allow substitution of variables

src/entity.rs

@@ -2,6 +2,7 @@ use std::cell::RefCell;
 use std::rc::Rc;
 
 use crate::math::{Point2, Region, Region1, Region2, Scalar};
+use crate::math::eqn::{Eqns};
 use std::fmt;
 
 #[derive(Clone, Copy, Debug)]
@@ -16,7 +17,7 @@ impl<T: Clone + fmt::Display, TRegion: Region<T> + fmt::Display> fmt::Display fo
     }
 }
 
-impl<T: Clone, TRegion: Region<T>> Var<T, TRegion> {
+impl<T: Clone, TRegion: Region<T> + Clone> Var<T, TRegion> {
     pub fn new(value: T, constraints: TRegion) -> Self {
         Self { value, constraints }
     }
@@ -33,6 +34,16 @@ impl<T: Clone, TRegion: Region<T>> Var<T, TRegion> {
         &self.value
     }
 
+    pub fn evaluate_with(&mut self, eqns: &Eqns) -> bool {
+        self.constraints = self.constraints.clone().evaluate_with(eqns).simplify();
+        if let Some(n) = self.constraints.nearest(&self.value) {
+            self.value = n;
+            true
+        } else {
+            false
+        }
+    }
+
     pub fn constraints(&self) -> &TRegion {
         &self.constraints
     }

src/main.rs

@@ -90,4 +90,11 @@ fn main() {
     } else {
         println!("All constraints have been solved")
     }
+    let e1 = eqn::Eqn::new(eqn::Expr::Unkn(u1), eqn::Expr::Const(1.));
+    let e2 = eqn::Eqn::new(eqn::Expr::Unkn(u2), eqn::Expr::Const(1.));
+    let eqns = eqn::Eqns(vec![e1, e2]);
+    for p in &mut points {
+        p.borrow_mut().pos.evaluate_with(&eqns);
+    }
+    print_points(&points);
 }

src/math/eqn.rs

@@ -588,7 +588,7 @@ impl fmt::Display for Eqn {
 }
 
 #[derive(Clone, Debug, PartialEq)]
-pub struct Eqns(Vec<Eqn>);
+pub struct Eqns(pub Vec<Eqn>);
 
 impl Unknowns for Eqns {
     fn unknowns(&self) -> UnknownSet {

src/math/mod.rs

@@ -21,10 +21,15 @@ pub type Value = eqn::Expr;
 
 // pub type Rot2 = nalgebra::UnitComplex<Value>;
 
-pub trait Region<T> {
+pub trait GenericRegion {
     fn full() -> Self;
+    fn intersection(self, other: Self) -> Self;
+    fn simplify(self) -> Self;
+    fn evaluate_with(self, eqns: &eqn::Eqns) -> Self;
+}
+
+pub trait Region<T>: GenericRegion {
     fn singleton(value: T) -> Self;
-    // fn intersection(self, other: Self) -> Self;
 
     fn nearest(&self, value: &T) -> Option<T>;
     fn contains(&self, value: &T) -> Option<bool>;
@@ -53,12 +58,16 @@ impl fmt::Display for Region1 {
     }
 }
 
-impl Region1 {
+impl GenericRegion for Region1 {
-    pub fn intersection(self, other: Region1) -> Self {
+    fn intersection(self, other: Region1) -> Self {
         Region1::Intersection(Box::new(self), Box::new(other))
     }
 
-    pub fn simplify(self) -> Self {
+    fn full() -> Self {
+        Region1::Full
+    }
+
+    fn simplify(self) -> Self {
         use Region1::*;
         match self {
             Singleton(n) => Singleton(n.simplify()),
@@ -67,13 +76,19 @@ impl Region1 {
             other => other,
         }
     }
-}
 
-impl Region<Scalar> for Region1 {
+    fn evaluate_with(self, eqns: &eqn::Eqns) -> Self {
-    fn full() -> Self {
+        use Region1::*;
-        Region1::Full
+        match self {
+            Singleton(n) => Singleton(n.evaluate_with(eqns)),
+            Range(l, u) => Range(l.evaluate_with(eqns), u.evaluate_with(eqns)),
+            Intersection(r1, r2) => r1.evaluate_with(eqns).intersection(r2.evaluate_with(eqns)),
+            other => other,
+        }
     }
+}
 
+impl Region<Scalar> for Region1 {
     fn singleton(value: Scalar) -> Self {
         Region1::Singleton(value.into())
     }
@@ -230,6 +245,14 @@ impl Line2 {
         }
         Region2::Line(new_l)
     }
+
+    pub fn evaluate_with(self, eqns: &eqn::Eqns) -> Self {
+        Line2 {
+            start: self.start.evaluate_with(eqns),
+            dir: self.dir,
+            extent: self.extent.evaluate_with(eqns),
+        }
+    }
 }
 
 #[derive(Clone, Debug)]
@@ -257,11 +280,42 @@ impl fmt::Display for Region2 {
     }
 }
 
-impl Region<Point2<Scalar>> for Region2 {
+impl GenericRegion for Region2 {
     fn full() -> Self {
         Region2::Full
     }
 
+    fn intersection(self, other: Self) -> Self {
+        use Region2::*;
+        match (self, other) {
+            (Empty, _) | (_, Empty) => Empty,
+            (Full, r) | (r, Full) => r,
+            (r1, r2) => Intersection(Box::new(r1), Box::new(r2)),
+        }
+    }
+
+    fn simplify(self) -> Region2 {
+        use Region2::*;
+        match self {
+            Singleton(n) => Singleton(n.simplify()),
+            Line(l) => l.simplify(),
+            Intersection(r1, r2) => r1.simplify().intersect(r2.simplify()),
+            other => other,
+        }
+    }
+
+    fn evaluate_with(self, eqns: &eqn::Eqns) -> Self {
+        use Region2::*;
+        match self {
+            Singleton(n) => Singleton(n.evaluate_with(eqns)),
+            Line(l) => Line(l.evaluate_with(eqns)),
+            Intersection(r1, r2) => r1.evaluate_with(eqns).intersection(r2.evaluate_with(eqns)),
+            other => other,
+        }
+    }
+}
+
+impl Region<Point2<Scalar>> for Region2 {
     fn singleton(value: Point2<Scalar>) -> Self {
         Region2::Singleton(value.into())
     }
@@ -312,10 +366,6 @@ impl Region<Point2<Scalar>> for Region2 {
 }
 
 impl Region<Point2<Value>> for Region2 {
-    fn full() -> Self {
-        Region2::Full
-    }
-
     fn singleton(value: Point2<Value>) -> Self {
         Region2::Singleton(value)
     }
@@ -353,15 +403,6 @@ impl Region<Point2<Value>> for Region2 {
 }
 
 impl Region2 {
-    pub fn intersection(self, other: Self) -> Self {
-        use Region2::*;
-        match (self, other) {
-            (Empty, _) | (_, Empty) => Empty,
-            (Full, r) | (r, Full) => r,
-            (r1, r2) => Intersection(Box::new(r1), Box::new(r2)),
-        }
-    }
-
     /*
     pub fn union(r1: Region2, r2: Region2) -> Region2 {
         use Region2::*;
@@ -402,14 +443,4 @@ impl Region2 {
             (r1, r2) => Intersection(Box::new(r1), Box::new(r2)),
         }
     }
-
-    pub fn simplify(self) -> Region2 {
-        use Region2::*;
-        match self {
-            Singleton(n) => Singleton(n.simplify()),
-            Line(l) => l.simplify(),
-            Intersection(r1, r2) => r1.simplify().intersect(r2.simplify()),
-            other => other,
-        }
-    }
 }

src/math/vec.rs

@@ -1,4 +1,5 @@
 use super::{Scalar, Value};
+use super::eqn::Eqns;
 
 use std::ops;
 
@@ -92,8 +93,15 @@ impl<T> Point2<T> {
 impl Point2<Value> {
   pub fn simplify(self) -> Self {
     Self {
-      x: self.x.distribute().simplify().distribute().simplify(),
+      x: self.x.distribute().simplify(),
-      y: self.y.distribute().simplify().distribute().simplify(),
+      y: self.y.distribute().simplify(),
+    }
+  }
+
+  pub fn evaluate_with(self, eqns: &Eqns) -> Self {
+    Self {
+      x: self.x.evaluate_with(eqns),
+      y: self.y.evaluate_with(eqns),
     }
   }
 }

src/relation.rs

@@ -1,5 +1,5 @@
 use crate::entity::{Point as PointEntity, PointRef};
-use crate::math::{Line2, Vec2, Point2, Region1, Region2, Rot2, Scalar, Value, Region};
+use crate::math::{Line2, Vec2, Point2, Region1, Region2, Rot2, Scalar, Value, GenericRegion};
 
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub enum ResolveResult {