feat: Implement efficient node lookup table using node indices (microsoft#463)

Major Changes:
- Add generic Lookup<T> structure for efficient O(1) module-level data access
- Combine separate scope and order lookups into unified QuerySchedule structure
- Add query_schedule field to Interpreter for dedicated user query scheduling
- Refactor loop hoising to separate module
- Use efficient lookup for loop vars
- Also added more tests for loops

Key Concept:
- Ensure module context and indexing stay synchronized during function calls

Testing:
- All scheduler and interpreter tests passing

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

Author: anakrish

src/engine.rs

@@ -737,28 +737,13 @@ impl Engine {
         self.interpreter.clean_internal_evaluation_state();
 
         self.interpreter.create_rule_prefixes()?;
-        let query_module = {
-            let source = Source::from_contents(
-                "<query_module.rego>".to_owned(),
-                "package __internal_query_module".to_owned(),
-            )?;
-            Ref::new(Parser::new(&source)?.parse()?)
-        };
-
-        // Parse the query.
-        let query_source = Source::from_contents("<query.rego>".to_string(), query)?;
-        let mut parser = self.make_parser(&query_source)?;
-        let query_node = parser.parse_user_query()?;
+        let (query_module, query_node, query_schedule) = self.make_query(query)?;
         if query_node.span.text() == "data" {
             self.eval_modules(enable_tracing)?;
         }
-        let query_schedule = Analyzer::new().analyze_query_snippet(&self.modules, &query_node)?;
-        self.interpreter.eval_user_query(
-            &query_module,
-            &query_node,
-            &query_schedule,
-            enable_tracing,
-        )
+
+        self.interpreter
+            .eval_user_query(&query_module, &query_node, query_schedule, enable_tracing)
     }
 
     /// Evaluate a Rego query that produces a boolean value.
@@ -843,36 +828,41 @@ impl Engine {
         !matches!(self.eval_bool_query(query, enable_tracing), Ok(false))
     }
 
-    #[doc(hidden)]
-    /// Evaluate the given query and all the rules in the supplied policies.
-    ///
-    /// This is mainly used for testing Regorus itself.
-    pub fn eval_query_and_all_rules(
-        &mut self,
-        query: String,
-        enable_tracing: bool,
-    ) -> Result<QueryResults> {
-        self.eval_modules(enable_tracing)?;
-
-        let query_module = {
+    fn make_query(&mut self, query: String) -> Result<(NodeRef<Module>, NodeRef<Query>, Schedule)> {
+        let mut query_module = {
             let source = Source::from_contents(
                 "<query_module.rego>".to_owned(),
                 "package __internal_query_module".to_owned(),
             )?;
-            Ref::new(Parser::new(&source)?.parse()?)
+            Parser::new(&source)?.parse()?
         };
 
         // Parse the query.
         let query_source = Source::from_contents("<query.rego>".to_string(), query)?;
         let mut parser = self.make_parser(&query_source)?;
         let query_node = parser.parse_user_query()?;
+        query_module.num_expressions = parser.num_expressions();
+        query_module.num_queries = parser.num_queries();
+        query_module.num_statements = parser.num_statements();
         let query_schedule = Analyzer::new().analyze_query_snippet(&self.modules, &query_node)?;
-        self.interpreter.eval_user_query(
-            &query_module,
-            &query_node,
-            &query_schedule,
-            enable_tracing,
-        )
+
+        Ok((Ref::new(query_module), query_node, query_schedule))
+    }
+
+    #[doc(hidden)]
+    /// Evaluate the given query and all the rules in the supplied policies.
+    ///
+    /// This is mainly used for testing Regorus itself.
+    pub fn eval_query_and_all_rules(
+        &mut self,
+        query: String,
+        enable_tracing: bool,
+    ) -> Result<QueryResults> {
+        self.eval_modules(enable_tracing)?;
+
+        let (query_module, query_node, query_schedule) = self.make_query(query)?;
+        self.interpreter
+            .eval_user_query(&query_module, &query_node, query_schedule, enable_tracing)
     }
 
     #[doc(hidden)]