1 files changed, 103 insertions, 0 deletions
diff --git a/crates/typst-library/src/math/op.rs b/crates/typst-library/src/math/op.rs
new file mode 100644
index 00000000..ef24705a
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+++ b/crates/typst-library/src/math/op.rs
@@ -0,0 +1,103 @@
+use ecow::EcoString;
+
+use crate::foundations::{elem, Content, NativeElement, Scope};
+use crate::layout::HElem;
+use crate::math::{upright, Mathy, THIN};
+use crate::text::TextElem;
+
+/// A text operator in an equation.
+///
+/// # Example
+/// ```example
+/// $ tan x = (sin x)/(cos x) $
+/// $ op("custom",
+///      limits: #true)_(n->oo) n $
+/// ```
+///
+/// # Predefined Operators { #predefined }
+/// Typst predefines the operators `arccos`, `arcsin`, `arctan`, `arg`, `cos`,
+/// `cosh`, `cot`, `coth`, `csc`, `csch`, `ctg`, `deg`, `det`, `dim`, `exp`,
+/// `gcd`, `hom`, `id`, `im`, `inf`, `ker`, `lg`, `lim`, `liminf`, `limsup`,
+/// `ln`, `log`, `max`, `min`, `mod`, `Pr`, `sec`, `sech`, `sin`, `sinc`,
+/// `sinh`, `sup`, `tan`, `tanh`, `tg` and `tr`.
+#[elem(title = "Text Operator", Mathy)]
+pub struct OpElem {
+    /// The operator's text.
+    #[required]
+    pub text: Content,
+
+    /// Whether the operator should show attachments as limits in display mode.
+    #[default(false)]
+    pub limits: bool,
+}
+
+macro_rules! ops {
+    ($($name:ident $(: $value:literal)? $(($tts:tt))?),* $(,)?) => {
+        pub(super) fn define(math: &mut Scope) {
+            $({
+                let operator = EcoString::from(ops!(@name $name $(: $value)?));
+                math.define(
+                    stringify!($name),
+                    OpElem::new(TextElem::new(operator).into())
+                        .with_limits(ops!(@limit $($tts)*))
+                        .pack()
+                );
+            })*
+
+            let dif = |d| {
+                HElem::new(THIN.into()).with_weak(true).pack()
+                    + upright(TextElem::packed(d))
+            };
+            math.define("dif", dif('d'));
+            math.define("Dif", dif('D'));
+        }
+    };
+    (@name $name:ident) => { stringify!($name) };
+    (@name $name:ident: $value:literal) => { $value };
+    (@limit limits) => { true };
+    (@limit) => { false };
+}
+
+ops! {
+    arccos,
+    arcsin,
+    arctan,
+    arg,
+    cos,
+    cosh,
+    cot,
+    coth,
+    csc,
+    csch,
+    ctg,
+    deg,
+    det (limits),
+    dim,
+    exp,
+    gcd (limits),
+    hom,
+    id,
+    im,
+    inf (limits),
+    ker,
+    lg,
+    lim (limits),
+    liminf: "lim inf" (limits),
+    limsup: "lim sup" (limits),
+    ln,
+    log,
+    max (limits),
+    min (limits),
+    mod,
+    Pr (limits),
+    sec,
+    sech,
+    sin,
+    sinc,
+    sinh,
+    sup (limits),
+    tan,
+    tanh,
+    tg,
+    tr,
+}