n1))),
stub))
}
}
pub(super) fn execute_arith_instr(&mut self, instr: &ArithmeticInstruction) {
match instr {
&ArithmeticInstruction::Add(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = n1 + n2;
self.p += 1;
},
&ArithmeticInstruction::Sub(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = n1 - n2;
self.p += 1;
},
&ArithmeticInstruction::Mul(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = n1 * n2;
self.p += 1;
},
&ArithmeticInstruction::Pow(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = try_or_fail!(self, self.pow(n1, n2));
self.p += 1;
},
&ArithmeticInstruction::RDiv(ref a1, ref a2, t) => {
let stub = MachineError::functor_stub(clause_name!("(rdiv)"), 2);
let r1 = try_or_fail!(self, self.get_rational(a1, &stub));
let r2 = try_or_fail!(self, self.get_rational(a2, &stub));
self.interms[t - 1] = Number::Rational(try_or_fail!(self, self.rdiv(r1, r2)));
self.p += 1;
},
&ArithmeticInstruction::FIDiv(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = Number::Integer(try_or_fail!(self, self.fidiv(n1, n2)));
self.p += 1;
},
&ArithmeticInstruction::IDiv(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = Number::Integer(try_or_fail!(self, self.idiv(n1, n2)));
self.p += 1;
},
&ArithmeticInstruction::Abs(ref a1, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
self.interms[t - 1] = n1.abs();
self.p += 1;
},
&ArithmeticInstruction::Neg(ref a1, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
self.interms[t - 1] = - n1;
self.p += 1;
},
&ArithmeticInstruction::Div(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = try_or_fail!(self, self.div(n1, n2));
self.p += 1;
},
&ArithmeticInstruction::Shr(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = Number::Integer(try_or_fail!(self, self.shr(n1, n2)));
self.p += 1;
},
&ArithmeticInstruction::Shl(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = Number::Integer(try_or_fail!(self, self.shl(n1, n2)));
self.p += 1;
},
&ArithmeticInstruction::Xor(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = Number::Integer(try_or_fail!(self, self.xor(n1, n2)));
self.p += 1;
},
&ArithmeticInstruction::And(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = Number::Integer(try_or_fail!(self, self.and(n1, n2)));
self.p += 1;
},
&ArithmeticInstruction::Or(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = Number::Integer(try_or_fail!(self, self.or(n1, n2)));
self.p += 1;
},
&ArithmeticInstruction::Mod(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = Number::Integer(try_or_fail!(self, self.modulus(n1, n2)));
self.p += 1;
},
&ArithmeticInstruction::Rem(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.interms[t - 1] = Number::Integer(try_or_fail!(self, self.remainder(n1, n2)));
self.p += 1;
}
};
}
pub(super) fn execute_fact_instr(&mut self, instr: &FactInstruction) {
match instr {
&FactInstruction::GetConstant(_, ref c, reg) => {
let addr = self[reg].clone();
self.write_constant_to_var(addr, c.clone());
},
&FactInstruction::GetList(_, reg) => {
let addr = self.store(self.deref(self[reg].clone()));
match addr {
Addr::Con(Constant::String(ref s))
if self.flags.double_quotes.is_chars() => {
let h = self.heap.h;
if let Some(c) = s.head() {
self.heap.push(HeapCellValue::Addr(Addr::Con(Constant::Char(c))));
self.heap.push(HeapCellValue::Addr(Addr::Con(Constant::String(s.tail()))));
self.s = h;
self.mode = MachineMode::Read;
} else if s.is_expandable() {
self.heap.push(HeapCellValue::Addr(Addr::Con(Constant::String(s.clone()))));
self.s = h;
self.mode = MachineMode::Read;
} else {
self.fail = true;
}
},
addr @ Addr::AttrVar(_) | addr @ Addr::StackCell(..) | addr @ Addr::HeapCell(_) => {
let h = self.heap.h;
self.heap.push(HeapCellValue::Addr(Addr::Lis(h+1)));
self.bind(addr.as_var().unwrap(), Addr::HeapCell(h));
self.mode = MachineMode::Write;
},
Addr::Lis(a) => {
self.s = a;
self.mode = MachineMode::Read;
},
_ => self.fail = true
};
},
&FactInstruction::GetStructure(ref ct, arity, reg) => {
let addr = self.deref(self[reg].clone());
match self.store(addr.clone()) {
Addr::Str(a) => {
let result = &self.heap[a];
if let &HeapCellValue::NamedStr(narity, ref s, _) = result {
if narity == arity && ct.name() == *s {
self.s = a + 1;
self.mode = MachineMode::Read;
} else {
self.fail = true;
}
}
},
Addr::AttrVar(_) | Addr::HeapCell(_) | Addr::StackCell(_, _) => {
let h = self.heap.h;
self.heap.push(HeapCellValue::Addr(Addr::Str(h + 1)));
self.heap.push(HeapCellValue::NamedStr(arity, ct.name(), ct.spec()));
self.bind(addr.as_var().unwrap(), Addr::HeapCell(h));
self.mode = MachineMode::Write;
},
_ => self.fail = true
};
},
&FactInstruction::GetVariable(norm, arg) =>
self[norm] = self.registers[arg].clone(),
&FactInstruction::GetValue(norm, arg) => {
let norm_addr = self[norm].clone();
let reg_addr = self.registers[arg].clone();
self.unify(norm_addr, reg_addr);
},
&FactInstruction::UnifyConstant(ref c) => {
match self.mode {
MachineMode::Read => {
let addr = Addr::HeapCell(self.s);
self.write_constant_to_var(addr, c.clone());
},
MachineMode::Write => {
self.heap.push(HeapCellValue::Addr(Addr::Con(c.clone())));
}
};
self.s += 1;
},
&FactInstruction::UnifyVariable(reg) => {
match self.mode {
MachineMode::Read =>
self[reg] = self.heap[self.s].as_addr(self.s),
MachineMode::Write => {
let h = self.heap.h;
self.heap.push(HeapCellValue::Addr(Addr::HeapCell(h)));
self[reg] = Addr::HeapCell(h);
}
};
self.s += 1;
},
&FactInstruction::UnifyLocalValue(reg) => {
let s = self.s;
match self.mode {
MachineMode::Read => {
let reg_addr = self[reg].clone();
self.unify(reg_addr, Addr::HeapCell(s));
},
MachineMode::Write => {
let addr = self.deref(self[reg].clone());
let h = self.heap.h;
if let Addr::HeapCell(hc) = addr {
if hc < h {
let val = self.heap[hc].clone();
self.heap.push(val);
self.s += 1;
return;
}
}
self.heap.push(HeapCellValue::Addr(Addr::HeapCell(h)));
self.bind(Ref::HeapCell(h), addr);
}
};
self.s += 1;
},
&FactInstruction::UnifyValue(reg) => {
let s = self.s;
match self.mode {
MachineMode::Read => {
let reg_addr = self[reg].clone();
self.unify(reg_addr, Addr::HeapCell(s));
},
MachineMode::Write => {
let heap_val = self.store(self[reg].clone());
self.heap.push(HeapCellValue::Addr(heap_val));
}
};
self.s += 1;
},
&FactInstruction::UnifyVoid(n) => {
match self.mode {
MachineMode::Read =>
self.s += n,
MachineMode::Write => {
let h = self.heap.h;
for i in h .. h + n {
self.heap.push(HeapCellValue::Addr(Addr::HeapCell(i)));
}
}
};
}
};
}
pub(super) fn execute_indexing_instr(&mut self, instr: &IndexingInstruction) {
match instr {
&IndexingInstruction::SwitchOnTerm(v, c, l, s) => {
let a1 = self.registers[1].clone();
let addr = self.store(self.deref(a1));
let offset = match addr {
Addr::HeapCell(_) | Addr::StackCell(..) | Addr::AttrVar(..) => v,
Addr::Con(Constant::String(_)) if self.flags.double_quotes.is_chars() => l,
Addr::Con(_) => c,
Addr::Lis(_) => l,
Addr::Str(_) => s,
};
match offset {
0 => self.fail = true,
o => self.p += o
};
},
&IndexingInstruction::SwitchOnConstant(_, ref hm) => {
let a1 = self.registers[1].clone();
let addr = self.store(self.deref(a1));
let offset = match addr {
Addr::Con(constant) => {
match hm.get(&constant) {
Some(offset) => *offset,
_ => 0
}
},
_ => 0
};
match offset {
0 => self.fail = true,
o => self.p += o,
};
},
&IndexingInstruction::SwitchOnStructure(_, ref hm) => {
let a1 = self.registers[1].clone();
let addr = self.store(self.deref(a1));
let offset = match addr {
Addr::Str(s) => {
if let &HeapCellValue::NamedStr(arity, ref name, _) = &self.heap[s] {
match hm.get(&(name.clone(), arity)) {
Some(offset) => *offset,
_ => 0
}
} else {
0
}
},
_ => 0
};
match offset {
0 => self.fail = true,
o => self.p += o
};
}
};
}
pub(super) fn execute_query_instr(&mut self, instr: &QueryInstruction) {
match instr {
&QueryInstruction::GetVariable(norm, arg) =>
self[norm] = self.registers[arg].clone(),
&QueryInstruction::PutConstant(_, ref constant, reg) =>
self[reg] = Addr::Con(constant.clone()),
&QueryInstruction::PutList(_, reg) =>
self[reg] = Addr::Lis(self.heap.h),
&QueryInstruction::PutStructure(ref ct, arity, reg) => {
let h = self.heap.h;
self.heap.push(HeapCellValue::NamedStr(arity, ct.name(), ct.spec()));
self[reg] = Addr::Str(h);
},
&QueryInstruction::PutUnsafeValue(n, arg) => {
let e = self.e;
let addr = self.deref(Addr::StackCell(e, n));
if addr.is_protected(e) {
self.registers[arg] = self.store(addr);
} else {
let h = self.heap.h;
self.heap.push(HeapCellValue::Addr(Addr::HeapCell(h)));
self.bind(Ref::HeapCell(h), addr);
self.registers[arg] = self.heap[h].as_addr(h);
}
},
&QueryInstruction::PutValue(norm, arg) =>
self.registers[arg] = self[norm].clone(),
&QueryInstruction::PutVariable(norm, arg) => {
match norm {
RegType::Perm(n) => {
let e = self.e;
self[norm] = Addr::StackCell(e, n);
self.registers[arg] = self[norm].clone();
},
RegType::Temp(_) => {
let h = self.heap.h;
self.heap.push(HeapCellValue::Addr(Addr::HeapCell(h)));
self[norm] = Addr::HeapCell(h);
self.registers[arg] = Addr::HeapCell(h);
}
};
},
&QueryInstruction::SetConstant(ref c) => {
self.heap.push(HeapCellValue::Addr(Addr::Con(c.clone())));
},
&QueryInstruction::SetLocalValue(reg) => {
let addr = self.deref(self[reg].clone());
let h = self.heap.h;
if let Addr::HeapCell(hc) = addr {
if hc < h {
let heap_val = self.heap[hc].clone();
self.heap.push(heap_val);
return;
}
}
self.heap.push(HeapCellValue::Addr(Addr::HeapCell(h)));
self.bind(Ref::HeapCell(h), addr);
},
&QueryInstruction::SetVariable(reg) => {
let h = self.heap.h;
self.heap.push(HeapCellValue::Addr(Addr::HeapCell(h)));
self[reg] = Addr::HeapCell(h);
},
&QueryInstruction::SetValue(reg) => {
let heap_val = self[reg].clone();
self.heap.push(HeapCellValue::Addr(heap_val));
},
&QueryInstruction::SetVoid(n) => {
let h = self.heap.h;
for i in h .. h + n {
self.heap.push(HeapCellValue::Addr(Addr::HeapCell(i)));
}
}
}
}
pub(super) fn handle_internal_call_n(&mut self, arity: usize)
{
let arity = arity + 1;
let pred = self.registers[1].clone();
for i in 2 .. arity {
self.registers[i-1] = self.registers[i].clone();
}
if arity > 1 {
self.registers[arity - 1] = pred;
return;
}
self.fail = true;
}
pub(super) fn set_ball(&mut self) {
let addr = self[temp_v!(1)].clone();
self.ball.boundary = self.heap.h;
let mut duplicator = DuplicateBallTerm::new(self);
duplicator.duplicate_term(addr);
}
pub(super) fn setup_call_n(&mut self, arity: usize) -> Option<PredicateKey>
{
let stub = MachineError::functor_stub(clause_name!("call"), arity + 1);
let addr = self.store(self.deref(self.registers[arity].clone()));
let (name, narity) = match addr {
Addr::Str(a) => {
let result = self.heap[a].clone();
if let HeapCellValue::NamedStr(narity, name, _) = result {
if narity + arity > 63 {
let representation_error =
self.error_form(MachineError::representation_error(RepFlag::MaxArity), stub);
self.throw_exception(representation_error);
return None;
}
for i in (1 .. arity).rev() {
self.registers[i + narity] = self.registers[i].clone();
}
for i in 1 .. narity + 1 {
self.registers[i] = self.heap[a + i].as_addr(a + i);
}
(name, narity)
} else {
self.fail = true;
return None;
}
},
Addr::Con(Constant::Atom(name, _)) => (name, 0),
Addr::HeapCell(_) | Addr::StackCell(_, _) => {
let instantiation_error = self.error_form(MachineError::instantiation_error(), stub);
self.throw_exception(instantiation_error);
return None;
},
_ => {
let type_error = self.error_form(MachineError::type_error(ValidType::Callable, addr), stub);
self.throw_exception(type_error);
return None;
}
};
Some((name, arity + narity - 1))
}
pub(super) fn unwind_stack(&mut self) {
self.b = self.block;
self.or_stack.truncate(self.b);
self.fail = true;
}
fn heap_ball_boundary_diff(&self) -> usize {
if self.ball.boundary > self.heap.h {
self.ball.boundary - self.heap.h
} else {
self.heap.h - self.ball.boundary
}
}
pub(super) fn copy_and_align_ball_to_heap(&mut self) -> usize {
let diff = self.heap_ball_boundary_diff();
for heap_value in self.ball.stub.iter().cloned() {
self.heap.push(match heap_value {
HeapCellValue::Addr(addr) => HeapCellValue::Addr(addr - diff),
_ => heap_value
});
}
diff
}
pub(crate) fn is_cyclic_term(&self, addr: Addr) -> bool {
let mut seen = HashSet::new();
let mut fail = false;
let mut iter = self.pre_order_iter(addr);
loop {
if let Some(addr) = iter.stack().last() {
if !seen.contains(addr) {
seen.insert(addr.clone());
} else {
fail = true;
break;
}
}
if iter.next().is_none() {
break;
}
}
fail
}
// arg(+N, +Term, ?Arg)
pub(super) fn try_arg(&mut self) -> CallResult
{
let stub = MachineError::functor_stub(clause_name!("arg"), 3);
let n = self.store(self.deref(self[temp_v!(1)].clone()));
match n {
Addr::HeapCell(_) | Addr::StackCell(..) => // 8.5.2.3 a)
return Err(self.error_form(MachineError::instantiation_error(), stub)),
Addr::Con(Constant::Number(Number::Integer(n))) => {
if n.is_negative() {
// 8.5.2.3 e)
let n = Addr::Con(Constant::Number(Number::Integer(n)));
let dom_err = MachineError::domain_error(DomainError::NotLessThanZero, n);
return Err(self.error_form(dom_err, stub));
}
let n = match n.to_usize() {
Some(n) => n,
None => {
self.fail = true;
return Ok(());
}
};
let term = self.store(self.deref(self[temp_v!(2)].clone()));
match term {
Addr::HeapCell(_) | Addr::StackCell(..) => // 8.5.2.3 b)
return Err(self.error_form(MachineError::instantiation_error(), stub)),
Addr::Str(o) =>
match self.heap[o].clone() {
HeapCellValue::NamedStr(arity, _, _) if 1 <= n && n <= arity => {
let a3 = self[temp_v!(3)].clone();
let h_a = Addr::HeapCell(o + n);
self.unify(a3, h_a);
},
_ => self.fail = true
},
Addr::Lis(l) =>
if n == 1 || n == 2 {
let a3 = self[temp_v!(3)].clone();
let h_a = Addr::HeapCell(l + n - 1);
self.unify(a3, h_a);
} else {
self.fail = true;
},
_ => // 8.5.2.3 d)
return Err(self.error_form(MachineError::type_error(ValidType::Compound, term),
stub))
}
},
_ => // 8.5.2.3 c)
return Err(self.error_form(MachineError::type_error(ValidType::Integer, n), stub))
}
Ok(())
}
fn compare_numbers(&mut self, cmp: CompareNumberQT, n1: Number, n2: Number) {
let ordering = n1.cmp(&n2);
self.fail = match cmp {
CompareNumberQT::GreaterThan if ordering == Ordering::Greater => false,
CompareNumberQT::GreaterThanOrEqual if ordering != Ordering::Less => false,
CompareNumberQT::LessThan if ordering == Ordering::Less => false,
CompareNumberQT::LessThanOrEqual if ordering != Ordering::Greater => false,
CompareNumberQT::NotEqual if ordering != Ordering::Equal => false,
CompareNumberQT::Equal if ordering == Ordering::Equal => false,
_ => true
};
self.p += 1;
}
pub(super) fn compare_term(&mut self, qt: CompareTermQT) {
let a1 = self[temp_v!(1)].clone();
let a2 = self[temp_v!(2)].clone();
match self.compare_term_test(&a1, &a2) {
Ordering::Greater =>
match qt {
CompareTermQT::GreaterThan | CompareTermQT::GreaterThanOrEqual => return,
_ => self.fail = true
},
Ordering::Equal =>
match qt {
CompareTermQT::GreaterThanOrEqual | CompareTermQT::LessThanOrEqual => return,
_ => self.fail = true
},
Ordering::Less =>
match qt {
CompareTermQT::LessThan | CompareTermQT::LessThanOrEqual => return,
_ => self.fail = true
}
};
}
// returns true on failure.
pub(super) fn eq_test(&self) -> bool
{
let a1 = self[temp_v!(1)].clone();
let a2 = self[temp_v!(2)].clone();
let iter = self.zipped_acyclic_pre_order_iter(a1, a2);
for (v1, v2) in iter {
match (v1, v2) {
(HeapCellValue::NamedStr(ar1, n1, _), HeapCellValue::NamedStr(ar2, n2, _)) =>
if ar1 != ar2 || n1 != n2 {
return true;
},
(HeapCellValue::Addr(Addr::Lis(_)), HeapCellValue::Addr(Addr::Lis(_))) =>
continue,
(HeapCellValue::Addr(a1), HeapCellValue::Addr(a2)) =>
if a1 != a2 {
return true;
},
_ => return true
}
}
false
}
pub(super) fn compare_term_test(&self, a1: &Addr, a2: &Addr) -> Ordering {
let iter = self.zipped_acyclic_pre_order_iter(a1.clone(), a2.clone());
for (v1, v2) in iter {
match (v1, v2) {
(HeapCellValue::Addr(Addr::Lis(_)), HeapCellValue::Addr(Addr::Con(Constant::String(_))))
| (HeapCellValue::Addr(Addr::Con(Constant::String(_))), HeapCellValue::Addr(Addr::Lis(_)))
if self.flags.double_quotes.is_chars() => {},
(HeapCellValue::Addr(Addr::Con(Constant::EmptyList)),
HeapCellValue::Addr(Addr::Con(Constant::String(ref s))))
if self.flags.double_quotes.is_chars() => if s.is_empty() {
return Ordering::Equal;
} else {
return Ordering::Greater;
},
(HeapCellValue::Addr(Addr::Con(Constant::Atom(atom, _))),
HeapCellValue::Addr(Addr::Con(Constant::Char(c)))) =>
return if atom.as_str().chars().count() == 1 {
atom.as_str().chars().next().cmp(&Some(c))
} else {
Ordering::Greater
},
(HeapCellValue::Addr(Addr::Con(Constant::Char(c))),
HeapCellValue::Addr(Addr::Con(Constant::Atom(atom, _)))) =>
return if atom.as_str().chars().count() == 1 {
Some(c).cmp(&atom.as_str().chars().next())
} else {
Ordering::Less
},
(HeapCellValue::Addr(Addr::Con(Constant::String(ref s))),
HeapCellValue::Addr(Addr::Con(Constant::EmptyList)))
if self.flags.double_quotes.is_chars() => if s.is_empty() {
return Ordering::Equal;
} else {
return Ordering::Less;
},
(HeapCellValue::Addr(Addr::HeapCell(hc1)),
HeapCellValue::Addr(Addr::HeapCell(hc2))) =>
if hc1 != hc2 {
return hc1.cmp(&hc2);
},
(HeapCellValue::Addr(Addr::HeapCell(_)), _) =>
return Ordering::Less,
(HeapCellValue::Addr(Addr::StackCell(fr1, sc1)),
HeapCellValue::Addr(Addr::StackCell(fr2, sc2))) =>
if fr1 > fr2 {
return Ordering::Greater;
} else if fr1 < fr2 || sc1 < sc2 {
return Ordering::Less;
} else if sc1 > sc2 {
return Ordering::Greater;
},
(HeapCellValue::Addr(Addr::StackCell(..)),
HeapCellValue::Addr(Addr::HeapCell(_))) =>
return Ordering::Greater,
(HeapCellValue::Addr(Addr::StackCell(..)), _) =>
return Ordering::Less,
(HeapCellValue::Addr(Addr::Con(Constant::Number(..))),
HeapCellValue::Addr(Addr::HeapCell(_))) =>
return Ordering::Greater,
(HeapCellValue::Addr(Addr::Con(Constant::Number(..))),
HeapCellValue::Addr(Addr::StackCell(..))) =>
return Ordering::Greater,
(HeapCellValue::Addr(Addr::Con(Constant::Number(n1))),
HeapCellValue::Addr(Addr::Con(Constant::Number(n2)))) =>
if n1 != n2 {
return n1.cmp(&n2);
},
(HeapCellValue::Addr(Addr::Con(Constant::Number(_))), _) =>
return Ordering::Less,
(HeapCellValue::Addr(Addr::Con(Constant::String(..))),
HeapCellValue::Addr(Addr::HeapCell(_))) =>
return Ordering::Greater,
(HeapCellValue::Addr(Addr::Con(Constant::String(..))),
HeapCellValue::Addr(Addr::StackCell(..))) =>
return Ordering::Greater,
(HeapCellValue::Addr(Addr::Con(Constant::String(_))),
HeapCellValue::Addr(Addr::Con(Constant::Number(_)))) =>
return Ordering::Greater,
(HeapCellValue::Addr(Addr::Con(Constant::String(s1))),
HeapCellValue::Addr(Addr::Con(Constant::String(s2)))) =>
return if s1.is_expandable() {
if s2.is_expandable() {
s1.cmp(&s2)
} else {
Ordering::Greater
}
} else {
if s2.is_expandable() {
Ordering::Less
} else {
s1.cmp(&s2)
}
},
(HeapCellValue::Addr(Addr::Con(Constant::String(_))), _) =>
return Ordering::Less,
(HeapCellValue::Addr(Addr::Con(Constant::Atom(..))),
HeapCellValue::Addr(Addr::HeapCell(_))) =>
return Ordering::Greater,
(HeapCellValue::Addr(Addr::Con(Constant::Atom(..))),
HeapCellValue::Addr(Addr::StackCell(..))) =>
return Ordering::Greater,
(HeapCellValue::Addr(Addr::Con(Constant::Atom(..))),
HeapCellValue::Addr(Addr::Con(Constant::Number(_)))) =>
return Ordering::Greater,
(HeapCellValue::Addr(Addr::Con(Constant::Atom(..))),
HeapCellValue::Addr(Addr::Con(Constant::String(_)))) =>
return Ordering::Greater,
(HeapCellValue::Addr(Addr::Con(Constant::Atom(s1, _))),
HeapCellValue::Addr(Addr::Con(Constant::Atom(s2, _)))) =>
if s1 != s2 {
return s1.cmp(&s2);
},
(HeapCellValue::Addr(Addr::Con(Constant::Atom(..))), _) =>
return Ordering::Less,
(HeapCellValue::NamedStr(ar1, n1, _), HeapCellValue::NamedStr(ar2, n2, _)) =>
if ar1 < ar2 {
return Ordering::Less;
} else if ar1 > ar2 {
return Ordering::Greater;
} else if n1 != n2 {
return n1.cmp(&n2);
},
(HeapCellValue::Addr(Addr::Lis(_)), HeapCellValue::Addr(Addr::Lis(_))) =>
continue,
(HeapCellValue::Addr(Addr::Lis(_)), HeapCellValue::NamedStr(ar, n, _))
| (HeapCellValue::NamedStr(ar, n, _), HeapCellValue::Addr(Addr::Lis(_))) =>
if ar == 2 && n.as_str() == "." {
continue;
} else if ar < 2 {
return Ordering::Greater;
} else if ar > 2 {
return Ordering::Less;
} else {
return n.as_str().cmp(".");
},
(HeapCellValue::NamedStr(..), _) =>
return Ordering::Greater,
(HeapCellValue::Addr(Addr::Lis(_)), _) =>
return Ordering::Greater,
_ => {}
}
};
Ordering::Equal
}
pub(super) fn reset_block(&mut self, addr: Addr) {
match self.store(addr) {
Addr::Con(Constant::Usize(b)) => self.block = b,
_ => self.fail = true
};
}
pub(super) fn execute_inlined(&mut self, inlined: &InlinedClauseType) {
match inlined {
&InlinedClauseType::CompareNumber(cmp, ref at_1, ref at_2) => {
let n1 = try_or_fail!(self, self.get_number(at_1));
let n2 = try_or_fail!(self, self.get_number(at_2));
self.compare_numbers(cmp, n1, n2);
},
&InlinedClauseType::IsAtom(r1) => {
let d = self.store(self.deref(self[r1].clone()));
match d {
Addr::Con(Constant::Atom(..)) | Addr::Con(Constant::Char(_)) => self.p += 1,
_ => self.fail = true
};
},
&InlinedClauseType::IsAtomic(r1) => {
let d = self.store(self.deref(self[r1].clone()));
match d {
Addr::Con(_) => self.p += 1,
_ => self.fail = true
};
},
&InlinedClauseType::IsInteger(r1) => {
let d = self.store(self.deref(self[r1].clone()));
match d {
Addr::Con(Constant::Number(Number::Integer(_))) => self.p += 1,
_ => self.fail = true
};
},
&InlinedClauseType::IsCompound(r1) => {
let d = self.store(self.deref(self[r1].clone()));
match d {
Addr::Str(_) | Addr::Lis(_) => self.p += 1,
_ => self.fail = true
};
},
&InlinedClauseType::IsFloat(r1) => {
let d = self.store(self.deref(self[r1].clone()));
match d {
Addr::Con(Constant::Number(Number::Float(_))) => self.p += 1,
_ => self.fail = true
};
},
&InlinedClauseType::IsRational(r1) => {
let d = self.store(self.deref(self[r1].clone()));
match d {
Addr::Con(Constant::Number(Number::Rational(_))) => self.p += 1,
_ => self.fail = true
};
},
&InlinedClauseType::IsString(r1) => {
let d = self.store(self.deref(self[r1].clone()));
match d {
Addr::Con(Constant::String(_)) => self.p += 1,
_ => self.fail = true
};
},
&InlinedClauseType::IsNonVar(r1) => {
let d = self.store(self.deref(self[r1].clone()));
match d {
Addr::AttrVar(_) | Addr::HeapCell(_) | Addr::StackCell(..) => self.fail = true,
_ => self.p += 1
};
},
&InlinedClauseType::IsVar(r1) => {
let d = self.store(self.deref(self[r1].clone()));
match d {
Addr::AttrVar(_) | Addr::HeapCell(_) | Addr::StackCell(_,_) => self.p += 1,
_ => self.fail = true
};
},
&InlinedClauseType::IsPartialString(r1) => {
let d = self.store(self.deref(self[r1].clone()));
match d {
Addr::Con(Constant::String(ref s)) if s.is_expandable() => self.p += 1,
_ => self.fail = true
};
}
}
}
fn try_functor_unify_components(&mut self, name: Addr, arity: Addr) {
let a2 = self[temp_v!(2)].clone();
let a3 = self[temp_v!(3)].clone();
self.unify(a2, name);
if !self.fail {
self.unify(a3, arity);
}
}
fn try_functor_compound_case(&mut self, name: ClauseName, arity: usize) {
let name = Addr::Con(Constant::Atom(name, None));
let arity = Addr::Con(integer!(arity));
self.try_functor_unify_components(name, arity);
}
pub(super) fn try_functor(&mut self) -> CallResult {
let stub = MachineError::functor_stub(clause_name!("functor"), 3);
let a1 = self.store(self.deref(self[temp_v!(1)].clone()));
match a1.clone() {
Addr::Con(_) =>
self.try_functor_unify_components(a1, Addr::Con(integer!(0))),
Addr::Str(o) =>
match self.heap[o].clone() {
HeapCellValue::NamedStr(arity, name, _) =>
self.try_functor_compound_case(name, arity),
_ => self.fail = true
},
Addr::Lis(_) =>
self.try_functor_compound_case(clause_name!("."), 2),
Addr::AttrVar(..) | Addr::HeapCell(_) | Addr::StackCell(..) => {
let name = self.store(self.deref(self[temp_v!(2)].clone()));
let arity = self.store(self.deref(self[temp_v!(3)].clone()));
if name.is_ref() || arity.is_ref() { // 8.5.1.3 a) & 8.5.1.3 b)
return Err(self.error_form(MachineError::instantiation_error(), stub));
}
if let Addr::Con(Constant::Number(Number::Integer(arity))) = arity {
let arity = match arity.to_isize() {
Some(arity) => arity,
None => {
self.fail = true;
return Ok(());
}
};
if arity > MAX_ARITY as isize {
let rep_err = MachineError::representation_error(RepFlag::MaxArity);
// 8.5.1.3 f)
return Err(self.error_form(rep_err, stub));
} else if arity < 0 {
// 8.5.1.3 g)
let dom_err = MachineError::domain_error(DomainError::NotLessThanZero,
Addr::Con(integer!(arity)));
return Err(self.error_form(dom_err, stub));
}
match name {
Addr::Con(_) if arity == 0 =>
self.unify(a1, name),
Addr::Con(Constant::Atom(name, _)) => {
let f_a = if name.as_str() == "." && arity == 2 {
Addr::Lis(self.heap.h)
} else {
let h = self.heap.h;
self.heap.push(HeapCellValue::NamedStr(arity as usize, name, None));
Addr::Str(h)
};
for _ in 0 .. arity {
let h = self.heap.h;
self.heap.push(HeapCellValue::Addr(Addr::HeapCell(h)));
}
self.unify(a1, f_a);
},
Addr::Con(_) =>
return Err(self.error_form(MachineError::type_error(ValidType::Atom, name),
stub)), // 8.5.1.3 e)
_ =>
return Err(self.error_form(MachineError::type_error(ValidType::Atomic, name),
stub)) // 8.5.1.3 c)
};
} else if !arity.is_ref() {
// 8.5.1.3 d)
return Err(self.error_form(MachineError::type_error(ValidType::Integer, arity), stub));
}
}
};
Ok(())
}
pub(super) fn term_dedup(&self, list: &mut Vec<Addr>) {
let mut result = vec![];
for a2 in list.iter().cloned() {
if let Some(a1) = result.last().cloned() {
if self.compare_term_test(&a1, &a2) == Ordering::Equal {
continue;
}
}
result.push(a2);
}
*list = result;
}
pub(super) fn to_list<Iter: Iterator<Item=Addr>>(&mut self, values: Iter) -> usize {
let head_addr = self.heap.h;
for value in values {
let h = self.heap.h;
self.heap.push(HeapCellValue::Addr(Addr::Lis(h+1)));
self.heap.push(HeapCellValue::Addr(value));
}
self.heap.push(HeapCellValue::Addr(Addr::Con(Constant::EmptyList)));
head_addr
}
pub(super) fn try_from_list(&self, r: RegType, caller: MachineStub)
-> Result<Vec<Addr>, MachineStub>
{
let a1 = self.store(self.deref(self[r].clone()));
match a1.clone() {
Addr::Lis(mut l) => {
let mut result = Vec::new();
result.push(self.heap[l].as_addr(l));
l += 1;
loop {
match self.heap[l].clone() {
HeapCellValue::Addr(addr) =>
match self.store(self.deref(addr)) {
Addr::Lis(hcp) => {
result.push(self.heap[hcp].as_addr(hcp));
l = hcp + 1;
},
Addr::Con(Constant::EmptyList) =>
break,
Addr::HeapCell(_) | Addr::StackCell(..) =>
return Err(self.error_form(MachineError::instantiation_error(), caller)),
_ =>
return Err(self.error_form(MachineError::type_error(ValidType::List, a1),
caller))
},
_ =>
return Err(self.error_form(MachineError::type_error(ValidType::List, a1),
caller))
};
}
Ok(result)
},
Addr::HeapCell(_) | Addr::StackCell(..) =>
Err(self.error_form(MachineError::instantiation_error(), caller)),
Addr::Con(Constant::EmptyList) =>
Ok(vec![]),
_ =>
Err(self.error_form(MachineError::type_error(ValidType::List, a1), caller))
}
}
// see 8.4.4.3 of Draft Technical Corrigendum 2 for an error guide.
pub(super) fn project_onto_key(&self, a: Addr) -> Result<Addr, MachineStub> {
let stub = MachineError::functor_stub(clause_name!("keysort"), 2);
match self.store(self.deref(a)) {
Addr::HeapCell(_) | Addr::StackCell(..) =>
Err(self.error_form(MachineError::instantiation_error(), stub)),
Addr::Str(s) =>
match self.heap[s].clone() {
HeapCellValue::NamedStr(2, ref name, Some(_))
if *name == clause_name!("-") =>
Ok(Addr::HeapCell(s+1)),
_ => Err(self.error_form(MachineError::type_error(ValidType::Pair,
self.heap[s].as_addr(s)),
stub))
},
a => Err(self.error_form(MachineError::type_error(ValidType::Pair, a), stub))
}
}
pub(super) fn duplicate_term(&mut self) {
let old_h = self.heap.h;
let a1 = self[temp_v!(1)].clone();
let a2 = self[temp_v!(2)].clone();
// drop the mutable references contained in gadget
// once the term has been duplicated.
{
let mut gadget = DuplicateTerm::new(self);
gadget.duplicate_term(a1);
}
self.unify(Addr::HeapCell(old_h), a2);
}
// returns true on failure.
pub(super) fn structural_eq_test(&self) -> bool
{
let a1 = self[temp_v!(1)].clone();
let a2 = self[temp_v!(2)].clone();
let mut var_pairs = HashMap::new();
let iter = self.zipped_acyclic_pre_order_iter(a1, a2);
for (v1, v2) in iter {
match (v1, v2) {
(HeapCellValue::Addr(Addr::Lis(l)), HeapCellValue::Addr(Addr::Con(Constant::String(ref s))))
| (HeapCellValue::Addr(Addr::Con(Constant::String(ref s))), HeapCellValue::Addr(Addr::Lis(l)))
if self.flags.double_quotes.is_chars() => if s.is_empty() {
return true;
} else {
if let HeapCellValue::Addr(Addr::Con(constant)) = self.heap[l].clone() {
if let Some(c) = s.head() {
// checks equality on atoms, too.
if constant == Constant::Char(c) {
continue;
}
}
}
return true;
},
(HeapCellValue::Addr(Addr::Con(Constant::String(ref s1))),
HeapCellValue::Addr(Addr::Con(Constant::String(ref s2)))) =>
match s1.head() {
Some(c1) => if let Some(c2) = s2.head() {
if c1 != c2 {
return true;
}
} else {
return true;
},
None => return !s2.is_empty()
},
(HeapCellValue::Addr(Addr::Con(Constant::String(ref s))),
HeapCellValue::Addr(Addr::Con(Constant::EmptyList)))
| (HeapCellValue::Addr(Addr::Con(Constant::EmptyList)),
HeapCellValue::Addr(Addr::Con(Constant::String(ref s))))
if self.flags.double_quotes.is_chars() => if !s.is_empty() {
return true;
},
(HeapCellValue::NamedStr(ar1, n1, _), HeapCellValue::NamedStr(ar2, n2, _)) =>
if ar1 != ar2 || n1 != n2 {
return true;
},
(HeapCellValue::Addr(Addr::Lis(_)), HeapCellValue::Addr(Addr::Lis(_))) =>
continue,
(HeapCellValue::Addr(v1 @ Addr::HeapCell(_)), HeapCellValue::Addr(v2 @ Addr::HeapCell(_)))
| (HeapCellValue::Addr(v1 @ Addr::HeapCell(_)), HeapCellValue::Addr(v2 @ Addr::StackCell(..)))
| (HeapCellValue::Addr(v1 @ Addr::StackCell(..)), HeapCellValue::Addr(v2 @ Addr::StackCell(..)))
| (HeapCellValue::Addr(v1 @ Addr::StackCell(..)), HeapCellValue::Addr(v2 @ Addr::HeapCell(_))) =>
match (var_pairs.get(&v1).cloned(), var_pairs.get(&v2).cloned()) {
(Some(ref v2_p), Some(ref v1_p)) if *v1_p == v1 && *v2_p == v2 =>
continue,
(Some(_), _) | (_, Some(_)) =>
return true,
(None, None) => {
var_pairs.insert(v1.clone(), v2.clone());
var_pairs.insert(v2, v1);
}
},
(HeapCellValue::Addr(a1), HeapCellValue::Addr(a2)) =>
if a1 != a2 {
return true;
},
_ => return true
}
}
false
}
// returns true on failure.
pub(super) fn ground_test(&self) -> bool
{
let a = self.store(self.deref(self[temp_v!(1)].clone()));
for v in self.acyclic_pre_order_iter(a) {
match v {
HeapCellValue::Addr(Addr::HeapCell(..)) =>
return true,
HeapCellValue::Addr(Addr::StackCell(..)) =>
return true,
_ => {}
}
};
false
}
pub(super) fn setup_built_in_call(&mut self, ct: BuiltInClauseType)
{
self.num_of_args = ct.arity();
self.b0 = self.b;
self.p = CodePtr::BuiltInClause(ct, self.p.local());
}
pub(super) fn allocate(&mut self, num_cells: usize) {
let gi = self.next_global_index();
self.p += 1;
if self.e + 1 < self.and_stack.len() {
let and_gi = self.and_stack[self.e].global_index;
let or_gi = self.or_stack.top()
.map(|or_fr| or_fr.global_index)
.unwrap_or(0);
if and_gi > or_gi {
let new_e = self.e + 1;
self.and_stack[new_e].e = self.e;
self.and_stack[new_e].cp = self.cp.clone();
self.and_stack[new_e].global_index = gi;
self.and_stack.resize(new_e, num_cells);
self.e = new_e;
return;
}
}
self.and_stack.push(gi, self.e, self.cp.clone(), num_cells);
self.e = self.and_stack.len() - 1;
}
fn deallocate(&mut self) {
let e = self.e;
self.cp = self.and_stack[e].cp.clone();
self.e = self.and_stack[e].e;
self.p += 1;
}
fn handle_call_clause(&mut self, indices: &mut IndexStore,
call_policy: &mut Box<CallPolicy>,
cut_policy: &mut Box<CutPolicy>,
ct: &ClauseType,
arity: usize,
lco: bool,
use_default_cp: bool)
{
let mut default_call_policy: Box<CallPolicy> = Box::new(DefaultCallPolicy {});
let call_policy = if use_default_cp {
&mut default_call_policy
} else {
call_policy
};
self.last_call = lco;
match ct {
&ClauseType::BuiltIn(ref ct) =>
try_or_fail!(self, call_policy.call_builtin(self, ct, indices)),
&ClauseType::CallN =>
try_or_fail!(self, call_policy.call_n(self, arity, indices)),
&ClauseType::Hook(ref hook) =>
try_or_fail!(self, call_policy.compile_hook(self, hook)),
&ClauseType::Inlined(ref ct) =>
self.execute_inlined(ct),
&ClauseType::Named(ref name, ref idx) | &ClauseType::Op(OpDecl(.., ref name), ref idx) =>
try_or_fail!(self, call_policy.context_call(self, name.clone(), arity, idx.clone(),
indices)),
&ClauseType::System(ref ct) =>
try_or_fail!(self, self.system_call(ct, indices, call_policy, cut_policy))
};
}
pub(super) fn execute_ctrl_instr(&mut self, indices: &mut IndexStore,
call_policy: &mut Box<CallPolicy>,
cut_policy: &mut Box<CutPolicy>,
instr: &ControlInstruction)
{
match instr {
&ControlInstruction::Allocate(num_cells) =>
self.allocate(num_cells),
&ControlInstruction::CallClause(ref ct, arity, _, lco, use_default_cp) =>
self.handle_call_clause(indices, call_policy, cut_policy,
ct, arity, lco, use_default_cp),
&ControlInstruction::Deallocate => self.deallocate(),
&ControlInstruction::JmpBy(arity, offset, _, lco) => {
if !lco {
self.cp.assign_if_local(self.p.clone() + 1);
}
self.num_of_args = arity;
self.b0 = self.b;
self.p += offset;
},
&ControlInstruction::Proceed =>
self.p = CodePtr::Local(self.cp.clone())
};
}
pub(super) fn execute_indexed_choice_instr(&mut self, instr: &IndexedChoiceInstruction,
call_policy: &mut Box<CallPolicy>)
{
match instr {
&IndexedChoiceInstruction::Try(l) => {
let n = self.num_of_args;
let gi = self.next_global_index();
self.or_stack.push(gi,
self.e,
self.cp.clone(),
self.b,
self.p.clone() + 1,
self.tr,
self.pstr_tr,
self.heap.h,
self.b0,
self.num_of_args);
self.b = self.or_stack.len();
let b = self.b - 1;
for i in 1 .. n + 1 {
self.or_stack[b][i] = self.registers[i].clone();
}
self.hb = self.heap.h;
self.p += l;
},
&IndexedChoiceInstruction::Retry(l) =>
try_or_fail!(self, call_policy.retry(self, l)),
&IndexedChoiceInstruction::Trust(l) =>
try_or_fail!(self, call_policy.trust(self, l))
};
}
pub(super) fn execute_choice_instr(&mut self, instr: &ChoiceInstruction,
call_policy: &mut Box<CallPolicy>)
{
match instr {
&ChoiceInstruction::TryMeElse(offset) => {
let n = self.num_of_args;
let gi = self.next_global_index();
self.or_stack.push(gi,
self.e,
self.cp.clone(),
self.b,
self.p.clone() + offset,
self.tr,
self.pstr_tr,
self.heap.h,
self.b0,
self.num_of_args);
self.b = self.or_stack.len();
let b = self.b - 1;
for i in 1 .. n + 1 {
self.or_stack[b][i] = self.registers[i].clone();
}
self.hb = self.heap.h;
self.p += 1;
},
&ChoiceInstruction::DefaultRetryMeElse(offset) => {
let mut call_policy = DefaultCallPolicy {};
try_or_fail!(self, call_policy.retry_me_else(self, offset))
},
&ChoiceInstruction::DefaultTrustMe => {
let mut call_policy = DefaultCallPolicy {};
try_or_fail!(self, call_policy.trust_me(self))
},
&ChoiceInstruction::RetryMeElse(offset) =>
try_or_fail!(self, call_policy.retry_me_else(self, offset)),
&ChoiceInstruction::TrustMe =>
try_or_fail!(self, call_policy.trust_me(self))
}
}
pub(super) fn execute_cut_instr(&mut self, instr: &CutInstruction,
cut_policy: &mut Box<CutPolicy>)
{
match instr {
&CutInstruction::NeckCut => {
let b = self.b;
let b0 = self.b0;
if b > b0 {
self.b = b0;
self.tidy_trail();
self.tidy_pstr_trail();
self.or_stack.truncate(self.b);
}
self.p += 1;
},
&CutInstruction::GetLevel(r) => {
let b0 = self.b0;
self[r] = Addr::Con(Constant::Usize(b0));
self.p += 1;
},
&CutInstruction::GetLevelAndUnify(r) => {
let b0 = self[perm_v!(1)].clone();
let a = self[r].clone();
self.unify(a, b0);
self.p += 1;
},
&CutInstruction::Cut(r) => if !cut_policy.cut(self, r) {
self.p += 1;
}
}
}
pub(super) fn reset(&mut self) {
self.hb = 0;
self.e = 0;
self.b = 0;
self.b0 = 0;
self.s = 0;
self.tr = 0;
self.pstr_tr = 0;
self.p = CodePtr::default();
self.cp = LocalCodePtr::default();
self.special_form_cp = CodePtr::default();
self.num_of_args = 0;
self.fail = false;
self.trail.clear();
self.pstr_trail.clear();
self.heap.clear();
self.mode = MachineMode::Write;
self.and_stack.clear();
self.or_stack.clear();
self.registers = vec![Addr::HeapCell(0); 64];
self.block = 0;
self.ball.reset();
}
}
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