Streamline value comparisons

1 files changed, 40 insertions, 6 deletions

diff --git a/src/eval/value.rs b/src/eval/value.rs
index 288e5ed7..84701b3d 100644
--- a/src/eval/value.rs
+++ b/src/eval/value.rs
@@ -1,4 +1,5 @@
 use std::any::Any;
+use std::cmp::Ordering;
 use std::collections::BTreeMap;
 use std::fmt::{self, Debug, Display, Formatter};
 use std::ops::Deref;
@@ -57,6 +58,14 @@ impl Value {
         Self::Template(vec![TemplateNode::Func(TemplateFunc::new(name, f))])
     }
 
+    /// Try to cast the value into a specific type.
+    pub fn cast<T>(self) -> CastResult<T, Self>
+    where
+        T: Cast<Value>,
+    {
+        T::cast(self)
+    }
+
     /// The name of the stored value's type.
     pub fn type_name(&self) -> &'static str {
         match self {
@@ -79,12 +88,37 @@ impl Value {
         }
     }
 
-    /// Try to cast the value into a specific type.
-    pub fn cast<T>(self) -> CastResult<T, Self>
-    where
-        T: Cast<Value>,
-    {
-        T::cast(self)
+    /// Recursively compute whether two values are equal.
+    pub fn eq(&self, rhs: &Self) -> bool {
+        match (self, rhs) {
+            (&Self::Int(a), &Self::Float(b)) => a as f64 == b,
+            (&Self::Float(a), &Self::Int(b)) => a == b as f64,
+            (&Self::Length(a), &Self::Linear(b)) => a == b.abs && b.rel.is_zero(),
+            (&Self::Relative(a), &Self::Linear(b)) => a == b.rel && b.abs.is_zero(),
+            (&Self::Linear(a), &Self::Length(b)) => a.abs == b && a.rel.is_zero(),
+            (&Self::Linear(a), &Self::Relative(b)) => a.rel == b && a.abs.is_zero(),
+            (Self::Array(a), Self::Array(b)) => {
+                a.len() == b.len() && a.iter().zip(b).all(|(x, y)| x.eq(y))
+            }
+            (Self::Dict(a), Self::Dict(b)) => {
+                a.len() == b.len()
+                    && a.iter().all(|(k, x)| b.get(k).map_or(false, |y| x.eq(y)))
+            }
+            (a, b) => a == b,
+        }
+    }
+
+    /// Compare a value with another value.
+    pub fn cmp(&self, rhs: &Self) -> Option<Ordering> {
+        match (self, rhs) {
+            (Self::Int(a), Self::Int(b)) => a.partial_cmp(b),
+            (Self::Int(a), Self::Float(b)) => (*a as f64).partial_cmp(b),
+            (Self::Float(a), Self::Int(b)) => a.partial_cmp(&(*b as f64)),
+            (Self::Float(a), Self::Float(b)) => a.partial_cmp(b),
+            (Self::Angle(a), Self::Angle(b)) => a.partial_cmp(b),
+            (Self::Length(a), Self::Length(b)) => a.partial_cmp(b),
+            _ => None,
+        }
     }
 }