Files
scryer-prolog/src/prolog/machine/machine_state.rs

1802 lines
56 KiB
Rust

use prolog_parser::ast::*;
use prolog_parser::tabled_rc::*;
use crate::prolog::clause_types::*;
use crate::prolog::forms::*;
use crate::prolog::heap_print::*;
use crate::prolog::machine::attributed_variables::*;
use crate::prolog::machine::copier::*;
use crate::prolog::machine::heap::*;
use crate::prolog::machine::machine_errors::*;
use crate::prolog::machine::machine_indices::*;
use crate::prolog::machine::modules::*;
use crate::prolog::machine::stack::*;
use crate::prolog::machine::streams::*;
use crate::prolog::rug::Integer;
use downcast::Any;
use indexmap::{IndexMap, IndexSet};
use std::cmp::Ordering;
use std::convert::TryFrom;
use std::fmt;
use std::io::Write;
use std::mem;
use std::ops::{Index, IndexMut};
#[derive(Debug)]
pub(crate) struct HeapPStrIter<'a> {
focus: Addr,
machine_st: &'a MachineState,
seen: IndexSet<Addr>,
}
impl<'a> HeapPStrIter<'a> {
#[inline]
fn new(machine_st: &'a MachineState, focus: Addr) -> Self {
HeapPStrIter {
focus,
machine_st,
seen: IndexSet::new(),
}
}
#[inline]
pub(crate)
fn focus(&self) -> Addr {
self.machine_st.store(self.machine_st.deref(self.focus))
}
#[inline]
pub(crate)
fn to_string(&mut self) -> String {
let mut buf = String::new();
while let Some(iteratee) = self.next() {
match iteratee {
PStrIteratee::Char(c) => {
buf.push(c);
}
PStrIteratee::PStrSegment(h, n) => {
match &self.machine_st.heap[h] {
HeapCellValue::PartialString(ref pstr, _) => {
buf += pstr.as_str_from(n);
}
_ => {
unreachable!()
}
}
}
}
}
buf
}
}
#[derive(Debug, Clone, Copy)]
pub(crate) enum PStrIteratee {
Char(char),
PStrSegment(usize, usize),
}
impl<'a> Iterator for HeapPStrIter<'a> {
type Item = PStrIteratee;
fn next(&mut self) -> Option<Self::Item> {
let addr = self.machine_st.store(self.machine_st.deref(self.focus));
if !self.seen.contains(&addr) {
self.seen.insert(addr);
} else {
return None;
}
match addr {
Addr::PStrLocation(h, n) => {
if let &HeapCellValue::PartialString(_, has_tail) = &self.machine_st.heap[h] {
self.focus = if has_tail {
Addr::HeapCell(h + 1)
} else {
Addr::EmptyList
};
return Some(PStrIteratee::PStrSegment(h, n));
} else {
unreachable!()
}
}
Addr::Lis(l) => {
let addr = self.machine_st.store(self.machine_st.deref(Addr::HeapCell(l)));
let opt_c = match addr {
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())
} else {
None
}
} else {
unreachable!()
}
}
Addr::Char(c) => {
Some(c)
}
_ => {
None
}
};
if let Some(c) = opt_c {
self.focus = Addr::HeapCell(l + 1);
return Some(PStrIteratee::Char(c));
} else {
return None;
}
}
Addr::EmptyList => {
self.focus = Addr::EmptyList;
return None;
}
_ => {
return None;
}
}
}
}
#[inline]
pub(super)
fn compare_pstr_prefixes<'a>(
i1: &mut HeapPStrIter<'a>,
i2: &mut HeapPStrIter<'a>,
) -> Option<Ordering> {
let mut r1 = i1.next();
let mut r2 = i2.next();
loop {
if let Some(r1i) = r1 {
if let Some(r2i) = r2 {
match (r1i, r2i) {
(PStrIteratee::Char(c1), PStrIteratee::Char(c2)) => {
if c1 != c2 {
return c1.partial_cmp(&c2);
}
}
(PStrIteratee::Char(c1), PStrIteratee::PStrSegment(h, n)) => {
if let &HeapCellValue::PartialString(ref pstr, _) = &i2.machine_st.heap[h] {
if let Some(c2) = pstr.as_str_from(n).chars().next() {
if c1 != c2 {
return c1.partial_cmp(&c2);
} else {
r1 = i1.next();
r2 = Some(PStrIteratee::PStrSegment(h, n + c2.len_utf8()));
continue;
}
} else {
r2 = i2.next();
continue;
}
} else {
unreachable!()
}
}
(PStrIteratee::PStrSegment(h, n), PStrIteratee::Char(c2)) => {
if let &HeapCellValue::PartialString(ref pstr, _) = &i1.machine_st.heap[h] {
if let Some(c1) = pstr.as_str_from(n).chars().next() {
if c1 != c2 {
return c2.partial_cmp(&c1);
} else {
r1 = i1.next();
r2 = Some(PStrIteratee::PStrSegment(h, n + c1.len_utf8()));
continue;
}
} else {
r1 = i1.next();
continue;
}
} else {
unreachable!()
}
}
(PStrIteratee::PStrSegment(h1, n1), PStrIteratee::PStrSegment(h2, n2)) => {
match (&i1.machine_st.heap[h1], &i2.machine_st.heap[h2]) {
(
&HeapCellValue::PartialString(ref pstr1, _),
&HeapCellValue::PartialString(ref pstr2, _),
) => {
let str1 = pstr1.as_str_from(n1);
let str2 = pstr2.as_str_from(n2);
if str1.starts_with(str2) {
r1 = Some(PStrIteratee::PStrSegment(h1, n1 + str2.len()));
r2 = i2.next();
continue;
} else if str2.starts_with(str1) {
r1 = i1.next();
r2 = Some(PStrIteratee::PStrSegment(h2, n2 + str1.len()));
continue;
} else {
return str1.partial_cmp(str2);
}
}
_ => {
unreachable!()
}
}
}
}
r1 = i1.next();
r2 = i2.next();
continue;
}
}
return match (i1.focus(), i2.focus()) {
(Addr::EmptyList, Addr::EmptyList) => {
Some(Ordering::Equal)
}
(Addr::EmptyList, _) => {
Some(Ordering::Less)
}
(_, Addr::EmptyList) => {
Some(Ordering::Greater)
}
_ => {
None
}
};
}
}
#[inline]
pub(super)
fn compare_pstr_to_string<'a>(
heap_pstr_iter: &mut HeapPStrIter<'a>,
s: &String,
) -> Option<usize> {
let mut s_offset = 0;
while let Some(iteratee) = heap_pstr_iter.next() {
match iteratee {
PStrIteratee::Char(c1) => {
if let Some(c2) = s[s_offset ..].chars().next() {
if c1 != c2 {
return None;
} else {
s_offset += c1.len_utf8();
}
} else {
return Some(s_offset);
}
}
PStrIteratee::PStrSegment(h, n) => {
match heap_pstr_iter.machine_st.heap[h] {
HeapCellValue::PartialString(ref pstr, _) => {
let t = pstr.as_str_from(n);
if s[s_offset ..].starts_with(t) {
s_offset += t.len();
} else if t.starts_with(&s[s_offset ..]) {
heap_pstr_iter.focus =
Addr::PStrLocation(h, n + s[s_offset ..].len());
s_offset += s[s_offset ..].len();
return Some(s_offset);
} else {
return None;
}
}
_ => {
unreachable!()
}
}
}
}
if s[s_offset ..].is_empty() {
return Some(s_offset);
}
}
Some(s_offset)
}
#[derive(Debug)]
pub struct Ball {
pub(super) boundary: usize,
pub(super) stub: Heap,
}
impl Ball {
pub(super)
fn new() -> Self {
Ball {
boundary: 0,
stub: Heap::new(),
}
}
pub(super)
fn reset(&mut self) {
self.boundary = 0;
self.stub.clear();
}
pub(super)
fn take(&mut self) -> Ball {
let boundary = self.boundary;
self.boundary = 0;
Ball {
boundary,
stub: self.stub.take(),
}
}
pub(super)
fn copy_and_align(&self, h: usize) -> Heap {
let diff = self.boundary as i64 - h as i64;
let mut stub = Heap::new();
for heap_value in self.stub.iter_from(0) {
stub.push(match heap_value {
&HeapCellValue::Addr(addr) => {
HeapCellValue::Addr(addr - diff)
}
heap_value => {
heap_value.context_free_clone()
}
});
}
stub
}
}
#[derive(Debug)]
pub(super) struct CopyTerm<'a> {
state: &'a mut MachineState,
}
impl<'a> CopyTerm<'a> {
pub(super) fn new(state: &'a mut MachineState) -> Self {
CopyTerm { state: state }
}
}
impl<'a> Index<usize> for CopyTerm<'a> {
type Output = HeapCellValue;
fn index(&self, index: usize) -> &Self::Output {
&self.state.heap[index]
}
}
impl<'a> IndexMut<usize> for CopyTerm<'a> {
fn index_mut(&mut self, index: usize) -> &mut Self::Output {
&mut self.state.heap[index]
}
}
// the ordinary, heap term copier, used by duplicate_term.
impl<'a> CopierTarget for CopyTerm<'a> {
fn threshold(&self) -> usize {
self.state.heap.h()
}
fn push(&mut self, hcv: HeapCellValue) {
self.state.heap.push(hcv);
}
fn store(&self, a: Addr) -> Addr {
self.state.store(a)
}
fn deref(&self, a: Addr) -> Addr {
self.state.deref(a)
}
fn stack(&mut self) -> &mut Stack {
&mut self.state.stack
}
}
#[derive(Debug)]
pub(super) struct CopyBallTerm<'a> {
stack: &'a mut Stack,
heap: &'a mut Heap,
heap_boundary: usize,
stub: &'a mut Heap,
}
impl<'a> CopyBallTerm<'a> {
pub(super) fn new(
stack: &'a mut Stack,
heap: &'a mut Heap,
stub: &'a mut Heap,
) -> Self {
let hb = heap.h();
CopyBallTerm {
stack,
heap,
heap_boundary: hb,
stub,
}
}
}
impl<'a> Index<usize> for CopyBallTerm<'a> {
type Output = HeapCellValue;
fn index(&self, index: usize) -> &Self::Output {
if index < self.heap_boundary {
&self.heap[index]
} else {
let index = index - self.heap_boundary;
&self.stub[index]
}
}
}
impl<'a> IndexMut<usize> for CopyBallTerm<'a> {
fn index_mut(&mut self, index: usize) -> &mut Self::Output {
if index < self.heap_boundary {
&mut self.heap[index]
} else {
let index = index - self.heap_boundary;
&mut self.stub[index]
}
}
}
// the ordinary, heap term copier, used by duplicate_term.
impl<'a> CopierTarget for CopyBallTerm<'a> {
fn threshold(&self) -> usize {
self.heap_boundary + self.stub.h()
}
fn push(&mut self, value: HeapCellValue) {
self.stub.push(value);
}
fn store(&self, addr: Addr) -> Addr {
match addr {
Addr::HeapCell(h) | Addr::AttrVar(h) if h < self.heap_boundary => {
self.heap[h].as_addr(h)
}
Addr::HeapCell(h) | Addr::AttrVar(h) => {
let index = h - self.heap_boundary;
self.stub[index].as_addr(h)
}
Addr::StackCell(fr, sc) => {
self.stack.index_and_frame(fr)[sc]
}
addr => {
addr
}
}
}
fn deref(&self, mut addr: Addr) -> Addr {
loop {
let value = self.store(addr);
if value.is_ref() && value != addr {
addr = value;
continue;
}
return addr;
}
}
fn stack(&mut self) -> &mut Stack {
self.stack
}
}
impl Index<RegType> for MachineState {
type Output = Addr;
fn index(&self, reg: RegType) -> &Self::Output {
match reg {
RegType::Temp(temp) => &self.registers[temp],
RegType::Perm(perm) => {
let e = self.e;
&self.stack.index_and_frame(e)[perm]
}
}
}
}
impl IndexMut<RegType> for MachineState {
fn index_mut(&mut self, reg: RegType) -> &mut Self::Output {
match reg {
RegType::Temp(temp) => {
&mut self.registers[temp]
}
RegType::Perm(perm) => {
let e = self.e;
&mut self.stack.index_and_frame_mut(e)[perm]
}
}
}
}
pub type Registers = Vec<Addr>;
#[derive(Debug, Clone, Copy)]
pub(super) enum MachineMode {
Read,
Write,
}
#[derive(Debug, Clone)]
pub(super) enum HeapPtr {
HeapCell(usize),
PStrChar(usize, usize),
PStrLocation(usize, usize),
}
impl HeapPtr {
#[inline]
pub(super)
fn read(&self, heap: &Heap) -> Addr {
match self {
&HeapPtr::HeapCell(h) => {
Addr::HeapCell(h)
}
&HeapPtr::PStrChar(h, n) => {
if let &HeapCellValue::PartialString(ref pstr, has_tail) = &heap[h] {
if let Some(c) = pstr.range_from(n ..).next() {
Addr::Char(c)
} else if has_tail {
Addr::HeapCell(h + 1)
} else {
Addr::EmptyList
}
} else {
unreachable!()
}
}
&HeapPtr::PStrLocation(h, n) => {
Addr::PStrLocation(h, n)
}
}
}
}
impl Default for HeapPtr {
fn default() -> Self {
HeapPtr::HeapCell(0)
}
}
#[derive(Debug)]
pub struct MachineState {
pub(super) s: HeapPtr,
pub(super) p: CodePtr,
pub(super) b: usize,
pub(super) b0: usize,
pub(super) e: usize,
pub(super) num_of_args: usize,
pub(super) cp: LocalCodePtr,
pub(super) attr_var_init: AttrVarInitializer,
pub(super) fail: bool,
pub(crate) heap: Heap,
pub(super) mode: MachineMode,
pub(crate) stack: Stack,
pub(super) registers: Registers,
pub(super) trail: Vec<TrailRef>,
pub(super) tr: usize,
pub(super) hb: usize,
pub(super) block: usize, // an offset into the OR stack.
pub(super) ball: Ball,
pub(super) lifted_heap: Heap,
pub(super) interms: Vec<Number>, // intermediate numbers.
pub(super) last_call: bool,
pub(crate) heap_locs: HeapVarDict,
pub(crate) flags: MachineFlags,
pub(crate) at_end_of_expansion: bool
}
impl MachineState {
pub(crate)
fn read_term(
&mut self,
stream: Stream,
indices: &mut IndexStore,
) -> CallResult {
let mut orig_stream = stream.clone();
let mut stream = self.open_parsing_stream(stream, "read_term", 3)?;
loop {
match self.read(
&mut stream,
indices.atom_tbl.clone(),
&indices.op_dir,
) {
Ok(term_write_result) => {
let term = self[temp_v!(2)];
self.unify(Addr::HeapCell(term_write_result.heap_loc), term);
if self.fail {
return Ok(());
}
let mut list_of_var_eqs = vec![];
for (var, binding) in term_write_result.var_dict.into_iter() {
let var_atom = clause_name!(var.to_string(), indices.atom_tbl);
let h = self.heap.h();
let spec = fetch_atom_op_spec(clause_name!("="), None, &indices.op_dir);
self.heap.push(HeapCellValue::NamedStr(2, clause_name!("="), spec));
self.heap.push(HeapCellValue::Atom(var_atom, None));
self.heap.push(HeapCellValue::Addr(binding));
list_of_var_eqs.push(Addr::Str(h));
}
let mut var_set: IndexMap<Ref, bool> = IndexMap::new();
for addr in self.acyclic_pre_order_iter(term) {
if let Some(var) = addr.as_var() {
if !var_set.contains_key(&var) {
var_set.insert(var, true);
} else {
var_set.insert(var, false);
}
}
}
let mut var_list = vec![];
let mut singleton_var_list = vec![];
for addr in self.acyclic_pre_order_iter(term) {
if let Some(var) = addr.as_var() {
if var_set.get(&var) == Some(&true) {
singleton_var_list.push(var.as_addr());
}
var_list.push(var.as_addr());
}
}
let singleton_addr = self[temp_v!(3)];
let singletons_offset =
Addr::HeapCell(self.heap.to_list(singleton_var_list.into_iter()));
self.unify(singletons_offset, singleton_addr);
if self.fail {
return Ok(());
}
let vars_addr = self[temp_v!(4)];
let vars_offset =
Addr::HeapCell(self.heap.to_list(var_list.into_iter()));
self.unify(vars_offset, vars_addr);
if self.fail {
return Ok(());
}
let var_names_addr = self[temp_v!(5)];
let var_names_offset =
Addr::HeapCell(self.heap.to_list(list_of_var_eqs.into_iter()));
return Ok(self.unify(var_names_offset, var_names_addr));
}
Err(err) => {
if let ParserError::UnexpectedEOF = err {
self.eof_action(
self[temp_v!(2)],
&mut orig_stream,
clause_name!("read_term"),
3
)?;
if orig_stream.options.eof_action == EOFAction::Reset {
if self.fail == false {
continue;
} else {
return Ok(());
}
}
}
return Ok(());
}
}
}
}
pub(crate)
fn write_term<'a>(
&'a self,
op_dir: &'a OpDir,
) -> Result<Option<HCPrinter<'a, PrinterOutputter>>, MachineStub>
{
let ignore_ops = self.store(self.deref(self[temp_v!(3)]));
let numbervars = self.store(self.deref(self[temp_v!(4)]));
let quoted = self.store(self.deref(self[temp_v!(5)]));
let max_depth = self.store(self.deref(self[temp_v!(7)]));
let mut printer = HCPrinter::new(&self, op_dir, PrinterOutputter::new());
if let &Addr::Con(h) = &ignore_ops {
if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
printer.ignore_ops = name.as_str() == "true";
} else {
unreachable!()
}
}
if let &Addr::Con(h) = &numbervars {
if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
printer.numbervars = name.as_str() == "true";
} else {
unreachable!()
}
}
if let &Addr::Con(h) = &quoted {
if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
printer.quoted = name.as_str() == "true";
} else {
unreachable!()
}
}
match Number::try_from((max_depth, &self.heap)) {
Ok(Number::Fixnum(n)) => {
if let Ok(n) = usize::try_from(n) {
printer.max_depth = n;
} else {
return Ok(None);
}
}
Ok(Number::Integer(n)) => {
if let Some(n) = n.to_usize() {
printer.max_depth = n;
} else {
return Ok(None);
}
}
_ => {
unreachable!();
}
}
let stub = MachineError::functor_stub(clause_name!("write_term"), 2);
match self.try_from_list(temp_v!(6), stub) {
Ok(addrs) => {
let mut var_names: IndexMap<Addr, String> = IndexMap::new();
for addr in addrs {
match addr {
Addr::Str(s) => match &self.heap[s] {
&HeapCellValue::NamedStr(2, ref name, _)
if name.as_str() == "=" =>
{
let atom = self.heap[s + 1].as_addr(s + 1);
let var = self.heap[s + 2].as_addr(s + 2);
let atom = match self.store(self.deref(atom)) {
Addr::Con(h) => {
if let HeapCellValue::Atom(ref atom, _) = &self.heap[h] {
atom.to_string()
} else {
unreachable!()
}
}
Addr::Char(c) => c.to_string(),
_ => unreachable!(),
};
let var = self.store(self.deref(var));
if var_names.contains_key(&var) {
continue;
}
var_names.insert(var, atom);
}
_ => {
}
},
_ => {
}
}
}
printer.var_names = var_names;
}
Err(err) => {
return Err(err);
}
}
Ok(Some(printer))
}
#[inline]
pub(crate)
fn heap_pstr_iter<'a>(&'a self, focus: Addr) -> HeapPStrIter<'a> {
HeapPStrIter::new(self, focus)
}
pub(super)
fn try_char_list(&self, addrs: Vec<Addr>) -> Result<String, MachineError> {
let mut chars = String::new();
let mut iter = addrs.iter();
while let Some(addr) = iter.next() {
let addr = self.store(self.deref(*addr));
match addr {
Addr::Char(c) => {
chars.push(c);
continue;
}
Addr::Con(h) => {
if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
if name.is_char() {
chars += name.as_str();
continue;
}
}
}
_ => {
}
};
let h = self.heap.h();
return Err(
MachineError::type_error(h, ValidType::Character, addr)
);
}
Ok(chars)
}
pub(super)
fn call_at_index(&mut self, arity: usize, p: LocalCodePtr) {
self.cp.assign_if_local(self.p.clone() + 1);
self.num_of_args = arity;
self.b0 = self.b;
self.p = CodePtr::Local(p);
}
pub(super)
fn execute_at_index(&mut self, arity: usize, p: LocalCodePtr) {
self.num_of_args = arity;
self.b0 = self.b;
self.p = CodePtr::Local(p);
}
pub(super)
fn module_lookup(
&mut self,
indices: &IndexStore,
key: PredicateKey,
module_name: ClauseName,
last_call: bool,
) -> CallResult {
let (name, arity) = key;
if let Some(ref idx) = indices.get_code_index((name.clone(), arity), module_name.clone()) {
match idx.0.borrow().0 {
IndexPtr::Index(compiled_tl_index) => {
if last_call {
self.execute_at_index(arity, dir_entry!(compiled_tl_index));
} else {
self.call_at_index(arity, dir_entry!(compiled_tl_index));
}
return Ok(());
}
IndexPtr::DynamicUndefined => {
self.fail = true;
return Ok(());
}
IndexPtr::UserTermExpansion => {
if last_call {
self.execute_at_index(arity, LocalCodePtr::UserTermExpansion(0));
} else {
self.call_at_index(arity, LocalCodePtr::UserTermExpansion(0));
}
return Ok(());
}
IndexPtr::UserGoalExpansion => {
if last_call {
self.execute_at_index(arity, LocalCodePtr::UserGoalExpansion(0));
} else {
self.call_at_index(arity, LocalCodePtr::UserGoalExpansion(0));
}
return Ok(());
}
IndexPtr::InSituDirEntry(p) => {
if last_call {
self.execute_at_index(arity, LocalCodePtr::InSituDirEntry(p));
} else {
self.call_at_index(arity, LocalCodePtr::InSituDirEntry(p));
}
return Ok(());
}
_ => {}
}
}
let h = self.heap.h();
let stub = MachineError::functor_stub(name.clone(), arity);
let err = MachineError::module_resolution_error(h, module_name, name, arity);
return Err(self.error_form(err, stub));
}
}
fn try_in_situ_lookup(name: ClauseName, arity: usize, indices: &IndexStore) -> Option<LocalCodePtr>
{
match indices.in_situ_code_dir.get(&(name.clone(), arity)) {
Some(p) => Some(LocalCodePtr::InSituDirEntry(*p)),
None =>
match indices.code_dir.get(&(name, arity)) {
Some(ref idx) => {
if let IndexPtr::Index(p) = idx.0.borrow().0 {
Some(LocalCodePtr::DirEntry(p))
} else {
None
}
}
_ => None,
},
}
}
fn try_in_situ(
machine_st: &mut MachineState,
name: ClauseName,
arity: usize,
indices: &IndexStore,
last_call: bool,
) -> CallResult {
if let Some(p) = try_in_situ_lookup(name.clone(), arity, indices) {
if last_call {
machine_st.execute_at_index(arity, p);
} else {
machine_st.call_at_index(arity, p);
}
machine_st.p = CodePtr::Local(p);
Ok(())
} else {
let stub = MachineError::functor_stub(name.clone(), arity);
let h = machine_st.heap.h();
let key = ExistenceError::Procedure(name, arity);
Err(machine_st.error_form(MachineError::existence_error(h, key), stub))
}
}
pub(crate) type CallResult = Result<(), Vec<HeapCellValue>>;
pub(crate) trait CallPolicy: Any + fmt::Debug {
fn retry_me_else(&mut self, machine_st: &mut MachineState, offset: usize) -> CallResult {
let b = machine_st.b;
let n = machine_st.stack.index_or_frame(b).prelude.univ_prelude.num_cells;
for i in 1 .. n + 1 {
machine_st.registers[i] = machine_st.stack.index_or_frame(b)[i-1];
}
machine_st.num_of_args = n;
machine_st.e = machine_st.stack.index_or_frame(b).prelude.e;
machine_st.cp = machine_st.stack.index_or_frame(b).prelude.cp;
machine_st.stack.index_or_frame_mut(b).prelude.bp = machine_st.p.local() + offset;
let old_tr = machine_st.stack.index_or_frame(b).prelude.tr;
let curr_tr = machine_st.tr;
machine_st.unwind_trail(old_tr, curr_tr);
machine_st.tr = machine_st.stack.index_or_frame(b).prelude.tr;
machine_st.trail.truncate(machine_st.tr);
machine_st.heap.truncate(machine_st.stack.index_or_frame(b).prelude.h);
let attr_var_init_queue_b =
machine_st.stack.index_or_frame(b).prelude.attr_var_init_queue_b;
let attr_var_init_bindings_b =
machine_st.stack.index_or_frame(b).prelude.attr_var_init_bindings_b;
machine_st.attr_var_init.backtrack(
attr_var_init_queue_b,
attr_var_init_bindings_b,
);
machine_st.hb = machine_st.heap.h();
machine_st.p += 1;
Ok(())
}
fn retry(&mut self, machine_st: &mut MachineState, offset: usize) -> CallResult {
let b = machine_st.b;
let n = machine_st.stack.index_or_frame(b).prelude.univ_prelude.num_cells;
for i in 1 .. n + 1 {
machine_st.registers[i] = machine_st.stack.index_or_frame(b)[i-1];
}
machine_st.num_of_args = n;
machine_st.e = machine_st.stack.index_or_frame(b).prelude.e;
machine_st.cp = machine_st.stack.index_or_frame(b).prelude.cp;
machine_st.stack.index_or_frame_mut(b).prelude.bp = machine_st.p.local() + 1;
let old_tr = machine_st.stack.index_or_frame(b).prelude.tr;
let curr_tr = machine_st.tr;
machine_st.unwind_trail(old_tr, curr_tr);
machine_st.tr = machine_st.stack.index_or_frame(b).prelude.tr;
machine_st.trail.truncate(machine_st.tr);
machine_st.heap.truncate(machine_st.stack.index_or_frame(b).prelude.h);
let attr_var_init_queue_b =
machine_st.stack.index_or_frame(b).prelude.attr_var_init_queue_b;
let attr_var_init_bindings_b =
machine_st.stack.index_or_frame(b).prelude.attr_var_init_bindings_b;
machine_st.attr_var_init.backtrack(attr_var_init_queue_b, attr_var_init_bindings_b);
machine_st.hb = machine_st.heap.h();
machine_st.p += offset;
Ok(())
}
fn trust(&mut self, machine_st: &mut MachineState, offset: usize) -> CallResult {
let b = machine_st.b;
let n = machine_st.stack.index_or_frame(b).prelude.univ_prelude.num_cells;
for i in 1 .. n + 1 {
machine_st.registers[i] = machine_st.stack.index_or_frame(b)[i-1];
}
machine_st.num_of_args = n;
machine_st.e = machine_st.stack.index_or_frame(b).prelude.e;
machine_st.cp = machine_st.stack.index_or_frame(b).prelude.cp;
let old_tr = machine_st.stack.index_or_frame(b).prelude.tr;
let curr_tr = machine_st.tr;
machine_st.unwind_trail(old_tr, curr_tr);
machine_st.tr = machine_st.stack.index_or_frame(b).prelude.tr;
machine_st.trail.truncate(machine_st.tr);
machine_st.heap.truncate(machine_st.stack.index_or_frame(b).prelude.h);
let attr_var_init_queue_b =
machine_st.stack.index_or_frame(b).prelude.attr_var_init_queue_b;
let attr_var_init_bindings_b =
machine_st.stack.index_or_frame(b).prelude.attr_var_init_bindings_b;
machine_st.attr_var_init.backtrack(
attr_var_init_queue_b,
attr_var_init_bindings_b,
);
machine_st.b = machine_st.stack.index_or_frame(b).prelude.b;
machine_st.stack.truncate(b);
machine_st.hb = machine_st.heap.h();
machine_st.p += offset;
Ok(())
}
fn trust_me(&mut self, machine_st: &mut MachineState) -> CallResult {
let b = machine_st.b;
let n = machine_st.stack.index_or_frame(b).prelude.univ_prelude.num_cells;
for i in 1 .. n + 1 {
machine_st.registers[i] = machine_st.stack.index_or_frame(b)[i-1];
}
machine_st.num_of_args = n;
machine_st.e = machine_st.stack.index_or_frame(b).prelude.e;
machine_st.cp = machine_st.stack.index_or_frame(b).prelude.cp;
let old_tr = machine_st.stack.index_or_frame(b).prelude.tr;
let curr_tr = machine_st.tr;
machine_st.unwind_trail(old_tr, curr_tr);
machine_st.tr = machine_st.stack.index_or_frame(b).prelude.tr;
machine_st.trail.truncate(machine_st.tr);
machine_st.heap.truncate(machine_st.stack.index_or_frame(b).prelude.h);
let attr_var_init_queue_b =
machine_st.stack.index_or_frame(b).prelude.attr_var_init_queue_b;
let attr_var_init_bindings_b =
machine_st.stack.index_or_frame(b).prelude.attr_var_init_bindings_b;
machine_st.attr_var_init.backtrack(
attr_var_init_queue_b,
attr_var_init_bindings_b,
);
machine_st.b = machine_st.stack.index_or_frame(b).prelude.b;
machine_st.stack.truncate(b);
machine_st.hb = machine_st.heap.h();
machine_st.p += 1;
Ok(())
}
fn context_call(
&mut self,
machine_st: &mut MachineState,
name: ClauseName,
arity: usize,
idx: CodeIndex,
indices: &mut IndexStore,
) -> CallResult {
if machine_st.last_call {
self.try_execute(machine_st, name, arity, idx, indices)
} else {
self.try_call(machine_st, name, arity, idx, indices)
}
}
fn try_call(
&mut self,
machine_st: &mut MachineState,
name: ClauseName,
arity: usize,
idx: CodeIndex,
indices: &IndexStore,
) -> CallResult {
match idx.0.borrow().0 {
IndexPtr::DynamicUndefined => {
machine_st.fail = true;
}
IndexPtr::Undefined => {
return try_in_situ(machine_st, name, arity, indices, false);
}
IndexPtr::Index(compiled_tl_index) => {
machine_st.call_at_index(arity, LocalCodePtr::DirEntry(compiled_tl_index))
}
IndexPtr::UserTermExpansion => {
machine_st.call_at_index(arity, LocalCodePtr::UserTermExpansion(0));
}
IndexPtr::UserGoalExpansion => {
machine_st.call_at_index(arity, LocalCodePtr::UserGoalExpansion(0));
}
IndexPtr::InSituDirEntry(p) => {
machine_st.call_at_index(arity, LocalCodePtr::InSituDirEntry(p));
}
}
Ok(())
}
fn try_execute(
&mut self,
machine_st: &mut MachineState,
name: ClauseName,
arity: usize,
idx: CodeIndex,
indices: &IndexStore,
) -> CallResult {
match idx.0.borrow().0 {
IndexPtr::DynamicUndefined =>
machine_st.fail = true,
IndexPtr::Undefined =>
return try_in_situ(machine_st, name, arity, indices, true),
IndexPtr::Index(compiled_tl_index) => {
machine_st.execute_at_index(arity, dir_entry!(compiled_tl_index))
}
IndexPtr::UserTermExpansion => {
machine_st.execute_at_index(arity, LocalCodePtr::UserTermExpansion(0));
}
IndexPtr::UserGoalExpansion => {
machine_st.execute_at_index(arity, LocalCodePtr::UserGoalExpansion(0));
}
IndexPtr::InSituDirEntry(p) => {
machine_st.execute_at_index(arity, LocalCodePtr::InSituDirEntry(p));
}
}
Ok(())
}
fn call_builtin(
&mut self,
machine_st: &mut MachineState,
ct: &BuiltInClauseType,
indices: &mut IndexStore,
current_input_stream: &mut Stream,
current_output_stream: &mut Stream,
) -> CallResult {
match ct {
&BuiltInClauseType::AcyclicTerm => {
let addr = machine_st[temp_v!(1)];
machine_st.fail = machine_st.is_cyclic_term(addr);
return_from_clause!(machine_st.last_call, machine_st)
}
&BuiltInClauseType::Arg => {
machine_st.try_arg()?;
return_from_clause!(machine_st.last_call, machine_st)
}
&BuiltInClauseType::Compare => {
let a1 = machine_st.store(machine_st.deref(machine_st[temp_v!(1)]));
let a2 = machine_st[temp_v!(2)];
let a3 = machine_st[temp_v!(3)];
match a1 {
Addr::Con(h) if machine_st.heap.atom_at(h) => {
if let HeapCellValue::Atom(ref atom, _) = &machine_st.heap[h] {
match atom.as_str() {
">" | "<" | "=" => {
}
_ => {
let stub =
MachineError::functor_stub(clause_name!("compare"), 3);
let err = MachineError::domain_error(DomainErrorType::Order, a1);
return Err(machine_st.error_form(err, stub));
}
}
} else {
unreachable!()
}
}
addr if !addr.is_ref() => {
let h = machine_st.heap.h();
let stub = MachineError::functor_stub(clause_name!("compare"), 3);
let err = MachineError::type_error(h, ValidType::Atom, a1);
return Err(machine_st.error_form(err, stub));
}
_ => {
}
}
let atom = match machine_st.compare_term_test(&a2, &a3) {
Some(Ordering::Greater) => {
let spec = fetch_atom_op_spec(clause_name!(">"), None, &indices.op_dir);
HeapCellValue::Atom(clause_name!(">"), spec)
}
Some(Ordering::Equal) => {
let spec = fetch_atom_op_spec(clause_name!("="), None, &indices.op_dir);
HeapCellValue::Atom(clause_name!("="), spec)
}
None | Some(Ordering::Less) => {
let spec = fetch_atom_op_spec(clause_name!("<"), None, &indices.op_dir);
HeapCellValue::Atom(clause_name!("<"), spec)
}
};
let h = machine_st.heap.h();
machine_st.heap.push(atom);
machine_st.unify(a1, Addr::Con(h));
return_from_clause!(machine_st.last_call, machine_st)
}
&BuiltInClauseType::CompareTerm(qt) => {
machine_st.compare_term(qt);
return_from_clause!(machine_st.last_call, machine_st)
}
&BuiltInClauseType::Nl => {
write!(current_output_stream, "\n").unwrap();
current_output_stream.flush().unwrap();
return_from_clause!(machine_st.last_call, machine_st)
}
&BuiltInClauseType::Read => {
let mut stream = machine_st.open_parsing_stream(
current_input_stream.clone(),
"read",
1,
)?;
match machine_st.read(
&mut stream,
indices.atom_tbl.clone(),
&indices.op_dir,
) {
Ok(offset) => {
let addr = machine_st[temp_v!(1)];
machine_st.unify(addr, Addr::HeapCell(offset.heap_loc));
}
Err(ParserError::UnexpectedEOF) => {
let addr = machine_st[temp_v!(1)];
let eof = clause_name!("end_of_file".to_string(),
indices.atom_tbl);
let atom = machine_st.heap.to_unifiable(
HeapCellValue::Atom(eof, None)
);
machine_st.unify(addr, atom);
}
Err(e) => {
let h = machine_st.heap.h();
let stub = MachineError::functor_stub(clause_name!("read"), 1);
let err = MachineError::syntax_error(h, e);
let err = machine_st.error_form(err, stub);
return Err(err);
}
};
return_from_clause!(machine_st.last_call, machine_st)
}
&BuiltInClauseType::CopyTerm => {
machine_st.copy_term(AttrVarPolicy::DeepCopy);
return_from_clause!(machine_st.last_call, machine_st)
}
&BuiltInClauseType::Eq => {
let a1 = machine_st[temp_v!(1)];
let a2 = machine_st[temp_v!(2)];
machine_st.fail = machine_st.eq_test(a1, a2);
return_from_clause!(machine_st.last_call, machine_st)
}
&BuiltInClauseType::Ground => {
machine_st.fail = machine_st.ground_test();
return_from_clause!(machine_st.last_call, machine_st)
}
&BuiltInClauseType::Functor => {
machine_st.try_functor(&indices)?;
return_from_clause!(machine_st.last_call, machine_st)
}
&BuiltInClauseType::NotEq => {
let a1 = machine_st[temp_v!(1)];
let a2 = machine_st[temp_v!(2)];
machine_st.fail =
if let Some(Ordering::Equal) = machine_st.compare_term_test(&a1, &a2) {
true
} else {
false
};
return_from_clause!(machine_st.last_call, machine_st)
}
&BuiltInClauseType::Sort => {
machine_st.check_sort_errors()?;
let stub = MachineError::functor_stub(clause_name!("sort"), 2);
let mut list = machine_st.try_from_list(temp_v!(1), stub)?;
list.sort_unstable_by(|a1, a2| {
machine_st.compare_term_test(a1, a2).unwrap_or(Ordering::Less)
});
machine_st.term_dedup(&mut list);
let heap_addr = Addr::HeapCell(machine_st.heap.to_list(list.into_iter()));
let r2 = machine_st[temp_v!(2)];
machine_st.unify(r2, heap_addr);
return_from_clause!(machine_st.last_call, machine_st)
}
&BuiltInClauseType::KeySort => {
machine_st.check_keysort_errors()?;
let stub = MachineError::functor_stub(clause_name!("keysort"), 2);
let list = machine_st.try_from_list(temp_v!(1), stub)?;
let mut key_pairs = Vec::new();
for val in list {
let key = machine_st.project_onto_key(val.clone())?;
key_pairs.push((key, val.clone()));
}
key_pairs.sort_by(|a1, a2| {
machine_st.compare_term_test(&a1.0, &a2.0).unwrap_or(Ordering::Less)
});
let key_pairs = key_pairs.into_iter().map(|kp| kp.1);
let heap_addr = Addr::HeapCell(machine_st.heap.to_list(key_pairs));
let r2 = machine_st[temp_v!(2)];
machine_st.unify(r2, heap_addr);
return_from_clause!(machine_st.last_call, machine_st)
}
&BuiltInClauseType::Is(r, ref at) => {
let a1 = machine_st[r];
let n2 = machine_st.get_number(at)?;
let n2 = machine_st.heap.put_constant(n2.into());
machine_st.unify(a1, n2);
return_from_clause!(machine_st.last_call, machine_st)
}
}
}
fn compile_hook(
&mut self,
machine_st: &mut MachineState,
hook: &CompileTimeHook,
) -> CallResult {
machine_st.cp = LocalCodePtr::TopLevel(0, 0);
machine_st.num_of_args = hook.arity();
machine_st.b0 = machine_st.b;
machine_st.p = match hook {
CompileTimeHook::UserTermExpansion | CompileTimeHook::TermExpansion => {
CodePtr::Local(LocalCodePtr::UserTermExpansion(0))
}
CompileTimeHook::UserGoalExpansion | CompileTimeHook::GoalExpansion => {
CodePtr::Local(LocalCodePtr::UserGoalExpansion(0))
}
};
Ok(())
}
fn call_n(
&mut self,
machine_st: &mut MachineState,
arity: usize,
indices: &mut IndexStore,
current_input_stream: &mut Stream,
current_output_stream: &mut Stream,
) -> CallResult {
if let Some((name, arity)) = machine_st.setup_call_n(arity) {
match ClauseType::from(name.clone(), arity, None) {
ClauseType::BuiltIn(built_in) => {
machine_st.setup_built_in_call(built_in.clone());
self.call_builtin(
machine_st,
&built_in,
indices,
current_input_stream,
current_output_stream,
)?;
}
ClauseType::CallN => {
machine_st.handle_internal_call_n(arity);
if machine_st.fail {
return Ok(());
}
machine_st.p = CodePtr::CallN(arity, machine_st.p.local(), machine_st.last_call);
}
ClauseType::Inlined(inlined) => {
machine_st.execute_inlined(&inlined);
if machine_st.last_call {
machine_st.p = CodePtr::Local(machine_st.cp);
}
}
ClauseType::Op(..) | ClauseType::Named(..) => {
let module = name.owning_module();
if let Some(idx) = indices.get_code_index((name.clone(), arity), module) {
self.context_call(machine_st, name, arity, idx, indices)?;
} else {
try_in_situ(machine_st, name, arity, indices, machine_st.last_call)?;
}
}
ClauseType::Hook(_) | ClauseType::System(_) => {
let name = functor!(clause_name(name));
let stub = MachineError::functor_stub(clause_name!("call"), arity + 1);
return Err(machine_st.error_form(
MachineError::type_error(machine_st.heap.h(), ValidType::Callable, name),
stub,
));
}
};
}
Ok(())
}
}
impl CallPolicy for CWILCallPolicy {
fn context_call(
&mut self,
machine_st: &mut MachineState,
name: ClauseName,
arity: usize,
idx: CodeIndex,
indices: &mut IndexStore,
) -> CallResult {
self.prev_policy
.context_call(machine_st, name, arity, idx, indices)?;
self.increment(machine_st)
}
fn retry_me_else(&mut self, machine_st: &mut MachineState, offset: usize) -> CallResult {
self.prev_policy.retry_me_else(machine_st, offset)?;
self.increment(machine_st)
}
fn retry(&mut self, machine_st: &mut MachineState, offset: usize) -> CallResult {
self.prev_policy.retry(machine_st, offset)?;
self.increment(machine_st)
}
fn trust_me(&mut self, machine_st: &mut MachineState) -> CallResult {
self.prev_policy.trust_me(machine_st)?;
self.increment(machine_st)
}
fn trust(&mut self, machine_st: &mut MachineState, offset: usize) -> CallResult {
self.prev_policy.trust(machine_st, offset)?;
self.increment(machine_st)
}
fn call_builtin(
&mut self,
machine_st: &mut MachineState,
ct: &BuiltInClauseType,
indices: &mut IndexStore,
current_input_stream: &mut Stream,
current_output_stream: &mut Stream,
) -> CallResult {
self.prev_policy.call_builtin(
machine_st,
ct,
indices,
current_input_stream,
current_output_stream
)?;
self.increment(machine_st)
}
fn call_n(
&mut self,
machine_st: &mut MachineState,
arity: usize,
indices: &mut IndexStore,
current_input_stream: &mut Stream,
current_output_stream: &mut Stream,
) -> CallResult {
self.prev_policy.call_n(
machine_st,
arity,
indices,
current_input_stream,
current_output_stream,
)?;
self.increment(machine_st)
}
}
downcast!(dyn CallPolicy);
#[derive(Debug)]
pub(crate) struct DefaultCallPolicy {}
impl CallPolicy for DefaultCallPolicy {}
#[derive(Debug)]
pub(crate) struct CWILCallPolicy {
pub(crate) prev_policy: Box<dyn CallPolicy>,
count: Integer,
limits: Vec<(Integer, usize)>,
inference_limit_exceeded: bool,
}
impl CWILCallPolicy {
pub(crate)
fn new_in_place(policy: &mut Box<dyn CallPolicy>) {
let mut prev_policy: Box<dyn CallPolicy> = Box::new(DefaultCallPolicy {});
mem::swap(&mut prev_policy, policy);
let new_policy = CWILCallPolicy {
prev_policy,
count: Integer::from(0),
limits: vec![],
inference_limit_exceeded: false,
};
*policy = Box::new(new_policy);
}
fn increment(&mut self, machine_st: &MachineState) -> CallResult {
if self.inference_limit_exceeded || machine_st.ball.stub.h() > 0 {
return Ok(());
}
if let Some(&(ref limit, bp)) = self.limits.last() {
if self.count == *limit {
self.inference_limit_exceeded = true;
return Err(functor!(
"inference_limit_exceeded",
[addr(Addr::Usize(bp))]
));
} else {
self.count += 1;
}
}
Ok(())
}
pub(crate)
fn add_limit(&mut self, mut limit: Integer, b: usize) -> &Integer {
limit += &self.count;
match self.limits.last().cloned() {
Some((ref inner_limit, _)) if *inner_limit <= limit => {}
_ => self.limits.push((limit, b)),
};
&self.count
}
pub(crate)
fn remove_limit(&mut self, b: usize) -> &Integer {
if let Some((_, bp)) = self.limits.last().cloned() {
if bp == b {
self.limits.pop();
}
}
&self.count
}
pub(crate)
fn is_empty(&self) -> bool {
self.limits.is_empty()
}
pub(crate)
fn into_inner(&mut self) -> Box<dyn CallPolicy> {
let mut new_inner: Box<dyn CallPolicy> = Box::new(DefaultCallPolicy {});
mem::swap(&mut self.prev_policy, &mut new_inner);
new_inner
}
}
pub(crate) trait CutPolicy: Any + fmt::Debug {
// returns true iff we fail or cut redirected the MachineState's p itself
fn cut(&mut self, machine_st: &mut MachineState, r: RegType) -> bool;
}
downcast!(dyn CutPolicy);
fn cut_body(machine_st: &mut MachineState, addr: &Addr) -> bool {
let b = machine_st.b;
match addr {
&Addr::CutPoint(b0) | &Addr::Usize(b0) => {
if b > b0 {
machine_st.b = b0;
machine_st.tidy_trail();
}
}
_ => {
machine_st.fail = true;
return true;
}
};
false
}
#[derive(Debug)]
pub(crate) struct DefaultCutPolicy {}
pub(super) fn deref_cut(machine_st: &mut MachineState, r: RegType) {
let addr = machine_st.store(machine_st.deref(machine_st[r]));
cut_body(machine_st, &addr);
}
impl CutPolicy for DefaultCutPolicy {
fn cut(&mut self, machine_st: &mut MachineState, r: RegType) -> bool {
let addr = machine_st[r];
cut_body(machine_st, &addr)
}
}
#[derive(Debug)]
pub(crate) struct SCCCutPolicy {
// locations of cleaners, cut points, the previous block
cont_pts: Vec<(Addr, usize, usize)>,
r_c_w_h: usize,
r_c_wo_h: usize,
}
impl SCCCutPolicy {
pub(crate) fn new(r_c_w_h: usize, r_c_wo_h: usize) -> Self {
SCCCutPolicy {
cont_pts: vec![],
r_c_w_h,
r_c_wo_h,
}
}
pub(crate) fn out_of_cont_pts(&self) -> bool {
self.cont_pts.is_empty()
}
pub(crate) fn push_cont_pt(&mut self, addr: Addr, b: usize, prev_b: usize) {
self.cont_pts.push((addr, b, prev_b));
}
pub(crate) fn pop_cont_pt(&mut self) -> Option<(Addr, usize, usize)> {
self.cont_pts.pop()
}
fn run_cleaners(&self, machine_st: &mut MachineState) -> bool {
if let Some(&(_, b_cutoff, prev_block)) = self.cont_pts.last() {
if machine_st.b < b_cutoff {
let (idx, arity) = if machine_st.block < prev_block {
(dir_entry!(self.r_c_w_h), 0)
} else {
machine_st[temp_v!(1)] = Addr::Usize(b_cutoff);
(dir_entry!(self.r_c_wo_h), 1)
};
if machine_st.last_call {
machine_st.execute_at_index(arity, idx);
} else {
machine_st.call_at_index(arity, idx);
}
return true;
}
}
false
}
}
impl CutPolicy for SCCCutPolicy {
fn cut(&mut self, machine_st: &mut MachineState, r: RegType) -> bool {
let b = machine_st.b;
match machine_st[r] {
Addr::Usize(b0) | Addr::CutPoint(b0) => {
if b > b0 {
machine_st.b = b0;
machine_st.tidy_trail();
}
}
_ => {
machine_st.fail = true;
return true;
}
}
self.run_cleaners(machine_st)
}
}