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use crate::nameless::{NamelessClause, NamelessPredicate, NamelessQuery, NamelessValue};
use std::{collections::HashSet, iter::once, sync::Arc};
pub fn naive_solve_selfcontained(query: &NamelessQuery) -> Vec<Vec<Arc<str>>> {
naive_solve(&[], &[], &[], &[], &[], None, query)
}
pub fn naive_solve(
atoms: &[Arc<str>],
names: &[(Arc<str>, Arc<str>, Arc<str>)],
edges: &[(Arc<str>, Arc<str>, Arc<str>)],
tags: &[(Arc<str>, Arc<str>, Arc<str>)],
blobs: &[(Arc<str>, Arc<str>, Arc<str>, Arc<str>)],
limit: Option<usize>,
query: &NamelessQuery,
) -> Vec<Vec<Arc<str>>> {
let mut tuples = vec![HashSet::new(); query.clauses.len() + 5];
tuples[0].extend(atoms.iter().map(|atom| vec![atom.clone()]));
tuples[1].extend(
names
.iter()
.map(|(atom, ns, title)| vec![atom.clone(), ns.clone(), title.clone()]),
);
tuples[2].extend(
edges
.iter()
.map(|(to, from, label)| vec![to.clone(), from.clone(), label.clone()]),
);
tuples[3].extend(
tags.iter()
.map(|(atom, key, value)| vec![atom.clone(), key.clone(), value.clone()]),
);
tuples[4].extend(blobs.iter().map(|(atom, kind, mime, hash)| {
vec![atom.clone(), kind.clone(), mime.clone(), hash.clone()]
}));
for (pred_idx, pred) in query.clauses.iter().enumerate() {
loop {
let mut new_tuples = HashSet::new();
for clause in pred {
new_tuples.extend(compute_new_tuples(&tuples, clause));
}
new_tuples.retain(|x| !tuples[pred_idx + 5].contains(x));
if new_tuples.is_empty() {
break;
}
tuples[pred_idx + 5].extend(new_tuples);
}
}
let iter = tuples
.remove(query.goal.name as usize)
.into_iter()
.filter(|tuple| {
let mut vars = (0..query.goal_vars).map(|_| None).collect::<Vec<_>>();
tuple
.iter()
.zip(&query.goal.args)
.all(|(val, arg)| match arg {
NamelessValue::Str(s) => s == val,
NamelessValue::Var(n) => match &vars[*n as usize] {
Some(s) => s == &val,
None => {
vars[*n as usize] = Some(val);
true
}
},
})
});
if let Some(limit) = limit {
iter.take(limit).collect()
} else {
iter.collect()
}
}
fn compute_new_tuples(
tuples: &Vec<HashSet<Vec<Arc<str>>>>,
clause: &NamelessClause,
) -> HashSet<Vec<Arc<str>>> {
assert!(clause.body_neg.is_empty(), "TODO negation");
make_envs(tuples, &clause.body_pos, clause.vars)
.map(|env| {
clause
.head
.iter()
.map(|x| match x {
NamelessValue::Str(s) => s,
NamelessValue::Var(n) => env[*n as usize].as_ref().unwrap(),
})
.cloned()
.collect()
})
.collect()
}
fn make_envs<'a>(
tuples: &'a Vec<HashSet<Vec<Arc<str>>>>,
body: &'a [NamelessPredicate],
vars: u32,
) -> Box<dyn Iterator<Item = Vec<Option<Arc<str>>>> + 'a> {
if body.is_empty() {
Box::new(once((0..vars).map(|_| None).collect::<Vec<_>>()))
} else {
let pred = &body[0];
Box::new(make_envs(tuples, &body[1..], vars).flat_map(move |env| {
tuples[pred.name as usize].iter().filter_map(move |tuple| {
let mut env = env.clone();
for (arg, val) in pred.args.iter().zip(tuple) {
match arg {
NamelessValue::Str(s) => {
if s != val {
return None;
}
}
NamelessValue::Var(n) => {
let slot = &mut env[*n as usize];
if let Some(s) = slot {
if s != val {
return None;
}
} else {
*slot = Some(val.clone());
}
}
}
}
Some(env)
})
}))
}
}