use in situ code directory from metacall if conventional lookup fails (#238)

src/prolog/machine/machine_state.rs

@@ -873,13 +873,7 @@ pub(crate) trait CallPolicy: Any {
                     if let Some(idx) = indices.get_code_index((name.clone(), arity), module) {
                         self.context_call(machine_st, name, arity, idx, indices)?;
                     } else {
-                        let h = machine_st.heap.h;
-                        let stub = MachineError::functor_stub(clause_name!("call"), arity + 1);
-                        let key = ExistenceError::Procedure(name, arity);
-
-                        return Err(
-                            machine_st.error_form(MachineError::existence_error(h, key), stub)
-                        );
+                        try_in_situ(machine_st, name, arity, indices, machine_st.last_call)?;
                     }
                 }
                 ClauseType::Hook(_) | ClauseType::System(_) => {

src/prolog/machine/mod.rs

@@ -107,13 +107,13 @@ impl SubModuleUser for IndexStore {
         &mut self.op_dir
     }
 
-    fn get_code_index(&self, key: PredicateKey, module: ClauseName) -> Option<CodeIndex> {
-        match module.as_str() {
+    fn get_code_index(&self, key: PredicateKey, module_name: ClauseName) -> Option<CodeIndex> {
+        match module_name.as_str() {
             "user" | "builtin" => self.code_dir.get(&key).cloned(),
             _ => self
               .modules
-                .get(&module)
-                .and_then(|ref module| module.code_dir.get(&key).cloned().map(CodeIndex::from)),
+              .get(&module_name)
+              .and_then(|ref module| module.code_dir.get(&key).cloned().map(CodeIndex::from))
         }
     }
 
@@ -132,7 +132,7 @@ impl SubModuleUser for IndexStore {
             return;
         }
 
-        self.code_dir.insert((name, arity), idx);
+        self.code_dir.insert((name.clone(), arity), idx.clone());
     }
 
     fn use_qualified_module(

src/prolog/machine/toplevel.rs

@@ -81,11 +81,11 @@ impl<'a, 'b, 'c, R: Read> CompositeIndices<'a, 'b, 'c, R> {
         };
 
         if let Some(idx) = idx_opt {
-            self.local_code_dir().insert((name, arity), idx.clone());
+            self.local_code_dir().insert((name.clone(), arity), idx.clone());
             idx
         } else {
             let idx = CodeIndex::default();            
-            self.local_code_dir().insert((name, arity), idx.clone());
+            self.local_code_dir().insert((name.clone(), arity), idx.clone());
             idx
         }
     }
@@ -594,7 +594,7 @@ impl RelationWorker {
 
     fn fabricate_disjunct(&self, body_term: Term) -> (JumpStub, VecDeque<Term>) {
         let vars = self.compute_head(&body_term);
-        let clauses: Vec<_> = unfold_by_str(body_term, ";")
+        let results = unfold_by_str(body_term, ";")
             .into_iter()
             .map(|term| {
                 let mut subterms = unfold_by_str(term, ",");
@@ -603,13 +603,10 @@ impl RelationWorker {
                 check_for_internal_if_then(&mut subterms);
 
                 let term = subterms.pop().unwrap();
-                fold_by_str(subterms.into_iter(), term, clause_name!(","))
-            })
-            .collect();
+                let clause = fold_by_str(subterms.into_iter(), term, clause_name!(","));
 
-        let results = clauses
-            .into_iter()
-            .map(|clause| self.fabricate_rule_body(&vars, clause))
+                self.fabricate_rule_body(&vars, clause)
+            })
             .collect();
 
         (vars, results)