Initial work on XML support.

Cargo.toml

@@ -3,6 +3,7 @@ members = [
     "jaq-core",
     "jaq-std",
     "jaq-json",
+    "jaq-xml",
     "jaq",
     "jaq-play",
 ]

jaq-xml/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "jaq-xml"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+quick-xml = {version = "0.37.2", features = []}

jaq-xml/src/main.rs

@@ -0,0 +1,63 @@
+use quick_xml::errors::{Error, Result};
+use quick_xml::events::attributes::Attribute;
+use quick_xml::events::{BytesStart, BytesText, Event};
+use quick_xml::reader::Reader;
+
+#[derive(Debug)]
+enum Node {
+    Tac(String, Vec<(String, String)>, Vec<Node>),
+    Text(String),
+    Comment(String),
+    Doctype(String),
+    Pi(String),
+}
+
+fn parse_many(read: &mut Reader<&[u8]>, root: bool) -> Result<Vec<Node>> {
+    core::iter::from_fn(|| parse2(read, root).transpose()).collect()
+}
+
+fn parse2(read: &mut Reader<&[u8]>, root: bool) -> Result<Option<Node>> {
+    let u8_str = |u: &[u8]| {
+        std::str::from_utf8(u)
+            .map_err(|e| Error::Encoding(e.into()))
+            .map(|s| s.to_owned())
+    };
+    let text_str = |t: BytesText| t.unescape().map(|s| s.into_owned());
+    let attr =
+        |a: Attribute| Ok::<_, Error>((u8_str(a.key.as_ref())?, a.unescape_value()?.into_owned()));
+    let attrs = |s: BytesStart| s.attributes().map(|a| Ok(attr(a?)?)).collect::<Result<_>>();
+
+    Ok(Some(match read.read_event()? {
+        Event::End(_) => return Ok(None),
+        Event::Eof if root => return Ok(None),
+        Event::Eof => panic!(),
+        Event::Start(start) => {
+            let tag = u8_str(start.name().as_ref())?;
+            Node::Tac(tag, attrs(start)?, parse_many(read, false)?)
+        }
+        Event::Empty(start) => {
+            let tag = u8_str(start.name().as_ref())?;
+            Node::Tac(tag, attrs(start)?, Vec::new())
+        }
+        Event::Text(e) => Node::Text(text_str(e)?),
+        Event::Comment(e) => Node::Comment(text_str(e)?),
+        Event::PI(pi) => Node::Pi(u8_str(&pi)?),
+        Event::CData(cd) => Node::Text(u8_str(&cd.into_inner())?),
+        Event::DocType(dt) => Node::Doctype(text_str(dt)?),
+        Event::Decl(d) => Node::Pi(u8_str(&d)?),
+    }))
+}
+
+fn main() {
+    let xml = r#"<?xml version = '1.0' ?><tag1 att1 = "test">
+                <bla/>
+                <?bla blu?>
+                <tag2><!--Test comment-->Test</tag2>
+                <tag2>Test 2</tag2>
+             </tag1>"#;
+    let mut read = Reader::from_str(xml);
+    read.config_mut().trim_text(true);
+
+    let nodes = parse_many(&mut read, true);
+    dbg!(nodes);
+}