use prolog_parser::ast::*;
use prolog::clause_types::*;
use prolog::forms::*;
use prolog::machine::machine_indices::*;
use std::cell::Cell;
use std::collections::VecDeque;
use std::iter::*;
use std::rc::Rc;
use std::vec::Vec;
#[derive(Clone)]
pub enum TermRef<'a> {
AnonVar(Level),
Cons(Level, &'a Cell<RegType>, &'a Term, &'a Term),
Constant(Level, &'a Cell<RegType>, &'a Constant),
Clause(Level, &'a Cell<RegType>, ClauseType, &'a Vec<Box<Term>>),
Var(Level, &'a Cell<VarReg>, Rc<Var>)
}
impl<'a> TermRef<'a> {
pub fn level(self) -> Level {
match self {
TermRef::AnonVar(lvl)
| TermRef::Cons(lvl, ..)
| TermRef::Constant(lvl, ..)
| TermRef::Var(lvl, ..)
| TermRef::Clause(lvl, ..) => lvl
}
}
}
pub enum TermIterState<'a> {
AnonVar(Level),
Constant(Level, &'a Cell<RegType>, &'a Constant),
Clause(Level, usize, &'a Cell<RegType>, ClauseType, &'a Vec<Box<Term>>),
InitialCons(Level, &'a Cell<RegType>, &'a Term, &'a Term),
FinalCons(Level, &'a Cell<RegType>, &'a Term, &'a Term),
Var(Level, &'a Cell<VarReg>, Rc<Var>)
}
impl<'a> TermIterState<'a> {
pub fn subterm_to_state(lvl: Level, term: &'a Term) -> TermIterState<'a> {
match term {
&Term::AnonVar =>
TermIterState::AnonVar(lvl),
&Term::Clause(ref cell, ref name, ref subterms, spec) => {
let ct = if let Some(spec) = spec {
let op_decl = OpDecl(spec.0, spec.1, name.clone());
ClauseType::Op(op_decl, CodeIndex::default())
} else {
ClauseType::Named(name.clone(), subterms.len(), CodeIndex::default())
};
TermIterState::Clause(lvl, 0, cell, ct, subterms)
},
&Term::Cons(ref cell, ref head, ref tail) =>
TermIterState::InitialCons(lvl, cell, head.as_ref(), tail.as_ref()),
&Term::Constant(ref cell, ref constant) =>
TermIterState::Constant(lvl, cell, constant),
&Term::Var(ref cell, ref var) =>
TermIterState::Var(lvl, cell, var.clone())
}
}
}
pub struct QueryIterator<'a> {
state_stack: Vec<TermIterState<'a>>,
}
impl<'a> QueryIterator<'a> {
fn push_subterm(&mut self, lvl: Level, term: &'a Term) {
self.state_stack.push(TermIterState::subterm_to_state(lvl, term));
}
fn from_rule_head_clause(terms: &'a Vec<Box<Term>>) -> Self {
let state_stack = terms.iter().rev()
.map(|bt| TermIterState::subterm_to_state(Level::Shallow, bt.as_ref()))
.collect();
QueryIterator { state_stack }
}
fn from_term(term: &'a Term) -> Self {
let state = match term {
&Term::AnonVar =>
return QueryIterator { state_stack: vec![] },
&Term::Clause(ref r, ref name, ref terms, fixity) =>
TermIterState::Clause(Level::Root, 0, r,
ClauseType::from(name.clone(), terms.len(), fixity),
terms),
&Term::Cons(..) =>
return QueryIterator { state_stack: vec![] },
&Term::Constant(_, _) =>
return QueryIterator { state_stack: vec![] },
&Term::Var(ref cell, ref var) =>
TermIterState::Var(Level::Root, cell, (*var).clone())
};
QueryIterator { state_stack: vec![state] }
}
fn new(term: &'a QueryTerm) -> Self {
match term {
&QueryTerm::Clause(ref cell, ClauseType::CallN, ref terms, _) => {
let state = TermIterState::Clause(Level::Root, 1, cell, ClauseType::CallN, terms);
QueryIterator { state_stack: vec![state] }
},
&QueryTerm::Clause(ref cell, ref ct, ref terms, _) => {
let state = TermIterState::Clause(Level::Root, 0, cell, ct.clone(), terms);
QueryIterator { state_stack: vec![state] }
},
&QueryTerm::UnblockedCut(ref cell) => {
let state = TermIterState::Var(Level::Root, cell, rc_atom!("!"));
QueryIterator { state_stack: vec![state] }
},
&QueryTerm::GetLevelAndUnify(ref cell, ref var) => {
let state = TermIterState::Var(Level::Root, cell, var.clone());
QueryIterator { state_stack: vec![state] }
},
&QueryTerm::Jump(ref vars) => {
let state_stack = vars.iter().rev().map(|t| {
TermIterState::subterm_to_state(Level::Shallow, t)
}).collect();
QueryIterator { state_stack }
},
&QueryTerm::BlockedCut =>
QueryIterator { state_stack: vec![] },
}
}
}
impl<'a> Iterator for QueryIterator<'a> {
type Item = TermRef<'a>;
fn next(&mut self) -> Option<Self::Item> {
while let Some(iter_state) = self.state_stack.pop() {
match iter_state {
TermIterState::AnonVar(lvl) =>
return Some(TermRef::AnonVar(lvl)),
TermIterState::Clause(lvl, child_num, cell, ct, child_terms) => {
if child_num == child_terms.len() {
match ct {
ClauseType::CallN =>
self.push_subterm(Level::Shallow, child_terms[0].as_ref()),
ClauseType::Named(..) | ClauseType::Op(..) =>
return match lvl {
Level::Root => None,
lvl => Some(TermRef::Clause(lvl, cell, ct, child_terms))
},
_ =>
return None
};
} else {
self.state_stack.push(TermIterState::Clause(lvl, child_num + 1,
cell, ct, child_terms));
self.push_subterm(lvl.child_level(), child_terms[child_num].as_ref());
}
},
TermIterState::InitialCons(lvl, cell, head, tail) => {
self.state_stack.push(TermIterState::FinalCons(lvl, cell, head, tail));
self.push_subterm(lvl.child_level(), tail);
self.push_subterm(lvl.child_level(), head);
},
TermIterState::FinalCons(lvl, cell, head, tail) =>
return Some(TermRef::Cons(lvl, cell, head, tail)),
TermIterState::Constant(lvl, cell, constant) =>
return Some(TermRef::Constant(lvl, cell, constant)),
TermIterState::Var(lvl, cell, var) =>
return Some(TermRef::Var(lvl, cell, var))
};
}
None
}
}
pub struct FactIterator<'a> {
state_queue: VecDeque<TermIterState<'a>>,
iterable_root: bool
}
impl<'a> FactIterator<'a> {
fn push_subterm(&mut self, lvl: Level, term: &'a Term) {
self.state_queue.push_back(TermIterState::subterm_to_state(lvl, term));
}
pub fn from_rule_head_clause(terms: &'a Vec<Box<Term>>) -> Self {
let state_queue = terms.iter()
.map(|bt| TermIterState::subterm_to_state(Level::Shallow, bt.as_ref()))
.collect();
FactIterator { state_queue, iterable_root: false }
}
fn new(term: &'a Term, iterable_root: bool) -> Self {
let states = match term {
&Term::AnonVar =>
vec![TermIterState::AnonVar(Level::Root)],
&Term::Clause(ref cell, ref name, ref terms, fixity) => {
let ct = ClauseType::from(name.clone(), terms.len(), fixity);
vec![TermIterState::Clause(Level::Root, 0, cell, ct, terms)]
},
&Term::Cons(ref cell, ref head, ref tail) =>
vec![TermIterState::InitialCons(Level::Root, cell, head.as_ref(), tail.as_ref())],
&Term::Constant(ref cell, ref constant) =>
vec![TermIterState::Constant(Level::Root, cell, constant)],
&Term::Var(ref cell, ref var) =>
vec![TermIterState::Var(Level::Root, cell, var.clone())]
};
FactIterator { state_queue: VecDeque::from(states), iterable_root }
}
}
impl<'a> Iterator for FactIterator<'a> {
type Item = TermRef<'a>;
fn next(&mut self) -> Option<Self::Item> {
while let Some(state) = self.state_queue.pop_front() {
match state {
TermIterState::AnonVar(lvl) =>
return Some(TermRef::AnonVar(lvl)),
TermIterState::Clause(lvl, _, cell, ct, child_terms) => {
for child_term in child_terms {
self.push_subterm(lvl.child_level(), child_term);
}
match lvl {
Level::Root if !self.iterable_root => continue,
_ => return Some(TermRef::Clause(lvl, cell, ct, child_terms))
};
},
TermIterState::InitialCons(lvl, cell, head, tail) => {
self.push_subterm(Level::Deep, head);
self.push_subterm(Level::Deep, tail);
return Some(TermRef::Cons(lvl, cell, head, tail));
},
TermIterState::Constant(lvl, cell, constant) =>
return Some(TermRef::Constant(lvl, cell, constant)),
TermIterState::Var(lvl, cell, var) =>
return Some(TermRef::Var(lvl, cell, var)),
_ => {}
}
}
None
}
}
pub fn post_order_iter(term: &Term) -> QueryIterator {
QueryIterator::from_term(term)
}
pub fn breadth_first_iter(term: &Term, iterable_root: bool) -> FactIterator {
FactIterator::new(term, iterable_root)
}
pub enum ChunkedTerm<'a> {
HeadClause(ClauseName, &'a Vec<Box<Term>>),
BodyTerm(&'a QueryTerm)
}
pub fn query_term_post_order_iter<'a>(query_term: &'a QueryTerm) -> QueryIterator<'a> {
QueryIterator::new(query_term)
}
impl<'a> ChunkedTerm<'a> {
pub fn post_order_iter(&self) -> QueryIterator<'a> {
match self {
&ChunkedTerm::BodyTerm(ref qt) =>
QueryIterator::new(qt),
&ChunkedTerm::HeadClause(_, terms) =>
QueryIterator::from_rule_head_clause(terms)
}
}
}
fn contains_cut_var<'a, Iter: Iterator<Item=&'a Term>>(terms: Iter) -> bool {
for term in terms {
if let &Term::Var(_, ref var) = term {
if var.as_str() == "!" {
return true;
}
}
}
false
}
pub struct ChunkedIterator<'a>
{
pub chunk_num: usize,
iter: Box<Iterator<Item=ChunkedTerm<'a>> + 'a>,
deep_cut_encountered: bool,
cut_var_in_head: bool
}
type ChunkedIteratorItem<'a> = (usize, usize, Vec<ChunkedTerm<'a>>);
type RuleBodyIteratorItem<'a> = (usize, usize, Vec<&'a QueryTerm>);
impl<'a> ChunkedIterator<'a>
{
pub fn rule_body_iter(self) -> Box<Iterator<Item=RuleBodyIteratorItem<'a>> + 'a>
{
Box::new(self.filter_map(|(cn, lt_arity, terms)| {
let filtered_terms: Vec<_> = terms.into_iter().filter_map(|ct| {
match ct {
ChunkedTerm::BodyTerm(qt) => Some(qt),
_ => None
}
}).collect();
if filtered_terms.is_empty() {
None
} else {
Some((cn, lt_arity, filtered_terms))
}
}))
}
pub fn from_term_sequence(terms: &'a [QueryTerm]) -> Self
{
ChunkedIterator {
chunk_num: 0,
iter: Box::new(terms.iter().map(|t| ChunkedTerm::BodyTerm(t))),
deep_cut_encountered: false,
cut_var_in_head: false
}
}
pub fn from_rule_body(p1: &'a QueryTerm, clauses: &'a Vec<QueryTerm>) -> Self
{
let inner_iter = Box::new(once(ChunkedTerm::BodyTerm(p1)));
let iter = inner_iter.chain(clauses.iter().map(|t| ChunkedTerm::BodyTerm(t)));
ChunkedIterator {
chunk_num: 0,
iter: Box::new(iter),
deep_cut_encountered: false,
cut_var_in_head: false
}
}
pub fn from_rule(rule: &'a Rule) -> Self
{
let &Rule { head: (ref name, ref args, ref p1), ref clauses } = rule;
let iter = once(ChunkedTerm::HeadClause(name.clone(), args));
let inner_iter = Box::new(once(ChunkedTerm::BodyTerm(p1)));
let iter = iter.chain(inner_iter.chain(clauses.iter().map(|t| ChunkedTerm::BodyTerm(t))));
ChunkedIterator {
chunk_num: 0,
iter: Box::new(iter),
deep_cut_encountered: false,
cut_var_in_head: false
}
}
pub fn encountered_deep_cut(&self) -> bool {
self.deep_cut_encountered
}
fn take_chunk(&mut self, term: ChunkedTerm<'a>) -> (usize, usize, Vec<ChunkedTerm<'a>>)
{
let mut arity = 0;
let mut item = Some(term);
let mut result = Vec::new();
while let Some(term) = item {
match term {
ChunkedTerm::HeadClause(_, terms) => {
if contains_cut_var(terms.iter().map(|t| t.as_ref())) {
self.cut_var_in_head = true;
}
result.push(term);
},
ChunkedTerm::BodyTerm(&QueryTerm::Jump(ref vars)) => {
result.push(term);
arity = vars.len();
if contains_cut_var(vars.iter()) && !self.cut_var_in_head {
self.deep_cut_encountered = true;
}
break;
},
ChunkedTerm::BodyTerm(&QueryTerm::BlockedCut) => {
result.push(term);
if self.chunk_num > 0 {
self.deep_cut_encountered = true;
}
},
ChunkedTerm::BodyTerm(&QueryTerm::GetLevelAndUnify(..)) => {
self.deep_cut_encountered = true;
result.push(term);
arity = 1;
break;
},
ChunkedTerm::BodyTerm(&QueryTerm::UnblockedCut(..)) =>
result.push(term),
ChunkedTerm::BodyTerm(&QueryTerm::Clause(_, ClauseType::Inlined(_), ..)) =>
result.push(term),
ChunkedTerm::BodyTerm(&QueryTerm::Clause(_, ClauseType::CallN, ref subterms, _)) => {
result.push(term);
arity = subterms.len() + 1;
break;
},
ChunkedTerm::BodyTerm(qt) => {
result.push(term);
arity = qt.arity();
break;
}
};
item = self.iter.next();
}
let chunk_num = self.chunk_num;
self.chunk_num += 1;
(chunk_num, arity, result)
}
}
impl<'a> Iterator for ChunkedIterator<'a>
{
type Item = ChunkedIteratorItem<'a>;
fn next(&mut self) -> Option<Self::Item> {
self.iter.next().map(|term| self.take_chunk(term))
}
}