Figures

2 files changed, 27 insertions, 13 deletions

diff --git a/src/eval/func.rs b/src/eval/func.rs
index 8da5c6bc..26854240 100644
--- a/src/eval/func.rs
+++ b/src/eval/func.rs
@@ -142,6 +142,14 @@ impl Func {
         self.select(Some(fields))
     }
 
+    /// The node id of this function if it is an element function.
+    pub fn id(&self) -> Option<NodeId> {
+        match **self.0 {
+            Repr::Node(id) => Some(id),
+            _ => None,
+        }
+    }
+
     /// Execute the function's set rule and return the resulting style map.
     pub fn set(&self, mut args: Args) -> SourceResult<StyleMap> {
         Ok(match &**self.0 {
@@ -156,16 +164,15 @@ impl Func {
 
     /// Create a selector for this function's node type.
     pub fn select(&self, fields: Option<Dict>) -> StrResult<Selector> {
-        match **self.0 {
-            Repr::Node(id) => {
-                if id == item!(text_id) {
-                    Err("to select text, please use a string or regex instead")?;
-                }
+        let Some(id) = self.id() else {
+            return Err("this function is not selectable".into());
+        };
 
-                Ok(Selector::Node(id, fields))
-            }
-            _ => Err("this function is not selectable")?,
+        if id == item!(text_id) {
+            Err("to select text, please use a string or regex instead")?;
         }
+
+        Ok(Selector::Node(id, fields))
     }
 }
 
@@ -196,10 +203,6 @@ impl From<NodeId> for Func {
     }
 }
 
-cast_to_value! {
-    v: NodeId => Value::Func(v.into())
-}
-
 /// A native Rust function.
 pub struct NativeFunc {
     /// The function's implementation.
diff --git a/src/model/content.rs b/src/model/content.rs
index be737331..012ad05f 100644
--- a/src/model/content.rs
+++ b/src/model/content.rs
@@ -10,7 +10,9 @@ use once_cell::sync::Lazy;
 
 use super::{node, Guard, Recipe, Style, StyleMap};
 use crate::diag::{SourceResult, StrResult};
-use crate::eval::{cast_from_value, Args, Cast, FuncInfo, Str, Value, Vm};
+use crate::eval::{
+    cast_from_value, cast_to_value, Args, Cast, Func, FuncInfo, Str, Value, Vm,
+};
 use crate::syntax::Span;
 use crate::util::pretty_array_like;
 use crate::World;
@@ -382,6 +384,15 @@ impl Deref for NodeId {
     }
 }
 
+cast_from_value! {
+    NodeId,
+    v: Func => v.id().ok_or("this function is not an element")?
+}
+
+cast_to_value! {
+    v: NodeId => Value::Func(v.into())
+}
+
 /// Static node for a node.
 pub struct NodeMeta {
     /// The node's name.