From 715f9fb0a5b5242c405e2c9277596fad7509e0db Mon Sep 17 00:00:00 2001
From: Laurenz <laurmaedje@gmail.com>
Date: Tue, 4 Apr 2023 23:27:51 +0200
Subject: Locatable selectors

---
 library/src/meta/counter.rs | 23 ++++++++++-------------
 library/src/meta/query.rs   | 21 +++------------------
 library/src/prelude.rs      |  5 +++--
 3 files changed, 16 insertions(+), 33 deletions(-)

(limited to 'library/src')

diff --git a/library/src/meta/counter.rs b/library/src/meta/counter.rs
index 5ad9b48d..d771168d 100644
--- a/library/src/meta/counter.rs
+++ b/library/src/meta/counter.rs
@@ -276,10 +276,11 @@ use crate::prelude::*;
 pub fn counter(
     /// The key that identifies this counter.
     ///
-    /// - If this is the [`page`]($func/page) function, counts through pages.
-    /// - If this is any other element function, counts through its elements.
     /// - If it is a string, creates a custom counter that is only affected by
-    ///   manual updates.
+    ///   manual updates,
+    /// - If this is a `{<label>}`, counts through all elements with that label,
+    /// - If this is an element function or selector, counts through its elements,
+    /// - If this is the [`page`]($func/page) function, counts through pages.
     key: CounterKey,
 ) -> Value {
     Value::dynamic(Counter::new(key))
@@ -485,18 +486,14 @@ cast_from_value! {
     CounterKey,
     v: Str => Self::Str(v),
     label: Label => Self::Selector(Selector::Label(label)),
-    element: ElemFunc => {
-        if element == PageElem::func() {
-            return Ok(Self::Page);
-        }
-
-        if !Content::new(element).can::<dyn Locatable>() {
-            Err(eco_format!("cannot count through {}s", element.name()))?;
+    v: ElemFunc => {
+        if v == PageElem::func() {
+            Self::Page
+        } else {
+            Self::Selector(LocatableSelector::cast(Value::from(v))?.0)
         }
-
-        Self::Selector(Selector::Elem(element, None))
     },
-    selector: Selector => Self::Selector(selector),
+    selector: LocatableSelector => Self::Selector(selector.0),
 }
 
 impl Debug for CounterKey {
diff --git a/library/src/meta/query.rs b/library/src/meta/query.rs
index d4fab635..4241c19d 100644
--- a/library/src/meta/query.rs
+++ b/library/src/meta/query.rs
@@ -94,8 +94,8 @@ use crate::prelude::*;
 /// Returns: content
 #[func]
 pub fn query(
-    /// Can be an element function like a `heading` or `figure` or a
-    /// `{<label>}`.
+    /// Can be an element function like a `heading` or `figure`, a `{<label>}`
+    /// or a more complex selector like `{heading.where(level: 1)}`.
     ///
     /// Currently, only a subset of element functions is supported. Aside from
     /// headings and figures, this includes equations, references and all
@@ -104,7 +104,7 @@ pub fn query(
     /// have an explicit label attached to them. This limitation will be
     /// resolved
     /// in the future.
-    target: Target,
+    target: LocatableSelector,
 
     /// Can be any location. Why is it required then? As noted before, Typst has
     /// to evaluate parts of your code multiple times to determine the values of
@@ -151,18 +151,3 @@ pub fn query(
     };
     elements.into()
 }
-
-/// A query target.
-struct Target(Selector);
-
-cast_from_value! {
-    Target,
-    label: Label => Self(Selector::Label(label)),
-    element: ElemFunc => {
-        if !Content::new(element).can::<dyn Locatable>() {
-            Err(eco_format!("cannot query for {}s", element.name()))?;
-        }
-
-        Self(Selector::Elem(element, None))
-    }
-}
diff --git a/library/src/prelude.rs b/library/src/prelude.rs
index 4c83cf31..fc71e2c2 100644
--- a/library/src/prelude.rs
+++ b/library/src/prelude.rs
@@ -23,8 +23,9 @@ pub use typst::geom::*;
 #[doc(no_inline)]
 pub use typst::model::{
     element, Behave, Behaviour, Construct, Content, ElemFunc, Element, Finalize, Fold,
-    Introspector, Label, Locatable, Location, MetaElem, Resolve, Selector, Set, Show,
-    StabilityProvider, StyleChain, StyleVec, Styles, Synthesize, Unlabellable, Vt,
+    Introspector, Label, Locatable, LocatableSelector, Location, MetaElem, Resolve,
+    Selector, Set, Show, StabilityProvider, StyleChain, StyleVec, Styles, Synthesize,
+    Unlabellable, Vt,
 };
 #[doc(no_inline)]
 pub use typst::syntax::{Span, Spanned};
-- 
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