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mthom's changes fixing the panic

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This commit is contained in:
Nicolas Luck
2023-09-18 13:01:27 +02:00
parent c86304b18e
commit d2f5291412
1 changed files with 49 additions and 7 deletions
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50
src/machine/lib_machine.rs
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@@ -35,6 +35,28 @@ impl Machine {
self.run_module_predicate(atom!("loader"), (atom!("consult_stream"), 2));
}
fn allocate_stub_choice_point(&mut self) {
// NOTE: create a choice point to terminate the dispatch_loop
// if an exception is thrown. since the and/or stack is presumed empty,
let stub_b = self.machine_st.stack.allocate_or_frame(0);
let or_frame = self.machine_st.stack.index_or_frame_mut(0);
or_frame.prelude.num_cells = 0;
or_frame.prelude.e = 0;
or_frame.prelude.cp = 0;
or_frame.prelude.b = 0;
or_frame.prelude.bp = BREAK_FROM_DISPATCH_LOOP_LOC;
or_frame.prelude.boip = 0;
or_frame.prelude.biip = 0;
or_frame.prelude.tr = 0;
or_frame.prelude.h = 0;
or_frame.prelude.b0 = 0;
or_frame.prelude.attr_var_queue_len = 0;
self.machine_st.b = stub_b;
}
pub fn run_query(&mut self, query: String) -> QueryResult {
println!("Query: {}", query);
// Parse the query so we can analyze and then call the term
@@ -64,6 +86,10 @@ impl Machine {
})
.collect();
self.allocate_stub_choice_point();
let stub_b = self.machine_st.b;
let mut matches: Vec<QueryResolutionLine> = Vec::new();
// Call the term
loop {
@@ -75,6 +101,14 @@ impl Machine {
println!("false");
matches.push(QueryResolutionLine::False);
break;
} else if self.machine_st.ball.stub.len() != 0 {
// NOTE: this means an exception was thrown, at which
// point we backtracked to the stub choice point.
// this should halt the search for solutions as it
// does in the Scryer top-level. the exception term is
// contained in self.machine_st.ball.
println!("exception thrown");
break;
}
let mut bindings: BTreeMap<String, Value> = BTreeMap::new();
@@ -109,11 +143,14 @@ impl Machine {
matches.push(QueryResolutionLine::Match(bindings));
if self.machine_st.b > 0 {
// NOTE: there are outstanding choicepoints, backtrack
// through them for further solutions. if
// self.machine_st.b == stub_b we've backtracked to the stub
// choice point, so we should break.
self.machine_st.backtrack();
if self.machine_st.b > stub_b {
println!("b: {}", self.machine_st.b);
// NOTE: there are outstanding choicepoints, backtrack
// through them for further solutions.
self.machine_st.backtrack();
} else {
println!("breaking");
// NOTE: out of choicepoints to backtrack through, no
@@ -122,6 +159,11 @@ impl Machine {
}
}
// NOTE: deallocate stub choice point
if self.machine_st.b == stub_b {
self.trust_me();
}
Ok(QueryResolution::from(matches))
}
}