feat: add DropVariable event, rename some variable-related api-s

rename the Variable event to VariableName;
register_variable_event to register_variable_name

register_variable_cell to register_variable

this makes it possible to register variables at certain points
and drop them at the end of scope/calls, like Stan imagined before

it shouldn't contradict or stop the original mechanism from working:
which should be able to register explicitly variables with full values
wherever it's needed hopefully

Author: alehander92

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "runtime_tracing"
-version = "0.5.14-experimental-4"
+version = "0.5.14-experimental-5"
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

src/lib.rs

@@ -74,14 +74,15 @@ mod tests {
                 type_id,
             },
         );
-        tracer.register_variable_cell("test_variable3", ValueId(1));
+        tracer.register_variable("test_variable3", ValueId(1));
         tracer.assign_cell(ValueId(1), int_value_2.clone());
         tracer.register_cell_value(ValueId(2), int_value_2.clone());
         tracer.assign_compound_item(ValueId(0), 0, ValueId(2));
 
         tracer.register_return(NONE_VALUE);
+        tracer.drop_variable("test_variable3");
 
-        assert_eq!(tracer.events.len(), 31);
+        assert_eq!(tracer.events.len(), 32);
         // visible with
         // cargo tets -- --nocapture
         // println!("{:#?}", tracer.events);

src/tracer.rs

@@ -97,7 +97,7 @@ impl Tracer {
     pub fn ensure_variable_id(&mut self, variable_name: &str) -> VariableId {
         if !self.variables.contains_key(variable_name) {
             self.variables.insert(variable_name.to_string(), VariableId(self.variables.len()));
-            self.register_variable_event(variable_name);
+            self.register_variable_name(variable_name);
         }
         *self.variables.get(variable_name).unwrap()
     }
@@ -170,8 +170,8 @@ impl Tracer {
         self.register_full_value(variable_id, value);
     }
 
-    pub fn register_variable_event(&mut self, variable_name: &str) {
-        self.events.push(TraceLowLevelEvent::Variable(variable_name.to_string()));
+    pub fn register_variable_name(&mut self, variable_name: &str) {
+        self.events.push(TraceLowLevelEvent::VariableName(variable_name.to_string()));
     }
 
     pub fn register_full_value(&mut self, variable_id: VariableId, value: ValueRecord) {
@@ -198,12 +198,17 @@ impl Tracer {
         self.events.push(TraceLowLevelEvent::AssignCell(AssignCellRecord { value_id, new_value }));
     }
 
-    pub fn register_variable_cell(&mut self, variable_name: &str, value_id: ValueId) {
+    pub fn register_variable(&mut self, variable_name: &str, value_id: ValueId) {
         let variable_id = self.ensure_variable_id(variable_name);
         self.events
             .push(TraceLowLevelEvent::VariableCell(VariableCellRecord { variable_id, value_id }));
     }
 
+    pub fn drop_variable(&mut self, variable_name: &str) {
+        let variable_id = self.ensure_variable_id(variable_name);
+        self.events.push(TraceLowLevelEvent::DropVariable(variable_id));
+    }
+
     pub fn drop_last_step(&mut self) {
         self.events.push(TraceLowLevelEvent::DropLastStep);
     }

src/types.rs

@@ -10,7 +10,7 @@ use serde_repr::*;
 pub enum TraceLowLevelEvent {
     Step(StepRecord),
     Path(PathBuf),            // should be always generated before usage, so we can stop stream at random n
-    Variable(String),         // interning new name for it
+    VariableName(String),     // interning new name for it
     Type(TypeRecord),         // should be always generated before Value referencing it
     Value(FullValueRecord),   // full values: simpler case working even without modification support
     Function(FunctionRecord), // should be always generated before CallRecord referencing it
@@ -22,6 +22,7 @@ pub enum TraceLowLevelEvent {
     AssignCompoundItem(AssignCompoundItemRecord),
     AssignCell(AssignCellRecord),
     VariableCell(VariableCellRecord),
+    DropVariable(VariableId),
     DropLastStep,
 }