Add fields method to content (#1340)

docs/src/reference/types.md

@@ -604,6 +604,13 @@ field does not exist or fails with an error if no default value was specified.
   A default value to return if the field does not exist.
 - returns: any
 
+### fields()
+Return the fields of this content.
+
+```example
+#repr(rect(width: 10cm, height: 10cm).fields())
+```
+
 ### location()
 The location of the content. This is only available on content returned by
 [query]($func/query), for other content it will fail with an error. The

src/eval/methods.rs

@@ -81,6 +81,7 @@ pub fn call(
             "at" => content
                 .at(&args.expect::<EcoString>("field")?, args.named("default")?)
                 .at(span)?,
+            "fields" => Value::Dict(content.dict()),
             "location" => content
                 .location()
                 .ok_or("this method can only be called on content returned by query(..)")
@@ -332,7 +333,13 @@ pub fn methods_on(type_name: &str) -> &[(&'static str, bool)] {
             ("starts-with", true),
             ("trim", true),
         ],
-        "content" => &[("func", false), ("has", true), ("at", true), ("location", false)],
+        "content" => &[
+            ("func", false),
+            ("has", true),
+            ("at", true),
+            ("fields", false),
+            ("location", false),
+        ],
         "array" => &[
             ("all", true),
             ("any", true),

src/model/content.rs

@@ -12,7 +12,7 @@ use super::{
 };
 use crate::diag::{SourceResult, StrResult};
 use crate::doc::Meta;
-use crate::eval::{Cast, Str, Value, Vm};
+use crate::eval::{Cast, Dict, Str, Value, Vm};
 use crate::syntax::Span;
 use crate::util::pretty_array_like;
 
@@ -251,6 +251,13 @@ impl Content {
             .ok_or_else(|| missing_field_no_default(field))
     }
 
+    /// Return the fields of the content as a dict.
+    pub fn dict(&self) -> Dict {
+        self.fields()
+            .map(|(key, value)| (key.to_owned().into(), value))
+            .collect()
+    }
+
     /// The content's label.
     pub fn label(&self) -> Option<&Label> {
         match self.field_ref("label")? {

tests/typ/compiler/methods.typ

@@ -48,3 +48,8 @@
 ---
 // Error: 2-5 cannot mutate a constant: box
 #box.push(1)
+
+---
+// Test content fields method.
+#test([a].fields(), (text: "a"))
+#test([a *b*].fields(),  (children: ([a], [ ], strong[b])))