Split out four new crates (#5302)

1 files changed, 132 insertions, 0 deletions

diff --git a/crates/typst-library/src/layout/dir.rs b/crates/typst-library/src/layout/dir.rs
new file mode 100644
index 00000000..9a2e7710
--- /dev/null
+++ b/crates/typst-library/src/layout/dir.rs
@@ -0,0 +1,132 @@
+use ecow::EcoString;
+
+use crate::foundations::{func, scope, ty, Repr};
+use crate::layout::{Axis, Side};
+
+/// The four directions into which content can be laid out.
+///
+///  Possible values are:
+/// - `{ltr}`: Left to right.
+/// - `{rtl}`: Right to left.
+/// - `{ttb}`: Top to bottom.
+/// - `{btt}`: Bottom to top.
+///
+/// These values are available globally and
+/// also in the direction type's scope, so you can write either of the following
+/// two:
+/// ```example
+/// #stack(dir: rtl)[A][B][C]
+/// #stack(dir: direction.rtl)[A][B][C]
+/// ```
+#[ty(scope, name = "direction")]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
+pub enum Dir {
+    /// Left to right.
+    LTR,
+    /// Right to left.
+    RTL,
+    /// Top to bottom.
+    TTB,
+    /// Bottom to top.
+    BTT,
+}
+
+impl Dir {
+    /// Whether this direction points into the positive coordinate direction.
+    ///
+    /// The positive directions are left-to-right and top-to-bottom.
+    pub const fn is_positive(self) -> bool {
+        match self {
+            Self::LTR | Self::TTB => true,
+            Self::RTL | Self::BTT => false,
+        }
+    }
+}
+
+#[scope]
+impl Dir {
+    pub const LTR: Self = Self::LTR;
+    pub const RTL: Self = Self::RTL;
+    pub const TTB: Self = Self::TTB;
+    pub const BTT: Self = Self::BTT;
+
+    /// The axis this direction belongs to, either `{"horizontal"}` or
+    /// `{"vertical"}`.
+    ///
+    /// ```example
+    /// #ltr.axis() \
+    /// #ttb.axis()
+    /// ```
+    #[func]
+    pub const fn axis(self) -> Axis {
+        match self {
+            Self::LTR | Self::RTL => Axis::X,
+            Self::TTB | Self::BTT => Axis::Y,
+        }
+    }
+
+    /// The start point of this direction, as an alignment.
+    ///
+    /// ```example
+    /// #ltr.start() \
+    /// #rtl.start() \
+    /// #ttb.start() \
+    /// #btt.start()
+    /// ```
+    #[func]
+    pub const fn start(self) -> Side {
+        match self {
+            Self::LTR => Side::Left,
+            Self::RTL => Side::Right,
+            Self::TTB => Side::Top,
+            Self::BTT => Side::Bottom,
+        }
+    }
+
+    /// The end point of this direction, as an alignment.
+    ///
+    /// ```example
+    /// #ltr.end() \
+    /// #rtl.end() \
+    /// #ttb.end() \
+    /// #btt.end()
+    /// ```
+    #[func]
+    pub const fn end(self) -> Side {
+        match self {
+            Self::LTR => Side::Right,
+            Self::RTL => Side::Left,
+            Self::TTB => Side::Bottom,
+            Self::BTT => Side::Top,
+        }
+    }
+
+    /// The inverse direction.
+    ///
+    /// ```example
+    /// #ltr.inv() \
+    /// #rtl.inv() \
+    /// #ttb.inv() \
+    /// #btt.inv()
+    /// ```
+    #[func(title = "Inverse")]
+    pub const fn inv(self) -> Dir {
+        match self {
+            Self::LTR => Self::RTL,
+            Self::RTL => Self::LTR,
+            Self::TTB => Self::BTT,
+            Self::BTT => Self::TTB,
+        }
+    }
+}
+
+impl Repr for Dir {
+    fn repr(&self) -> EcoString {
+        match self {
+            Self::LTR => "ltr".into(),
+            Self::RTL => "rtl".into(),
+            Self::TTB => "ttb".into(),
+            Self::BTT => "btt".into(),
+        }
+    }
+}