1 files changed, 123 insertions, 0 deletions
diff --git a/src/model/items.rs b/src/model/items.rs
new file mode 100644
index 00000000..164d9602
--- /dev/null
+++ b/src/model/items.rs
@@ -0,0 +1,123 @@
+use std::fmt::{self, Debug, Formatter};
+use std::hash::{Hash, Hasher};
+use std::num::NonZeroUsize;
+
+use comemo::Tracked;
+use once_cell::sync::OnceCell;
+
+use super::{Content, StyleChain};
+use crate::diag::SourceResult;
+use crate::frame::Frame;
+use crate::geom::{Abs, Dir};
+use crate::util::{hash128, EcoString};
+use crate::World;
+
+/// Global storage for lang items.
+#[doc(hidden)]
+pub static LANG_ITEMS: OnceCell<LangItems> = OnceCell::new();
+
+/// Set the lang items. This is a hack :(
+///
+/// Passing the lang items everywhere they are needed (especially the text node
+/// related things) is very painful. By storing them globally, in theory, we
+/// break incremental, but only when different sets of lang items are used in
+/// the same program. For this reason, if this function is called multiple
+/// times, the items must be the same.
+pub fn set_lang_items(items: LangItems) {
+    if LANG_ITEMS.set(items).is_err() {
+        let first = hash128(LANG_ITEMS.get().unwrap());
+        let second = hash128(&items);
+        assert_eq!(first, second, "set differing lang items");
+    }
+}
+
+/// Access a lang item.
+macro_rules! item {
+    ($name:ident) => {
+        $crate::model::LANG_ITEMS.get().unwrap().$name
+    };
+}
+
+/// Definition of certain standard library items the language is aware of.
+#[derive(Copy, Clone)]
+pub struct LangItems {
+    /// The root layout function.
+    pub root:
+        fn(world: Tracked<dyn World>, document: &Content) -> SourceResult<Vec<Frame>>,
+    /// Access the em size.
+    pub em: fn(StyleChain) -> Abs,
+    /// Access the text direction.
+    pub dir: fn(StyleChain) -> Dir,
+    /// A space.
+    pub space: fn() -> Content,
+    /// A forced line break.
+    pub linebreak: fn(justify: bool) -> Content,
+    /// Plain text.
+    pub text: fn(text: EcoString) -> Content,
+    /// A smart quote: `'` or `"`.
+    pub smart_quote: fn(double: bool) -> Content,
+    /// A paragraph break.
+    pub parbreak: fn() -> Content,
+    /// Strong content: `*Strong*`.
+    pub strong: fn(body: Content) -> Content,
+    /// Emphasized content: `_Emphasized_`.
+    pub emph: fn(body: Content) -> Content,
+    /// A raw block with optional syntax highlighting: `` `...` ``.
+    pub raw: fn(text: EcoString, tag: Option<EcoString>, block: bool) -> Content,
+    /// A hyperlink: `https://typst.org`.
+    pub link: fn(url: EcoString) -> Content,
+    /// A reference: `@target`.
+    pub ref_: fn(target: EcoString) -> Content,
+    /// A section heading: `= Introduction`.
+    pub heading: fn(level: NonZeroUsize, body: Content) -> Content,
+    /// An item in an unordered list: `- ...`.
+    pub list_item: fn(body: Content) -> Content,
+    /// An item in an enumeration (ordered list): `1. ...`.
+    pub enum_item: fn(number: Option<usize>, body: Content) -> Content,
+    /// An item in a description list: `/ Term: Details`.
+    pub desc_item: fn(term: Content, body: Content) -> Content,
+    /// A math formula: `$x$`, `$ x^2 $`.
+    pub math: fn(children: Vec<Content>, display: bool) -> Content,
+    /// A atom in a formula: `x`, `+`, `12`.
+    pub math_atom: fn(atom: EcoString) -> Content,
+    /// A base with an optional sub- and superscript in a formula: `a_1^2`.
+    pub math_script:
+        fn(base: Content, sub: Option<Content>, sup: Option<Content>) -> Content,
+    /// A fraction in a formula: `x/2`
+    pub math_frac: fn(num: Content, denom: Content) -> Content,
+    /// An alignment indicator in a formula: `&`, `&&`.
+    pub math_align: fn(count: usize) -> Content,
+}
+
+impl Debug for LangItems {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        f.pad("LangItems { .. }")
+    }
+}
+
+impl Hash for LangItems {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        (self.root as usize).hash(state);
+        (self.em as usize).hash(state);
+        (self.dir as usize).hash(state);
+        self.space.hash(state);
+        self.linebreak.hash(state);
+        self.text.hash(state);
+        self.smart_quote.hash(state);
+        self.parbreak.hash(state);
+        self.strong.hash(state);
+        self.emph.hash(state);
+        self.raw.hash(state);
+        self.link.hash(state);
+        self.ref_.hash(state);
+        self.heading.hash(state);
+        self.list_item.hash(state);
+        self.enum_item.hash(state);
+        self.desc_item.hash(state);
+        self.math.hash(state);
+        self.math_atom.hash(state);
+        self.math_script.hash(state);
+        self.math_frac.hash(state);
+        self.math_align.hash(state);
+    }
+}