From 5506ec1f43bdeceb995af792200600e703823272 Mon Sep 17 00:00:00 2001
From: Aaron Fenyes <aaron.fenyes@fareycircles.ooo>
Date: Thu, 17 Apr 2025 21:25:22 -0700
Subject: [PATCH] Make regulator activation less redundant

---
 app-proto/src/assembly.rs | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/app-proto/src/assembly.rs b/app-proto/src/assembly.rs
index 1850771..68a2863 100644
--- a/app-proto/src/assembly.rs
+++ b/app-proto/src/assembly.rs
@@ -148,7 +148,15 @@ pub trait Regulator: ProblemPoser + OutlineItem {
     fn measurement(&self) -> ReadSignal<f64>;
     fn set_point(&self) -> Signal<SpecifiedValue>;
     
-    fn activate(&self, _assembly: &Assembly) {}
+    // this method is used to responsively precondition the assembly for
+    // realization when the regulator becomes a constraint, or is edited while
+    // acting as a constraint. it should track the set point, do any desired
+    // preconditioning when the set point is present, and use its return value
+    // to report whether the set is present. the default implementation does no
+    // preconditioning
+    fn try_activate(&self, _assembly: &Assembly) -> bool {
+        self.set_point().with(|set_pt| set_pt.is_present())
+    }
 }
 
 pub struct InversiveDistanceRegulator {
@@ -240,14 +248,18 @@ impl Regulator for HalfCurvatureRegulator {
         self.set_point
     }
     
-    fn activate(&self, assembly: &Assembly) {
-        if let Some(half_curv) = self.set_point.with_untracked(|set_pt| set_pt.value) {
-            let representation = assembly.elements.with_untracked(
-                |elts| elts[self.subject].representation
-            );
-            representation.update(
-                |rep| change_half_curvature(rep, half_curv)
-            );
+    fn try_activate(&self, assembly: &Assembly) -> bool {
+        match self.set_point.with(|set_pt| set_pt.value) {
+            Some(half_curv) => {
+                let representation = assembly.elements.with_untracked(
+                    |elts| elts[self.subject].representation
+                );
+                representation.update(
+                    |rep| change_half_curvature(rep, half_curv)
+                );
+                true
+            }
+            None => false
         }
     }
 }
@@ -382,8 +394,7 @@ impl Assembly {
             console::log_1(&JsValue::from(
                 format!("Updated regulator with subjects {:?}", regulator_rc.subjects())
             ));
-            if regulator_rc.set_point().with(|set_pt| set_pt.is_present()) {
-                regulator_rc.activate(&self_for_effect);
+            if regulator_rc.try_activate(&self_for_effect) {
                 self_for_effect.realize();
             }
         });