Target-specific native show rules (#6569)

3 files changed, 21 insertions, 44 deletions

diff --git a/crates/typst-library/src/introspection/counter.rs b/crates/typst-library/src/introspection/counter.rs
index a7925e13..b3c52de4 100644
--- a/crates/typst-library/src/introspection/counter.rs
+++ b/crates/typst-library/src/introspection/counter.rs
@@ -12,7 +12,7 @@ use crate::engine::{Engine, Route, Sink, Traced};
 use crate::foundations::{
     cast, elem, func, scope, select_where, ty, Args, Array, Construct, Content, Context,
     Element, Func, IntoValue, Label, LocatableSelector, NativeElement, Packed, Repr,
-    Selector, Show, Smart, Str, StyleChain, Value,
+    Selector, ShowFn, Smart, Str, StyleChain, Value,
 };
 use crate::introspection::{Introspector, Locatable, Location, Tag};
 use crate::layout::{Frame, FrameItem, PageElem};
@@ -683,8 +683,8 @@ cast! {
 }
 
 /// Executes an update of a counter.
-#[elem(Construct, Locatable, Show, Count)]
-struct CounterUpdateElem {
+#[elem(Construct, Locatable, Count)]
+pub struct CounterUpdateElem {
     /// The key that identifies the counter.
     #[required]
     key: CounterKey,
@@ -701,12 +701,6 @@ impl Construct for CounterUpdateElem {
     }
 }
 
-impl Show for Packed<CounterUpdateElem> {
-    fn show(&self, _: &mut Engine, _: StyleChain) -> SourceResult<Content> {
-        Ok(Content::empty())
-    }
-}
-
 impl Count for Packed<CounterUpdateElem> {
     fn update(&self) -> Option<CounterUpdate> {
         Some(self.update.clone())
@@ -714,7 +708,7 @@ impl Count for Packed<CounterUpdateElem> {
 }
 
 /// Executes a display of a counter.
-#[elem(Construct, Locatable, Show)]
+#[elem(Construct, Locatable)]
 pub struct CounterDisplayElem {
     /// The counter.
     #[required]
@@ -738,20 +732,18 @@ impl Construct for CounterDisplayElem {
     }
 }
 
-impl Show for Packed<CounterDisplayElem> {
-    fn show(&self, engine: &mut Engine, styles: StyleChain) -> SourceResult<Content> {
-        Ok(self
-            .counter
-            .display_impl(
-                engine,
-                self.location().unwrap(),
-                self.numbering.clone(),
-                self.both,
-                Some(styles),
-            )?
-            .display())
-    }
-}
+pub const COUNTER_DISPLAY_RULE: ShowFn<CounterDisplayElem> = |elem, engine, styles| {
+    Ok(elem
+        .counter
+        .display_impl(
+            engine,
+            elem.location().unwrap(),
+            elem.numbering.clone(),
+            elem.both,
+            Some(styles),
+        )?
+        .display())
+};
 
 /// An specialized handler of the page counter that tracks both the physical
 /// and the logical page counter.
diff --git a/crates/typst-library/src/introspection/metadata.rs b/crates/typst-library/src/introspection/metadata.rs
index 06000174..8ad74b96 100644
--- a/crates/typst-library/src/introspection/metadata.rs
+++ b/crates/typst-library/src/introspection/metadata.rs
@@ -1,6 +1,4 @@
-use crate::diag::SourceResult;
-use crate::engine::Engine;
-use crate::foundations::{elem, Content, Packed, Show, StyleChain, Value};
+use crate::foundations::{elem, Value};
 use crate::introspection::Locatable;
 
 /// Exposes a value to the query system without producing visible content.
@@ -24,15 +22,9 @@ use crate::introspection::Locatable;
 ///   query(<note>).first().value
 /// }
 /// ```
-#[elem(Show, Locatable)]
+#[elem(Locatable)]
 pub struct MetadataElem {
     /// The value to embed into the document.
     #[required]
     pub value: Value,
 }
-
-impl Show for Packed<MetadataElem> {
-    fn show(&self, _: &mut Engine, _styles: StyleChain) -> SourceResult<Content> {
-        Ok(Content::empty())
-    }
-}
diff --git a/crates/typst-library/src/introspection/state.rs b/crates/typst-library/src/introspection/state.rs
index 784f2acb..2d15a5de 100644
--- a/crates/typst-library/src/introspection/state.rs
+++ b/crates/typst-library/src/introspection/state.rs
@@ -6,8 +6,7 @@ use crate::diag::{bail, At, SourceResult};
 use crate::engine::{Engine, Route, Sink, Traced};
 use crate::foundations::{
     cast, elem, func, scope, select_where, ty, Args, Construct, Content, Context, Func,
-    LocatableSelector, NativeElement, Packed, Repr, Selector, Show, Str, StyleChain,
-    Value,
+    LocatableSelector, NativeElement, Repr, Selector, Str, Value,
 };
 use crate::introspection::{Introspector, Locatable, Location};
 use crate::routines::Routines;
@@ -372,8 +371,8 @@ cast! {
 }
 
 /// Executes a display of a state.
-#[elem(Construct, Locatable, Show)]
-struct StateUpdateElem {
+#[elem(Construct, Locatable)]
+pub struct StateUpdateElem {
     /// The key that identifies the state.
     #[required]
     key: Str,
@@ -389,9 +388,3 @@ impl Construct for StateUpdateElem {
         bail!(args.span, "cannot be constructed manually");
     }
 }
-
-impl Show for Packed<StateUpdateElem> {
-    fn show(&self, _: &mut Engine, _: StyleChain) -> SourceResult<Content> {
-        Ok(Content::empty())
-    }
-}