feat(event): Define Error event

Author: SersemPeca

src/lib.rs

@@ -23,6 +23,7 @@ mod tests {
         tracer.register_step(path, Line(2));
         tracer.register_special_event(EventLogKind::Write, "test");
         tracer.register_special_event(EventLogKind::Write, "test2");
+        tracer.register_special_event(EventLogKind::Error, "testError");
 
         let function_path_id = tracer.ensure_path_id(&path);
         let function_line = Line(3);
@@ -87,7 +88,7 @@ mod tests {
         tracer.register_return(NONE_VALUE);
         tracer.drop_variable("test_variable3");
 
-        assert_eq!(tracer.events.len(), 32);
+        assert_eq!(tracer.events.len(), 33);
         // visible with
         // cargo tets -- --nocapture
         // println!("{:#?}", tracer.events);

src/types.rs

@@ -6,6 +6,12 @@ use num_derive::FromPrimitive;
 use serde::{Deserialize, Serialize};
 use serde_repr::*;
 
+// currently, we do assume that we record the whole program
+// so, we try to include minimal amount of data,
+// as we can reconstruct some things like depth, id-s etc
+// afterwards in postprocessing
+// this assumption can change in the future
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub enum TraceLowLevelEvent {
     Step(StepRecord),
@@ -18,12 +24,17 @@ pub enum TraceLowLevelEvent {
     Call(CallRecord),
     Return(ReturnRecord),
     Event(RecordEvent),
+
+    // experimental modification value tracking events
     CompoundValue(CompoundValueRecord),
     CellValue(CellValueRecord),
     AssignCompoundItem(AssignCompoundItemRecord),
     AssignCell(AssignCellRecord),
     VariableCell(VariableCellRecord),
     DropVariable(VariableId),
+ 
+    // normal event, workaround for cases when we need to drop
+    // a step event, but the trace needs to be append-only
     DropLastStep,
 }
 
@@ -370,6 +381,7 @@ pub enum EventLogKind {
     CloseDir,
     Socket,
     Open,
+    Error,
     // used for trace events
     TraceLogEvent,
 }