Rewrite SpecifiedValue as a read-only structure

app-proto/Cargo.toml

@@ -13,6 +13,7 @@ itertools = "0.13.0"
 js-sys = "0.3.70"
 lazy_static = "1.5.0"
 nalgebra = "0.33.0"
+readonly = "0.2.12"
 rustc-hash = "2.0.0"
 slab = "0.4.9"
 sycamore = "0.9.0-beta.3"

app-proto/src/assembly.rs

@@ -7,7 +7,7 @@ use web_sys::{console, wasm_bindgen::JsValue}; /* DEBUG */
 
 use crate::{
     engine::{Q, local_unif_to_std, realize_gram, ConfigSubspace, PartialMatrix},
-    specified::{SpecifiedValue, SpecifiedValue::{Absent, Present}}
+    specified::SpecifiedValue
 };
 
 // the types of the keys we use to access an assembly's elements and regulators
@@ -239,7 +239,7 @@ impl Assembly {
                 reps.0.dot(&(&*Q * reps.1))
             }
         );
-        let set_point = create_signal(Absent);
+        let set_point = create_signal(SpecifiedValue::from_empty_spec());
         self.insert_regulator(Regulator {
             subjects: subjects,
             measurement: measurement,
@@ -256,9 +256,9 @@ impl Assembly {
                     &JsValue::from(reg.subjects.0),
                     &JsValue::from(reg.subjects.1),
                     &JsValue::from(":"),
-                    &JsValue::from(reg.set_point.with_untracked(
+                    &reg.set_point.with_untracked(
-                        |set_pt| set_pt.spec()
+                        |set_pt| JsValue::from(set_pt.spec.as_str())
-                    ))
+                    )
                 );
             }
         });
@@ -269,7 +269,7 @@ impl Assembly {
             console::log_1(&JsValue::from(
                 format!("Updated constraint with subjects ({}, {})", subjects.0, subjects.1)
             ));
-            if set_point.with(|set_pt| matches!(set_pt, Present { .. })) {
+            if set_point.with(|set_pt| set_pt.is_present()) {
                 self.realize();
             }
         });
@@ -292,11 +292,11 @@ impl Assembly {
             self.regulators.with_untracked(|regs| {
                 for (_, reg) in regs {
                     reg.set_point.with_untracked(|set_pt| {
-                        if let Present { value, .. } = set_pt {
+                        if let Some(val) = set_pt.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);
+                            gram_to_be.push_sym(row, col, val);
                         }
                     });
                 }

app-proto/src/outline.rs

@@ -14,7 +14,7 @@ use crate::{
         Regulator,
         RegulatorKey
     },
-    specified::{SpecifiedValue, SpecifiedValue::{Absent, Present}}
+    specified::SpecifiedValue
 };
 
 // an editable view of a regulator
@@ -22,7 +22,7 @@ use crate::{
 fn RegulatorInput(regulator: Regulator) -> View {
     let valid = create_signal(true);
     let value = create_signal(
-        regulator.set_point.with_untracked(|set_pt| set_pt.spec())
+        regulator.set_point.with_untracked(|set_pt| set_pt.spec.clone())
     );
     
     // this closure resets the input value to the regulator's set point
@@ -30,7 +30,7 @@ fn RegulatorInput(regulator: Regulator) -> View {
     let reset_value = move || {
         batch(|| {
             valid.set(true);
-            value.set(regulator.set_point.with(|set_pt| set_pt.spec()));
+            value.set(regulator.set_point.with(|set_pt| set_pt.spec.clone()));
         })
     };
     
@@ -44,9 +44,10 @@ fn RegulatorInput(regulator: Regulator) -> View {
             class=move || {
                 if valid.get() {
                     regulator.set_point.with(|set_pt| {
-                        match set_pt {
+                        if set_pt.is_present() {
-                            Absent => "regulator-input",
+                            "regulator-input constraint"
-                            Present { .. } => "regulator-input constraint"
+                        } else {
+                            "regulator-input"
                         }
                     })
                 } else {

app-proto/src/specified.rs

@@ -1,48 +1,43 @@
 use std::num::ParseFloatError;
 
-// to construct a `SpecifiedValue` that might be `Present`, use the associated
+// a real number described by a specification string. since the structure is
-// function `try_from`. this ensures that `spec` is always a valid specification
+// read-only, we can guarantee that `spec` always specifies `value` in the
-// of `value` according to the format discussed at the implementation of
+// following format
-// `TryFrom<String>`
+//   ┌──────────────────────────────────────────────────────┬───────────┐
-pub enum SpecifiedValue {
+//   │ `spec`                                               │ `value`   │
-    Absent,
+//   ┝━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┿━━━━━━━━━━━┥
-    Present {
+//   │ a string that parses to the floating-point value `x` │ `Some(x)` │
-        spec: String,
+//   ├──────────────────────────────────────────────────────┼───────────┤
-        value: f64
+//   │ the empty string                                     │ `None`    │
-    }
+//   └──────────────────────────────────────────────────────┴───────────┘
+#[readonly::make]
+pub struct SpecifiedValue {
+    pub spec: String,
+    pub value: Option<f64>
 }
 
-use SpecifiedValue::{Absent, Present};
-
 impl SpecifiedValue {
-    // get the specification for this value. the associated function `try_from`
+    pub fn from_empty_spec() -> SpecifiedValue {
-    // is essentially a left inverse of this method:
+        SpecifiedValue { spec: String::new(), value: None }
-    //
+    }
-    //   SpecifiedValue::try_from(x.spec()) == Ok(x)
+    
-    //
+    pub fn is_present(&self) -> bool {
-    pub fn spec(&self) -> String {
+        matches!(self.value, Some(_))
-        match self {
-            Absent => String::new(),
-            Present { spec, .. } => spec.clone()
-        }
     }
 }
 
-// we can try to turn a specification string into a `SpecifiedValue`. if the
+// a `SpecifiedValue` can be constructed from a specification string, formatted
-// specification is empty, the `SpecifiedValue` is `Absent`. if the
+// as described in the comment on the structure definition. the result is `Ok`
-// specification parses to a floating-point value `x`, the `SpecifiedValue` is
+// if the specification is properly formatted, and `Error` if not
-// `Present`, with a `value` of `x`, and the specification is stored in `spec`.
-// these are currently 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)
+            Ok(SpecifiedValue { spec: spec, value: None })
         } else {
             spec.parse::<f64>().map(
-                |value| Present { spec: spec, value: value }
+                |value| SpecifiedValue { spec: spec, value: Some(value) }
             )
         }
     }