1 files changed, 84 insertions, 0 deletions
diff --git a/crates/typst-library/src/layout/stack.rs b/crates/typst-library/src/layout/stack.rs
new file mode 100644
index 00000000..5fc78480
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+++ b/crates/typst-library/src/layout/stack.rs
@@ -0,0 +1,84 @@
+use std::fmt::{self, Debug, Formatter};
+
+use crate::diag::SourceResult;
+use crate::engine::Engine;
+use crate::foundations::{cast, elem, Content, NativeElement, Packed, Show, StyleChain};
+use crate::layout::{BlockElem, Dir, Spacing};
+
+/// Arranges content and spacing horizontally or vertically.
+///
+/// The stack places a list of items along an axis, with optional spacing
+/// between each item.
+///
+/// # Example
+/// ```example
+/// #stack(
+///   dir: ttb,
+///   rect(width: 40pt),
+///   rect(width: 120pt),
+///   rect(width: 90pt),
+/// )
+/// ```
+#[elem(Show)]
+pub struct StackElem {
+    /// The direction along which the items are stacked. Possible values are:
+    ///
+    /// - `{ltr}`: Left to right.
+    /// - `{rtl}`: Right to left.
+    /// - `{ttb}`: Top to bottom.
+    /// - `{btt}`: Bottom to top.
+    ///
+    /// You can use the `start` and `end` methods to obtain the initial and
+    /// final points (respectively) of a direction, as `alignment`. You can also
+    /// use the `axis` method to determine whether a direction is
+    /// `{"horizontal"}` or `{"vertical"}`. The `inv` method returns a
+    /// direction's inverse direction.
+    ///
+    /// For example, `{ttb.start()}` is `top`, `{ttb.end()}` is `bottom`,
+    /// `{ttb.axis()}` is `{"vertical"}` and `{ttb.inv()}` is equal to `btt`.
+    #[default(Dir::TTB)]
+    pub dir: Dir,
+
+    /// Spacing to insert between items where no explicit spacing was provided.
+    pub spacing: Option<Spacing>,
+
+    /// The children to stack along the axis.
+    #[variadic]
+    pub children: Vec<StackChild>,
+}
+
+impl Show for Packed<StackElem> {
+    fn show(&self, engine: &mut Engine, _: StyleChain) -> SourceResult<Content> {
+        Ok(BlockElem::multi_layouter(self.clone(), engine.routines.layout_stack)
+            .pack()
+            .spanned(self.span()))
+    }
+}
+
+/// A child of a stack element.
+#[derive(Clone, PartialEq, Hash)]
+pub enum StackChild {
+    /// Spacing between other children.
+    Spacing(Spacing),
+    /// Arbitrary block-level content.
+    Block(Content),
+}
+
+impl Debug for StackChild {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        match self {
+            Self::Spacing(kind) => kind.fmt(f),
+            Self::Block(block) => block.fmt(f),
+        }
+    }
+}
+
+cast! {
+    StackChild,
+    self => match self {
+        Self::Spacing(spacing) => spacing.into_value(),
+        Self::Block(content) => content.into_value(),
+    },
+    v: Spacing => Self::Spacing(v),
+    v: Content => Self::Block(v),
+}