Start & end alignment

4 files changed, 56 insertions, 5 deletions

diff --git a/src/eval/layout.rs b/src/eval/layout.rs
index 9bf44194..09b69253 100644
--- a/src/eval/layout.rs
+++ b/src/eval/layout.rs
@@ -5,7 +5,7 @@ use std::fmt::{self, Debug, Formatter};
 use std::hash::Hash;
 use std::sync::Arc;
 
-use super::{Barrier, StyleChain};
+use super::{Barrier, RawAlign, StyleChain};
 use crate::diag::TypResult;
 use crate::frame::{Element, Frame, Geometry, Shape, Stroke};
 use crate::geom::{
@@ -182,7 +182,7 @@ impl LayoutNode {
     }
 
     /// Set alignments for this node.
-    pub fn aligned(self, aligns: Spec<Option<Align>>) -> Self {
+    pub fn aligned(self, aligns: Spec<Option<RawAlign>>) -> Self {
         if aligns.any(Option::is_some) {
             AlignNode { aligns, child: self }.pack()
         } else {
diff --git a/src/eval/mod.rs b/src/eval/mod.rs
index e83c8159..8b777a64 100644
--- a/src/eval/mod.rs
+++ b/src/eval/mod.rs
@@ -17,6 +17,7 @@ mod func;
 mod layout;
 mod module;
 mod ops;
+mod raw;
 mod scope;
 mod show;
 mod str;
@@ -32,6 +33,7 @@ pub use dict::*;
 pub use func::*;
 pub use layout::*;
 pub use module::*;
+pub use raw::*;
 pub use scope::*;
 pub use show::*;
 pub use styles::*;
diff --git a/src/eval/ops.rs b/src/eval/ops.rs
index ff21d93f..0ba4320e 100644
--- a/src/eval/ops.rs
+++ b/src/eval/ops.rs
@@ -1,8 +1,8 @@
 use std::cmp::Ordering;
 
-use super::{Dynamic, StrExt, Value};
+use super::{Dynamic, RawAlign, StrExt, Value};
 use crate::diag::StrResult;
-use crate::geom::{Align, Numeric, Spec, SpecAxis};
+use crate::geom::{Numeric, Spec, SpecAxis};
 use Value::*;
 
 /// Bail with a type mismatch error.
@@ -94,7 +94,7 @@ pub fn add(lhs: Value, rhs: Value) -> StrResult<Value> {
             if let (Dyn(a), Dyn(b)) = (&a, &b) {
                 // 1D alignments can be summed into 2D alignments.
                 if let (Some(&a), Some(&b)) =
-                    (a.downcast::<Align>(), b.downcast::<Align>())
+                    (a.downcast::<RawAlign>(), b.downcast::<RawAlign>())
                 {
                     return if a.axis() != b.axis() {
                         Ok(Dyn(Dynamic::new(match a.axis() {
diff --git a/src/eval/raw.rs b/src/eval/raw.rs
new file mode 100644
index 00000000..337638f9
--- /dev/null
+++ b/src/eval/raw.rs
@@ -0,0 +1,49 @@
+use std::fmt::{self, Debug, Formatter};
+
+use super::{Resolve, StyleChain};
+use crate::geom::{Align, SpecAxis};
+use crate::library::text::ParNode;
+
+/// The unresolved alignment representation.
+#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+pub enum RawAlign {
+    /// Align at the start side of the text direction.
+    Start,
+    /// Align at the end side of the text direction.
+    End,
+    /// Align at a specific alignment.
+    Specific(Align),
+}
+
+impl Resolve for RawAlign {
+    type Output = Align;
+
+    fn resolve(self, styles: StyleChain) -> Self::Output {
+        let dir = styles.get(ParNode::DIR);
+        match self {
+            Self::Start => dir.start().into(),
+            Self::End => dir.end().into(),
+            Self::Specific(align) => align,
+        }
+    }
+}
+
+impl RawAlign {
+    /// The axis this alignment belongs to.
+    pub const fn axis(self) -> SpecAxis {
+        match self {
+            Self::Start | Self::End => SpecAxis::Horizontal,
+            Self::Specific(align) => align.axis(),
+        }
+    }
+}
+
+impl Debug for RawAlign {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        match self {
+            Self::Start => f.pad("left"),
+            Self::End => f.pad("center"),
+            Self::Specific(align) => align.fmt(f),
+        }
+    }
+}