XML reading

3 files changed, 50 insertions, 2 deletions

diff --git a/src/library/mod.rs b/src/library/mod.rs
index d806f298..91e4671c 100644
--- a/src/library/mod.rs
+++ b/src/library/mod.rs
@@ -98,6 +98,7 @@ pub fn new() -> Scope {
     std.def_fn("lorem", utility::lorem);
     std.def_fn("csv", utility::csv);
     std.def_fn("json", utility::json);
+    std.def_fn("xml", utility::xml);
 
     // Predefined colors.
     std.define("black", Color::BLACK);
diff --git a/src/library/prelude.rs b/src/library/prelude.rs
index 44d1af7f..03bef51e 100644
--- a/src/library/prelude.rs
+++ b/src/library/prelude.rs
@@ -9,10 +9,12 @@ pub use std::sync::Arc;
 pub use comemo::Tracked;
 pub use typst_macros::node;
 
-pub use crate::diag::{with_alternative, At, SourceError, SourceResult, StrResult};
+pub use crate::diag::{
+    with_alternative, At, FileError, FileResult, SourceError, SourceResult, StrResult,
+};
 pub use crate::eval::{
     Arg, Args, Array, Cast, Dict, Dynamic, Func, Node, RawAlign, RawLength, RawStroke,
-    Scope, Smart, Value, Vm,
+    Scope, Smart, Str, Value, Vm,
 };
 pub use crate::frame::*;
 pub use crate::geom::*;
diff --git a/src/library/utility/data.rs b/src/library/utility/data.rs
index e3efe6e7..0cff42c1 100644
--- a/src/library/utility/data.rs
+++ b/src/library/utility/data.rs
@@ -1,5 +1,6 @@
 use std::fmt::Write;
 
+use crate::diag::format_xml_like_error;
 use crate::library::prelude::*;
 
 /// Read structured data from a CSV file.
@@ -84,3 +85,47 @@ fn format_json_error(error: serde_json::Error) -> String {
         error.line()
     )
 }
+
+/// Read structured data from an XML file.
+pub fn xml(vm: &mut Vm, args: &mut Args) -> SourceResult<Value> {
+    let Spanned { v: path, span } =
+        args.expect::<Spanned<EcoString>>("path to xml file")?;
+
+    let path = vm.locate(&path).at(span)?;
+    let data = vm.world.file(&path).at(span)?;
+    let text = std::str::from_utf8(&data).map_err(FileError::from).at(span)?;
+
+    let document = roxmltree::Document::parse(text).map_err(format_xml_error).at(span)?;
+
+    Ok(convert_xml(document.root()))
+}
+
+/// Convert an XML node to a Typst value.
+fn convert_xml(node: roxmltree::Node) -> Value {
+    if node.is_text() {
+        return Value::Str(node.text().unwrap_or_default().into());
+    }
+
+    let children: Array = node.children().map(convert_xml).collect();
+    if node.is_root() {
+        return Value::Array(children);
+    }
+
+    let tag: Str = node.tag_name().name().into();
+    let attrs: Dict = node
+        .attributes()
+        .iter()
+        .map(|attr| (attr.name().into(), attr.value().into()))
+        .collect();
+
+    Value::Dict(dict! {
+        "tag" => tag,
+        "attrs" => attrs,
+        "children" => children,
+    })
+}
+
+/// Format the user-facing XML error message.
+fn format_xml_error(error: roxmltree::Error) -> String {
+    format_xml_like_error("xml file", error)
+}