1 files changed, 137 insertions, 0 deletions
diff --git a/crates/typst-library/src/meta/link.rs b/crates/typst-library/src/meta/link.rs
new file mode 100644
index 00000000..2a53b84f
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+++ b/crates/typst-library/src/meta/link.rs
@@ -0,0 +1,137 @@
+use crate::prelude::*;
+use crate::text::{Hyphenate, TextElem};
+
+/// Links to a URL or a location in the document.
+///
+/// By default, links are not styled any different from normal text. However,
+/// you can easily apply a style of your choice with a show rule.
+///
+/// ## Example { #example }
+/// ```example
+/// #show link: underline
+///
+/// https://example.com \
+///
+/// #link("https://example.com") \
+/// #link("https://example.com")[
+///   See example.com
+/// ]
+/// ```
+///
+/// ## Syntax { #syntax }
+/// This function also has dedicated syntax: Text that starts with `http://` or
+/// `https://` is automatically turned into a link.
+///
+/// Display: Link
+/// Category: meta
+#[element(Show)]
+pub struct LinkElem {
+    /// The destination the link points to.
+    ///
+    /// - To link to web pages, `dest` should be a valid URL string. If the URL
+    ///   is in the `mailto:` or `tel:` scheme and the `body` parameter is
+    ///   omitted, the email address or phone number will be the link's body,
+    ///   without the scheme.
+    ///
+    /// - To link to another part of the document, `dest` can take one of three
+    ///   forms:
+    ///   - A [label]($func/label) attached to an element. If you also want
+    ///     automatic text for the link based on the element, consider using
+    ///     a [reference]($func/ref) instead.
+    ///
+    ///   - A [location]($func/locate) resulting from a [`locate`]($func/locate)
+    ///     call or [`query`]($func/query).
+    ///
+    ///   - A dictionary with a `page` key of type [integer]($type/integer) and
+    ///     `x` and `y` coordinates of type [length]($type/length). Pages are
+    ///     counted from one, and the coordinates are relative to the page's top
+    ///     left corner.
+    ///
+    /// ```example
+    /// = Introduction <intro>
+    /// #link("mailto:hello@typst.app") \
+    /// #link(<intro>)[Go to intro] \
+    /// #link((page: 1, x: 0pt, y: 0pt))[
+    ///   Go to top
+    /// ]
+    /// ```
+    #[required]
+    #[parse(
+        let dest = args.expect::<LinkTarget>("destination")?;
+        dest.clone()
+    )]
+    pub dest: LinkTarget,
+
+    /// The content that should become a link.
+    ///
+    /// If `dest` is an URL string, the parameter can be omitted. In this case,
+    /// the URL will be shown as the link.
+    #[required]
+    #[parse(match &dest {
+        LinkTarget::Dest(Destination::Url(url)) => match args.eat()? {
+            Some(body) => body,
+            None => body_from_url(url),
+        },
+        _ => args.expect("body")?,
+    })]
+    pub body: Content,
+}
+
+impl LinkElem {
+    /// Create a link element from a URL with its bare text.
+    pub fn from_url(url: EcoString) -> Self {
+        let body = body_from_url(&url);
+        Self::new(LinkTarget::Dest(Destination::Url(url)), body)
+    }
+}
+
+impl Show for LinkElem {
+    #[tracing::instrument(name = "LinkElem::show", skip(self, vt))]
+    fn show(&self, vt: &mut Vt, _: StyleChain) -> SourceResult<Content> {
+        let body = self.body();
+        let linked = match self.dest() {
+            LinkTarget::Dest(dest) => body.linked(dest),
+            LinkTarget::Label(label) => vt
+                .delayed(|vt| {
+                    let elem = vt.introspector.query_label(&label).at(self.span())?;
+                    let dest = Destination::Location(elem.location().unwrap());
+                    Ok(Some(body.clone().linked(dest)))
+                })
+                .unwrap_or(body),
+        };
+
+        Ok(linked.styled(TextElem::set_hyphenate(Hyphenate(Smart::Custom(false)))))
+    }
+}
+
+fn body_from_url(url: &EcoString) -> Content {
+    let mut text = url.as_str();
+    for prefix in ["mailto:", "tel:"] {
+        text = text.trim_start_matches(prefix);
+    }
+    let shorter = text.len() < url.len();
+    TextElem::packed(if shorter { text.into() } else { url.clone() })
+}
+
+/// A target where a link can go.
+#[derive(Debug, Clone)]
+pub enum LinkTarget {
+    Dest(Destination),
+    Label(Label),
+}
+
+cast! {
+    LinkTarget,
+    self => match self {
+        Self::Dest(v) => v.into_value(),
+        Self::Label(v) => v.into_value(),
+    },
+    v: Destination => Self::Dest(v),
+    v: Label => Self::Label(v),
+}
+
+impl From<Destination> for LinkTarget {
+    fn from(dest: Destination) -> Self {
+        Self::Dest(dest)
+    }
+}