521 lines
20 KiB
Rust
521 lines
20 KiB
Rust
use prolog_parser::ast::*;
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use prolog::heap_iter::*;
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use prolog::heap_print::*;
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use prolog::instructions::*;
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use prolog::machine::IndexStore;
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use prolog::machine::machine_errors::*;
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use prolog::machine::machine_state::*;
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use prolog::num::{ToPrimitive, Zero};
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use prolog::num::bigint::{BigInt};
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use std::collections::HashSet;
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use std::rc::Rc;
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struct BrentAlgState {
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hare: usize,
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tortoise: usize,
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power: usize,
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steps: usize
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}
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impl BrentAlgState {
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fn new(hare: usize) -> Self {
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BrentAlgState { hare, tortoise: hare, power: 2, steps: 1 }
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}
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}
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impl MachineState {
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// a step in Brent's algorithm.
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fn brents_alg_step(&self, brent_st: &mut BrentAlgState) -> Option<CycleSearchResult>
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{
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match self.heap[brent_st.hare].clone() {
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HeapCellValue::Addr(Addr::Lis(l)) => {
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brent_st.hare = l + 1;
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brent_st.steps += 1;
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if brent_st.tortoise == brent_st.hare {
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return Some(CycleSearchResult::NotList);
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} else if brent_st.steps == brent_st.power {
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brent_st.tortoise = brent_st.hare;
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brent_st.power <<= 1;
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}
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None
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},
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HeapCellValue::NamedStr(..) =>
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Some(CycleSearchResult::NotList),
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HeapCellValue::Addr(addr) =>
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match self.store(self.deref(addr)) {
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Addr::Con(Constant::EmptyList) =>
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Some(CycleSearchResult::ProperList(brent_st.steps)),
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Addr::HeapCell(_) | Addr::StackCell(..) =>
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Some(CycleSearchResult::PartialList(brent_st.steps, brent_st.hare)),
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_ =>
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Some(CycleSearchResult::NotList)
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}
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}
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}
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pub(super) fn detect_cycles_with_max(&self, max_steps: usize, addr: Addr) -> CycleSearchResult
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{
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let addr = self.store(self.deref(addr));
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let hare = match addr {
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Addr::Lis(offset) if max_steps > 0 => offset + 1,
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Addr::Lis(offset) => return CycleSearchResult::UntouchedList(offset),
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Addr::Con(Constant::EmptyList) => return CycleSearchResult::EmptyList,
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_ => return CycleSearchResult::NotList
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};
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let mut brent_st = BrentAlgState::new(hare);
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loop {
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if brent_st.steps == max_steps {
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return CycleSearchResult::PartialList(brent_st.steps, brent_st.hare);
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}
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if let Some(result) = self.brents_alg_step(&mut brent_st) {
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return result;
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}
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}
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}
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pub(super) fn detect_cycles(&self, addr: Addr) -> CycleSearchResult
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{
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let addr = self.store(self.deref(addr));
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let hare = match addr {
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Addr::Lis(offset) => offset + 1,
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Addr::Con(Constant::EmptyList) => return CycleSearchResult::EmptyList,
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_ => return CycleSearchResult::NotList
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};
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let mut brent_st = BrentAlgState::new(hare);
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loop {
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if let Some(result) = self.brents_alg_step(&mut brent_st) {
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return result;
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}
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}
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}
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fn finalize_skip_max_list(&mut self, n: usize, addr: Addr) {
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let target_n = self[temp_v!(1)].clone();
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self.unify(Addr::Con(integer!(n)), target_n);
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if !self.fail {
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let xs = self[temp_v!(4)].clone();
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self.unify(addr, xs);
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}
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}
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pub(super) fn skip_max_list(&mut self) -> CallResult {
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let max_steps = self.store(self.deref(self[temp_v!(2)].clone()));
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match max_steps {
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Addr::Con(Constant::Number(Number::Integer(ref max_steps))) =>
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if max_steps.to_isize().map(|i| i >= -1).unwrap_or(false) {
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let n = self.store(self.deref(self[temp_v!(1)].clone()));
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match n {
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Addr::Con(Constant::Number(Number::Integer(ref n))) if n.is_zero() => {
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let xs0 = self[temp_v!(3)].clone();
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let xs = self[temp_v!(4)].clone();
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self.unify(xs0, xs);
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},
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_ => {
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let search_result = if let Some(max_steps) = max_steps.to_isize() {
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if max_steps == -1 {
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self.detect_cycles(self[temp_v!(3)].clone())
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} else {
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self.detect_cycles_with_max(max_steps as usize,
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self[temp_v!(3)].clone())
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}
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} else {
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self.detect_cycles(self[temp_v!(3)].clone())
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};
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match search_result {
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CycleSearchResult::UntouchedList(l) =>
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self.finalize_skip_max_list(0, Addr::Lis(l)),
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CycleSearchResult::EmptyList =>
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self.finalize_skip_max_list(0, Addr::Con(Constant::EmptyList)),
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CycleSearchResult::PartialList(n, hc) =>
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self.finalize_skip_max_list(n, Addr::HeapCell(hc)),
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CycleSearchResult::ProperList(n) =>
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self.finalize_skip_max_list(n, Addr::Con(Constant::EmptyList)),
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CycleSearchResult::NotList => {
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let xs0 = self[temp_v!(3)].clone();
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self.finalize_skip_max_list(0, xs0);
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}
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}
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}
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}
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} else {
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self.fail = true;
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},
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Addr::HeapCell(_) | Addr::StackCell(..) => {
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let stub = MachineError::functor_stub(clause_name!("$skip_max_list"), 4);
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return Err(self.error_form(MachineError::instantiation_error(), stub));
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},
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addr => {
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let stub = MachineError::functor_stub(clause_name!("$skip_max_list"), 4);
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return Err(self.error_form(MachineError::type_error(ValidType::Integer, addr),
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stub));
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}
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};
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Ok(())
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}
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#[inline]
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fn install_new_block(&mut self, r: RegType) -> usize {
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self.block = self.b;
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let c = Constant::Usize(self.block);
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let addr = self[r].clone();
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self.write_constant_to_var(addr, c);
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self.block
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}
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#[inline]
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fn set_p(&mut self) {
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if self.last_call {
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self.p = CodePtr::Local(self.cp.clone());
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} else {
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self.p += 1;
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}
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}
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pub(super) fn system_call(&mut self, ct: &SystemClauseType,
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indices: &IndexStore,
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call_policy: &mut Box<CallPolicy>,
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cut_policy: &mut Box<CutPolicy>)
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-> CallResult
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{
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match ct {
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&SystemClauseType::CheckCutPoint => {
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let addr = self.store(self.deref(self[temp_v!(1)].clone()));
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match addr {
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Addr::Con(Constant::Usize(old_b)) if self.b <= old_b + 2 => {},
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_ => self.fail = true
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};
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},
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&SystemClauseType::ExpandGoal => {
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self.p = CodePtr::Local(LocalCodePtr::UserGoalExpansion(0));
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// return Ok(());
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},
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&SystemClauseType::ExpandTerm => {
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self.p = CodePtr::Local(LocalCodePtr::UserTermExpansion(0));
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// return Ok(());
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},
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&SystemClauseType::GetDoubleQuotes => {
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let a1 = self[temp_v!(1)].clone();
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match self.flags.double_quotes {
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DoubleQuotes::Chars =>
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self.unify(a1, Addr::Con(atom!("chars"))),
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DoubleQuotes::Atom =>
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self.unify(a1, Addr::Con(atom!("atom")))
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}
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},
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&SystemClauseType::GetSCCCleaner => {
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let dest = self[temp_v!(1)].clone();
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match cut_policy.downcast_mut::<SCCCutPolicy>().ok() {
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Some(sgc_policy) =>
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if let Some((addr, b_cutoff, prev_b)) = sgc_policy.pop_cont_pt() {
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if self.b <= b_cutoff + 1 {
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self.block = prev_b;
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if let Some(r) = dest.as_var() {
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self.bind(r, addr.clone());
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self.set_p();
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return Ok(());
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}
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} else {
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sgc_policy.push_cont_pt(addr, b_cutoff, prev_b);
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}
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},
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None => panic!("expected SCCCutPolicy trait object.")
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};
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self.fail = true;
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},
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&SystemClauseType::InstallSCCCleaner => {
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let addr = self[temp_v!(1)].clone();
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let b = self.b;
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let prev_block = self.block;
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if cut_policy.downcast_ref::<SCCCutPolicy>().is_err() {
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let (r_c_w_h, r_c_wo_h) = indices.get_cleaner_sites();
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*cut_policy = Box::new(SCCCutPolicy::new(r_c_w_h, r_c_wo_h));
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}
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match cut_policy.downcast_mut::<SCCCutPolicy>().ok()
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{
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Some(cut_policy) => {
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self.install_new_block(temp_v!(2));
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cut_policy.push_cont_pt(addr, b, prev_block);
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},
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None => panic!("install_cleaner: should have installed \\
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SCCCutPolicy.")
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};
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},
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&SystemClauseType::InstallInferenceCounter => { // A1 = B, A2 = L
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let a1 = self.store(self.deref(self[temp_v!(1)].clone()));
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let a2 = self.store(self.deref(self[temp_v!(2)].clone()));
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if call_policy.downcast_ref::<CWILCallPolicy>().is_err() {
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CWILCallPolicy::new_in_place(call_policy);
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}
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match (a1, a2.clone()) {
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(Addr::Con(Constant::Usize(bp)),
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Addr::Con(Constant::Number(Number::Integer(n)))) =>
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match call_policy.downcast_mut::<CWILCallPolicy>().ok() {
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Some(call_policy) => {
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let count = call_policy.add_limit(n, bp);
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let count = Addr::Con(Constant::Number(Number::Integer(count)));
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let a3 = self[temp_v!(3)].clone();
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self.unify(a3, count);
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},
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None => panic!("install_inference_counter: should have installed \\
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CWILCallPolicy.")
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},
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_ => {
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let stub = MachineError::functor_stub(clause_name!("call_with_inference_limit"), 3);
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let type_error = self.error_form(MachineError::type_error(ValidType::Integer, a2),
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stub);
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self.throw_exception(type_error)
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}
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};
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},
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&SystemClauseType::RemoveCallPolicyCheck => {
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let restore_default =
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match call_policy.downcast_mut::<CWILCallPolicy>().ok() {
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Some(call_policy) => {
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let a1 = self.store(self.deref(self[temp_v!(1)].clone()));
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if let Addr::Con(Constant::Usize(bp)) = a1 {
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if call_policy.is_empty() && bp == self.b {
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Some(call_policy.into_inner())
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} else {
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None
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}
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} else {
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panic!("remove_call_policy_check: expected Usize in A1.");
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}
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},
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None => panic!("remove_call_policy_check: requires \\
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CWILCallPolicy.")
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};
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if let Some(new_policy) = restore_default {
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*call_policy = new_policy;
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}
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},
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&SystemClauseType::RemoveInferenceCounter =>
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match call_policy.downcast_mut::<CWILCallPolicy>().ok() {
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Some(call_policy) => {
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let a1 = self.store(self.deref(self[temp_v!(1)].clone()));
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if let Addr::Con(Constant::Usize(bp)) = a1 {
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let count = call_policy.remove_limit(bp);
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let count = Addr::Con(Constant::Number(Number::Integer(count)));
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let a2 = self[temp_v!(2)].clone();
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self.unify(a2, count);
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} else {
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panic!("remove_inference_counter: expected Usize in A1.");
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}
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},
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None => panic!("remove_inference_counter: requires \\
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CWILCallPolicy.")
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},
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&SystemClauseType::RestoreCutPolicy => {
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let restore_default =
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if let Ok(cut_policy) = cut_policy.downcast_ref::<SCCCutPolicy>() {
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cut_policy.out_of_cont_pts()
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} else {
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false
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};
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if restore_default {
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*cut_policy = Box::new(DefaultCutPolicy {});
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}
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},
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&SystemClauseType::SetCutPoint(r) => if cut_policy.cut(self, r) {
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return Ok(());
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},
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&SystemClauseType::SetCutPointByDefault(r) =>
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deref_cut(self, r),
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&SystemClauseType::SetDoubleQuotes =>
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match self[temp_v!(1)].clone() {
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Addr::Con(Constant::Atom(ref atom, _)) if atom.as_str() == "chars" =>
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self.flags.double_quotes = DoubleQuotes::Chars,
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Addr::Con(Constant::Atom(ref atom, _)) if atom.as_str() == "atom" =>
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self.flags.double_quotes = DoubleQuotes::Atom,
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_ => self.fail = true
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},
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&SystemClauseType::InferenceLevel => {
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let a1 = self[temp_v!(1)].clone();
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let a2 = self.store(self.deref(self[temp_v!(2)].clone()));
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match a2 {
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Addr::Con(Constant::Usize(bp)) =>
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if self.b <= bp + 1 {
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let a2 = Addr::Con(atom!("!"));
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self.unify(a1, a2);
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} else {
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let a2 = Addr::Con(atom!("true"));
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self.unify(a1, a2);
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},
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_ => self.fail = true
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};
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},
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&SystemClauseType::CleanUpBlock => {
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let nb = self.store(self.deref(self[temp_v!(1)].clone()));
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match nb {
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Addr::Con(Constant::Usize(nb)) => {
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let b = self.b - 1;
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if nb > 0 && self.or_stack[b].b == nb {
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self.b = self.or_stack[nb - 1].b;
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self.or_stack.truncate(self.b);
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}
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},
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_ => self.fail = true
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};
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},
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&SystemClauseType::EraseBall => self.ball.reset(),
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&SystemClauseType::Fail => self.fail = true,
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&SystemClauseType::GetBall => {
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let addr = self.store(self.deref(self[temp_v!(1)].clone()));
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let h = self.heap.h;
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if self.ball.stub.len() > 0 {
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self.copy_and_align_ball_to_heap();
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} else {
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self.fail = true;
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return Ok(());
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}
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let ball = self.heap[h].as_addr(h);
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match addr.as_var() {
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Some(r) => self.bind(r, ball),
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_ => self.fail = true
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};
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},
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&SystemClauseType::GetCurrentBlock => {
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let c = Constant::Usize(self.block);
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let addr = self[temp_v!(1)].clone();
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self.write_constant_to_var(addr, c);
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},
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&SystemClauseType::GetBValue => {
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let a1 = self[temp_v!(1)].clone();
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let a2 = Addr::Con(Constant::Usize(self.b));
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self.unify(a1, a2);
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},
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&SystemClauseType::GetCutPoint => {
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let a1 = self[temp_v!(1)].clone();
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let a2 = Addr::Con(Constant::Usize(self.b0));
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self.unify(a1, a2);
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},
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&SystemClauseType::InstallNewBlock => {
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self.install_new_block(temp_v!(1));
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},
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&SystemClauseType::ResetBlock => {
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let addr = self.deref(self[temp_v!(1)].clone());
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self.reset_block(addr);
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},
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&SystemClauseType::SetBall => self.set_ball(),
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&SystemClauseType::SkipMaxList => if let Err(err) = self.skip_max_list() {
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return Err(err);
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},
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&SystemClauseType::Succeed => {},
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&SystemClauseType::TermVariables => {
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let a1 = self[temp_v!(1)].clone();
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let mut vars = Vec::new();
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{
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let iter = HCPreOrderIterator::new(self, a1);
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for item in iter {
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match item {
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HeapCellValue::Addr(Addr::HeapCell(h)) =>
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vars.push(Ref::HeapCell(h)),
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HeapCellValue::Addr(Addr::StackCell(fr, sc)) =>
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vars.push(Ref::StackCell(fr, sc)),
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_ => {}
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}
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}
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}
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let mut h = self.heap.h;
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let outcome = Addr::HeapCell(h);
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let mut seen_vars = HashSet::new();
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for r in vars {
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if seen_vars.contains(&r) {
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continue;
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}
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self.heap.push(HeapCellValue::Addr(Addr::Lis(h+1)));
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self.heap.push(HeapCellValue::Addr(r.as_addr()));
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h += 2;
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seen_vars.insert(r);
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}
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self.heap.push(HeapCellValue::Addr(Addr::Con(Constant::EmptyList)));
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let a2 = self[temp_v!(2)].clone();
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self.unify(a2, outcome);
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},
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&SystemClauseType::UnwindStack => self.unwind_stack(),
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&SystemClauseType::WriteTerm => {
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let addr = self[temp_v!(1)].clone();
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let ignore_ops = self[temp_v!(2)].clone();
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let numbervars = self[temp_v!(3)].clone();
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let quoted = self[temp_v!(4)].clone();
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let mut printer = HCPrinter::new(&self, PrinterOutputter::new());
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if let &Addr::Con(Constant::Atom(ref name, ..)) = &ignore_ops {
|
|
printer.ignore_ops = name.as_str() == "true";
|
|
}
|
|
|
|
if let &Addr::Con(Constant::Atom(ref name, ..)) = &numbervars {
|
|
printer.numbervars = name.as_str() == "true";
|
|
}
|
|
|
|
if let &Addr::Con(Constant::Atom(ref name, ..)) = "ed {
|
|
printer.quoted = name.as_str() == "true";
|
|
}
|
|
|
|
let mut output = printer.print(addr);
|
|
println!("{}", output.result());
|
|
}
|
|
};
|
|
|
|
self.set_p();
|
|
|
|
Ok(())
|
|
}
|
|
}
|