1 files changed, 27 insertions, 6 deletions

diff --git a/src/model/content.rs b/src/model/content.rs
index 17fa786b..be737331 100644
--- a/src/model/content.rs
+++ b/src/model/content.rs
@@ -10,7 +10,7 @@ use once_cell::sync::Lazy;
 
 use super::{node, Guard, Recipe, Style, StyleMap};
 use crate::diag::{SourceResult, StrResult};
-use crate::eval::{cast_from_value, Args, FuncInfo, Str, Value, Vm};
+use crate::eval::{cast_from_value, Args, Cast, FuncInfo, Str, Value, Vm};
 use crate::syntax::Span;
 use crate::util::pretty_array_like;
 use crate::World;
@@ -27,7 +27,7 @@ pub struct Content {
 /// Modifiers that can be attached to content.
 #[derive(Debug, Clone, PartialEq, Hash)]
 enum Modifier {
-    Prepared,
+    Synthesized,
     Guard(Guard),
 }
 
@@ -59,6 +59,12 @@ impl Content {
         self.id
     }
 
+    /// Whether the content is empty.
+    pub fn is_empty(&self) -> bool {
+        self.to::<SequenceNode>()
+            .map_or(false, |seq| seq.children().is_empty())
+    }
+
     /// Whether the contained node is of type `T`.
     pub fn is<T>(&self) -> bool
     where
@@ -112,6 +118,21 @@ impl Content {
             .map(|(_, value)| value)
     }
 
+    /// Access a field on the content as a specified type.
+    #[track_caller]
+    pub fn cast_field<T: Cast>(&self, name: &str) -> Option<T> {
+        match self.field(name) {
+            Some(value) => Some(value.clone().cast().unwrap()),
+            None => None,
+        }
+    }
+
+    /// Expect a field on the content to exist as a specified type.
+    #[track_caller]
+    pub fn expect_field<T: Cast>(&self, name: &str) -> T {
+        self.cast_field(name).unwrap()
+    }
+
     /// List all fields on the content.
     pub fn fields(&self) -> &[(EcoString, Value)] {
         &self.fields
@@ -209,14 +230,14 @@ impl Content {
     }
 
     /// Mark this content as prepared.
-    pub fn prepared(mut self) -> Self {
-        self.modifiers.push(Modifier::Prepared);
+    pub fn synthesized(mut self) -> Self {
+        self.modifiers.push(Modifier::Synthesized);
         self
     }
 
     /// Whether this node was prepared.
-    pub fn is_prepared(&self) -> bool {
-        self.modifiers.contains(&Modifier::Prepared)
+    pub fn is_synthesized(&self) -> bool {
+        self.modifiers.contains(&Modifier::Synthesized)
     }
 
     /// Whether no show rule was executed for this node so far.