2 files changed, 26 insertions, 3 deletions
diff --git a/src/eval/scope.rs b/src/eval/scope.rs
index 20c18306..a3c9234b 100644
--- a/src/eval/scope.rs
+++ b/src/eval/scope.rs
@@ -1,10 +1,10 @@
 use std::cell::RefCell;
 use std::collections::HashMap;
-use std::fmt::{self, Debug, Formatter};
+use std::fmt::{self, Debug, Display, Formatter};
 use std::iter;
 use std::rc::Rc;
 
-use super::Value;
+use super::{AnyValue, EvalContext, FuncArgs, FuncValue, Type, Value};
 
 /// A slot where a variable is stored.
 pub type Slot = Rc<RefCell<Value>>;
@@ -100,6 +100,23 @@ impl Scope {
         self.values.insert(var.into(), Rc::new(cell));
     }
 
+    /// Define a constant function.
+    pub fn def_func<F>(&mut self, name: impl Into<String>, f: F)
+    where
+        F: Fn(&mut EvalContext, &mut FuncArgs) -> Value + 'static,
+    {
+        let name = name.into();
+        self.def_const(name.clone(), FuncValue::new(Some(name), f));
+    }
+
+    /// Define a constant variable with a value of variant `Value::Any`.
+    pub fn def_any<T>(&mut self, var: impl Into<String>, any: T)
+    where
+        T: Type + Debug + Display + Clone + PartialEq + 'static,
+    {
+        self.def_const(var, AnyValue::new(any))
+    }
+
     /// Define a mutable variable with a value.
     pub fn def_mut(&mut self, var: impl Into<String>, value: impl Into<Value>) {
         self.values.insert(var.into(), Rc::new(RefCell::new(value.into())));
diff --git a/src/eval/value.rs b/src/eval/value.rs
index a69398f0..0d87c28f 100644
--- a/src/eval/value.rs
+++ b/src/eval/value.rs
@@ -6,7 +6,7 @@ use std::ops::Deref;
 use std::rc::Rc;
 
 use super::{EvalContext, NodeMap};
-use crate::color::Color;
+use crate::color::{Color, RgbaColor};
 use crate::exec::ExecContext;
 use crate::geom::{Angle, Length, Linear, Relative};
 use crate::syntax::{Span, Spanned, Tree};
@@ -622,6 +622,12 @@ impl From<&str> for Value {
     }
 }
 
+impl From<RgbaColor> for Value {
+    fn from(v: RgbaColor) -> Self {
+        Self::Color(Color::Rgba(v))
+    }
+}
+
 impl From<AnyValue> for Value {
     fn from(v: AnyValue) -> Self {
         Self::Any(v)