app-proto/src/assembly.rs

@@ -1,7 +1,11 @@
 use nalgebra::{DMatrix, DVector, DVectorView, Vector3};
 use rustc_hash::FxHashMap;
 use slab::Slab;
-use std::{collections::BTreeSet, sync::atomic::{AtomicU64, Ordering}};
+use std::{
+    collections::BTreeSet,
+    num::ParseFloatError,
+    sync::atomic::{AtomicU64, Ordering}
+};
 use sycamore::prelude::*;
 use web_sys::{console, wasm_bindgen::JsValue}; /* DEBUG */
 
@@ -111,41 +115,75 @@ impl Element {
     }
 }
 
-// `set_point_spec` is always a valid specification of `set_point`
-//   ┌────────────┬─────────────────────────────────────────────────────┐
-//   │`set_point` │ `set_point_spec`                                    │
-//   ┝━━━━━━━━━━━━┿━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┥
-//   │`Some(x)`   │ a string that parses to the floating-point value `x`│
-//   ├────────────┼─────────────────────────────────────────────────────┤
-//   │`None`      │ the empty string                                    │
-//   └────────────┴─────────────────────────────────────────────────────┘
+// to construct a `SpecifiedValue` that might be `Present`, use the associated
+// function `try_from`. this ensures that `spec` is always a valid specification
+// of `value` according to the format discussed above the implementation of
+// `TryFrom<String>`
+pub enum SpecifiedValue {
+    Absent,
+    Present {
+        spec: String,
+        value: f64
+    }
+}
+
+use SpecifiedValue::*;
+
+impl SpecifiedValue {
+    // get the specification for this value. the associated function `try_from`
+    // is essentially a left inverse of this method:
+    //
+    //   SpecifiedValue::try_from(x.spec()) == Ok(x)
+    //
+    pub fn spec(&self) -> String {
+        match self {
+            Absent => String::new(),
+            Present { spec, .. } => spec.clone()
+        }
+    }
+    
+    fn is_present(&self) -> bool {
+        match self {
+            Absent => false,
+            Present { .. } => true
+        }
+    }
+}
+
+// we can try to turn a specification string into a `SpecifiedValue`. if the
+// specification is empty, the `SpecifiedValue` is `Absent`. if the
+// specification parses to a floating-point value `x`, the `SpecifiedValue` is
+// `Present`, with a `value` of `x`, and the specification is stored in `spec`.
+// these are the only valid specifications; any other produces an error
+impl TryFrom<String> for SpecifiedValue {
+    type Error = ParseFloatError;
+    
+    fn try_from(spec: String) -> Result<Self, Self::Error> {
+        if spec.is_empty() {
+            Ok(Absent)
+        } else {
+            spec.parse::<f64>().map(
+                |value| Present { spec: spec, value: value }
+            )
+        }
+    }
+}
+
 #[derive(Clone, Copy)]
 pub struct Regulator {
     pub subjects: (ElementKey, ElementKey),
     pub measurement: ReadSignal<f64>,
-    pub set_point: ReadSignal<Option<f64>>,
-    
-    set_point_writable: Signal<Option<f64>>,
-    set_point_spec: Signal<String>
+    pub set_point: Signal<SpecifiedValue>
 }
 
 impl Regulator {
-    pub fn get_set_point_spec_clone(&self) -> String {
-        self.set_point_spec.get_clone()
-    }
-    
-    pub fn get_set_point_spec_clone_untracked(&self) -> String {
-        self.set_point_spec.get_clone_untracked()
-    }
-    
-    pub fn try_specify_set_point(&self, spec: String) -> bool {
-        match spec.parse::<f64>() {
-            Err(_) if !spec.is_empty() => false,
-            set_pt => {
-                self.set_point_writable.set(set_pt.ok());
-                self.set_point_spec.set(spec);
+    pub fn try_set(&self, set_pt_spec: String) -> bool {
+        match SpecifiedValue::try_from(set_pt_spec) {
+            Ok(set_pt) => {
+                self.set_point.set(set_pt);
                 true
             }
+            Err(_) => false,
         }
     }
 }
@@ -255,18 +293,15 @@ impl Assembly {
                 reps.0.dot(&(&*Q * reps.1))
             }
         );
-        let set_point_writable = create_signal(None);
-        let set_point = *set_point_writable;
+        let set_point = create_signal(Absent);
         self.insert_regulator(Regulator {
             subjects: subjects,
             measurement: measurement,
-            set_point: set_point,
-            set_point_writable: set_point_writable,
-            set_point_spec: create_signal(String::new())
+            set_point: set_point
         });
         
         /* DEBUG */
-        // print updated regulator list
+        // print an updated list of regulators
         console::log_1(&JsValue::from("Regulators:"));
         self.regulators.with(|regs| {
             for (_, reg) in regs.into_iter() {
@@ -275,7 +310,9 @@ impl Assembly {
                     &JsValue::from(reg.subjects.0),
                     &JsValue::from(reg.subjects.1),
                     &JsValue::from(":"),
-                    &JsValue::from(reg.set_point.get_untracked())
+                    &JsValue::from(reg.set_point.with_untracked(
+                        |set_pt| set_pt.spec()
+                    ))
                 );
             }
         });
@@ -286,7 +323,7 @@ impl Assembly {
             console::log_1(&JsValue::from(
                 format!("Updated constraint with subjects ({}, {})", subjects.0, subjects.1)
             ));
-            if set_point.with(|set_pt| set_pt.is_some()) {
+            if set_point.with(|set_pt| set_pt.is_present()) {
                 self.realize();
             }
         });
@@ -308,15 +345,17 @@ impl Assembly {
             let mut gram_to_be = PartialMatrix::new();
             self.regulators.with_untracked(|regs| {
                 for (_, reg) in regs {
-                    match reg.set_point.get_untracked() {
-                        Some(set_pt) => {
-                            let subjects = reg.subjects;
-                            let row = elts[subjects.0].column_index.unwrap();
-                            let col = elts[subjects.1].column_index.unwrap();
-                            gram_to_be.push_sym(row, col, set_pt);
-                        },
-                        None => ()
-                    }
+                    reg.set_point.with_untracked(|set_pt| {
+                        match set_pt {
+                            Absent => (),
+                            Present { value, .. } => {
+                                let subjects = reg.subjects;
+                                let row = elts[subjects.0].column_index.unwrap();
+                                let col = elts[subjects.1].column_index.unwrap();
+                                gram_to_be.push_sym(row, col, *value);
+                            }
+                        };
+                    });
                 }
             });
             

app-proto/src/outline.rs

@@ -10,9 +10,10 @@ use crate::{
     AppState,
     assembly,
     assembly::{
+        ElementKey,
         Regulator,
         RegulatorKey,
-        ElementKey
+        SpecifiedValue::*
     }
 };
 
@@ -20,14 +21,16 @@ use crate::{
 #[component(inline_props)]
 fn RegulatorInput(regulator: Regulator) -> View {
     let valid = create_signal(true);
-    let value = create_signal(regulator.get_set_point_spec_clone_untracked());
+    let value = create_signal(
+        regulator.set_point.with_untracked(|set_pt| set_pt.spec())
+    );
     
     // this closure resets the input value to the regulator's set point
-    // specification, which is always a valid specification
+    // specification
     let reset_value = move || {
         batch(|| {
             valid.set(true);
-            value.set(regulator.get_set_point_spec_clone());
+            value.set(regulator.set_point.with(|set_pt| set_pt.spec()));
         })
     };
     
@@ -40,10 +43,12 @@ fn RegulatorInput(regulator: Regulator) -> View {
             r#type="text",
             class=move || {
                 if valid.get() {
-                    match regulator.set_point.get() {
-                        Some(_) => "regulator-input constraint",
-                        None => "regulator-input"
-                    }
+                    regulator.set_point.with(|set_pt| {
+                        match set_pt {
+                            Absent => "regulator-input",
+                            Present { .. } => "regulator-input constraint"
+                        }
+                    })
                 } else {
                     "regulator-input invalid"
                 }
@@ -51,7 +56,7 @@ fn RegulatorInput(regulator: Regulator) -> View {
             placeholder=regulator.measurement.with(|result| result.to_string()),
             bind:value=value,
             on:change=move |_| valid.set(
-                regulator.try_specify_set_point(value.get_clone_untracked())
+                regulator.try_set(value.get_clone_untracked())
             ),
             on:keydown={
                 move |event: KeyboardEvent| {