Fixed-point decimal type (#4900)

Co-authored-by: Laurenz <laurmaedje@gmail.com>

22 files changed, 1087 insertions, 148 deletions

diff --git a/Cargo.lock b/Cargo.lock
index b516363c..df886fbd 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2028,6 +2028,16 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6c20b6793b5c2fa6553b250154b78d6d0db37e72700ae35fad9387a46f487c97"
 
 [[package]]
+name = "rust_decimal"
+version = "1.36.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b082d80e3e3cc52b2ed634388d436fe1f4de6af5786cc2de9ba9737527bdf555"
+dependencies = [
+ "arrayvec",
+ "num-traits",
+]
+
+[[package]]
 name = "rustc-hash"
 version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -2666,6 +2676,7 @@ dependencies = [
  "rayon",
  "regex",
  "roxmltree",
+ "rust_decimal",
  "rustybuzz",
  "serde",
  "serde_json",
diff --git a/Cargo.toml b/Cargo.toml
index e3cfc702..980d6f4c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -90,6 +90,7 @@ rayon = "1.7.0"
 regex = "1"
 resvg = { version = "0.43", default-features = false, features = ["raster-images"] }
 roxmltree = "0.20"
+rust_decimal = { version = "1.36.0", default-features = false, features = ["maths"] }
 rustybuzz = "0.18"
 same-file = "1"
 self-replace = "1.3.7"
diff --git a/crates/typst/Cargo.toml b/crates/typst/Cargo.toml
index 2b9c5d1a..a3e21123 100644
--- a/crates/typst/Cargo.toml
+++ b/crates/typst/Cargo.toml
@@ -52,6 +52,7 @@ portable-atomic = { workspace = true }
 rayon = { workspace = true }
 regex = { workspace = true }
 roxmltree = { workspace = true }
+rust_decimal = { workspace = true }
 rustybuzz = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
diff --git a/crates/typst/src/eval/ops.rs b/crates/typst/src/eval/ops.rs
index c9c8a24e..52032ae9 100644
--- a/crates/typst/src/eval/ops.rs
+++ b/crates/typst/src/eval/ops.rs
@@ -139,6 +139,7 @@ pub fn pos(value: Value) -> HintedStrResult<Value> {
     Ok(match value {
         Int(v) => Int(v),
         Float(v) => Float(v),
+        Decimal(v) => Decimal(v),
         Length(v) => Length(v),
         Angle(v) => Angle(v),
         Ratio(v) => Ratio(v),
@@ -164,6 +165,7 @@ pub fn neg(value: Value) -> HintedStrResult<Value> {
     Ok(match value {
         Int(v) => Int(v.checked_neg().ok_or_else(too_large)?),
         Float(v) => Float(-v),
+        Decimal(v) => Decimal(-v),
         Length(v) => Length(-v),
         Angle(v) => Angle(-v),
         Ratio(v) => Ratio(-v),
@@ -187,6 +189,17 @@ pub fn add(lhs: Value, rhs: Value) -> HintedStrResult<Value> {
         (Float(a), Int(b)) => Float(a + b as f64),
         (Float(a), Float(b)) => Float(a + b),
 
+        (Decimal(a), Decimal(b)) => Decimal(a.checked_add(b).ok_or_else(too_large)?),
+        (Decimal(a), Int(b)) => Decimal(
+            a.checked_add(crate::foundations::Decimal::from(b))
+                .ok_or_else(too_large)?,
+        ),
+        (Int(a), Decimal(b)) => Decimal(
+            crate::foundations::Decimal::from(a)
+                .checked_add(b)
+                .ok_or_else(too_large)?,
+        ),
+
         (Angle(a), Angle(b)) => Angle(a + b),
 
         (Length(a), Length(b)) => Length(a + b),
@@ -260,6 +273,17 @@ pub fn sub(lhs: Value, rhs: Value) -> HintedStrResult<Value> {
         (Float(a), Int(b)) => Float(a - b as f64),
         (Float(a), Float(b)) => Float(a - b),
 
+        (Decimal(a), Decimal(b)) => Decimal(a.checked_sub(b).ok_or_else(too_large)?),
+        (Decimal(a), Int(b)) => Decimal(
+            a.checked_sub(crate::foundations::Decimal::from(b))
+                .ok_or_else(too_large)?,
+        ),
+        (Int(a), Decimal(b)) => Decimal(
+            crate::foundations::Decimal::from(a)
+                .checked_sub(b)
+                .ok_or_else(too_large)?,
+        ),
+
         (Angle(a), Angle(b)) => Angle(a - b),
 
         (Length(a), Length(b)) => Length(a - b),
@@ -293,6 +317,17 @@ pub fn mul(lhs: Value, rhs: Value) -> HintedStrResult<Value> {
         (Float(a), Int(b)) => Float(a * b as f64),
         (Float(a), Float(b)) => Float(a * b),
 
+        (Decimal(a), Decimal(b)) => Decimal(a.checked_mul(b).ok_or_else(too_large)?),
+        (Decimal(a), Int(b)) => Decimal(
+            a.checked_mul(crate::foundations::Decimal::from(b))
+                .ok_or_else(too_large)?,
+        ),
+        (Int(a), Decimal(b)) => Decimal(
+            crate::foundations::Decimal::from(a)
+                .checked_mul(b)
+                .ok_or_else(too_large)?,
+        ),
+
         (Length(a), Int(b)) => Length(a * b as f64),
         (Length(a), Float(b)) => Length(a * b),
         (Length(a), Ratio(b)) => Length(a * b.get()),
@@ -356,6 +391,17 @@ pub fn div(lhs: Value, rhs: Value) -> HintedStrResult<Value> {
         (Float(a), Int(b)) => Float(a / b as f64),
         (Float(a), Float(b)) => Float(a / b),
 
+        (Decimal(a), Decimal(b)) => Decimal(a.checked_div(b).ok_or_else(too_large)?),
+        (Decimal(a), Int(b)) => Decimal(
+            a.checked_div(crate::foundations::Decimal::from(b))
+                .ok_or_else(too_large)?,
+        ),
+        (Int(a), Decimal(b)) => Decimal(
+            crate::foundations::Decimal::from(a)
+                .checked_div(b)
+                .ok_or_else(too_large)?,
+        ),
+
         (Length(a), Int(b)) => Length(a / b as f64),
         (Length(a), Float(b)) => Length(a / b),
         (Length(a), Length(b)) => Float(try_div_length(a, b)?),
@@ -394,6 +440,7 @@ fn is_zero(v: &Value) -> bool {
     match *v {
         Int(v) => v == 0,
         Float(v) => v == 0.0,
+        Decimal(v) => v.is_zero(),
         Length(v) => v.is_zero(),
         Angle(v) => v.is_zero(),
         Ratio(v) => v.is_zero(),
@@ -474,6 +521,7 @@ pub fn equal(lhs: &Value, rhs: &Value) -> bool {
         (Bool(a), Bool(b)) => a == b,
         (Int(a), Int(b)) => a == b,
         (Float(a), Float(b)) => a == b,
+        (Decimal(a), Decimal(b)) => a == b,
         (Length(a), Length(b)) => a == b,
         (Angle(a), Angle(b)) => a == b,
         (Ratio(a), Ratio(b)) => a == b,
@@ -499,6 +547,9 @@ pub fn equal(lhs: &Value, rhs: &Value) -> bool {
 
         // Some technically different things should compare equal.
         (&Int(i), &Float(f)) | (&Float(f), &Int(i)) => i as f64 == f,
+        (&Int(i), &Decimal(d)) | (&Decimal(d), &Int(i)) => {
+            crate::foundations::Decimal::from(i) == d
+        }
         (&Length(len), &Relative(rel)) | (&Relative(rel), &Length(len)) => {
             len == rel.abs && rel.rel.is_zero()
         }
@@ -520,6 +571,7 @@ pub fn compare(lhs: &Value, rhs: &Value) -> StrResult<Ordering> {
         (Bool(a), Bool(b)) => a.cmp(b),
         (Int(a), Int(b)) => a.cmp(b),
         (Float(a), Float(b)) => try_cmp_values(a, b)?,
+        (Decimal(a), Decimal(b)) => a.cmp(b),
         (Length(a), Length(b)) => try_cmp_values(a, b)?,
         (Angle(a), Angle(b)) => a.cmp(b),
         (Ratio(a), Ratio(b)) => a.cmp(b),
@@ -531,6 +583,8 @@ pub fn compare(lhs: &Value, rhs: &Value) -> StrResult<Ordering> {
         // Some technically different things should be comparable.
         (Int(a), Float(b)) => try_cmp_values(&(*a as f64), b)?,
         (Float(a), Int(b)) => try_cmp_values(a, &(*b as f64))?,
+        (Int(a), Decimal(b)) => crate::foundations::Decimal::from(*a).cmp(b),
+        (Decimal(a), Int(b)) => a.cmp(&crate::foundations::Decimal::from(*b)),
         (Length(a), Relative(b)) if b.rel.is_zero() => try_cmp_values(a, &b.abs)?,
         (Ratio(a), Relative(b)) if b.abs.is_zero() => a.cmp(&b.rel),
         (Relative(a), Length(b)) if a.rel.is_zero() => try_cmp_values(&a.abs, b)?,
diff --git a/crates/typst/src/foundations/calc.rs b/crates/typst/src/foundations/calc.rs
index 287bc828..f1faa73d 100644
--- a/crates/typst/src/foundations/calc.rs
+++ b/crates/typst/src/foundations/calc.rs
@@ -2,11 +2,12 @@
 
 use std::cmp;
 use std::cmp::Ordering;
-use std::ops::{Div, Rem};
 
-use crate::diag::{bail, At, SourceResult, StrResult};
+use az::SaturatingAs;
+
+use crate::diag::{bail, At, HintedString, SourceResult, StrResult};
 use crate::eval::ops;
-use crate::foundations::{cast, func, IntoValue, Module, Scope, Value};
+use crate::foundations::{cast, func, Decimal, IntoValue, Module, Scope, Value};
 use crate::layout::{Angle, Fr, Length, Ratio};
 use crate::syntax::{Span, Spanned};
 
@@ -61,7 +62,8 @@ pub fn module() -> Module {
 /// ```example
 /// #calc.abs(-5) \
 /// #calc.abs(5pt - 2cm) \
-/// #calc.abs(2fr)
+/// #calc.abs(2fr) \
+/// #calc.abs(decimal("-342.440"))
 /// ```
 #[func(title = "Absolute")]
 pub fn abs(
@@ -83,24 +85,28 @@ cast! {
     v: Angle => Self(Value::Angle(v.abs())),
     v: Ratio => Self(Value::Ratio(v.abs())),
     v: Fr => Self(Value::Fraction(v.abs())),
+    v: Decimal => Self(Value::Decimal(v.abs()))
 }
 
 /// Raises a value to some exponent.
 ///
 /// ```example
 /// #calc.pow(2, 3)
+/// #calc.pow(decimal("2.5"), 2)
 /// ```
 #[func(title = "Power")]
 pub fn pow(
     /// The callsite span.
     span: Span,
     /// The base of the power.
-    base: Num,
+    ///
+    /// If this is a [`decimal`], the exponent can only be an [integer]($int).
+    base: DecNum,
     /// The exponent of the power.
     exponent: Spanned<Num>,
-) -> SourceResult<Num> {
+) -> SourceResult<DecNum> {
     match exponent.v {
-        _ if exponent.v.float() == 0.0 && base.float() == 0.0 => {
+        _ if exponent.v.float() == 0.0 && base.is_zero() => {
             bail!(span, "zero to the power of zero is undefined")
         }
         Num::Int(i) if i32::try_from(i).is_err() => {
@@ -112,26 +118,37 @@ pub fn pow(
         _ => {}
     };
 
-    let result = match (base, exponent.v) {
-        (Num::Int(a), Num::Int(b)) if b >= 0 => {
-            a.checked_pow(b as u32).map(Num::Int).ok_or_else(too_large).at(span)?
+    match (base, exponent.v) {
+        (DecNum::Int(a), Num::Int(b)) if b >= 0 => a
+            .checked_pow(b as u32)
+            .map(DecNum::Int)
+            .ok_or_else(too_large)
+            .at(span),
+        (DecNum::Decimal(a), Num::Int(b)) => {
+            a.checked_powi(b).map(DecNum::Decimal).ok_or_else(too_large).at(span)
+        }
+        (a, b) => {
+            let Some(a) = a.float() else {
+                return Err(cant_apply_to_decimal_and_float()).at(span);
+            };
+
+            let result = if a == std::f64::consts::E {
+                b.float().exp()
+            } else if a == 2.0 {
+                b.float().exp2()
+            } else if let Num::Int(b) = b {
+                a.powi(b as i32)
+            } else {
+                a.powf(b.float())
+            };
+
+            if result.is_nan() {
+                bail!(span, "the result is not a real number")
+            }
+
+            Ok(DecNum::Float(result))
         }
-        (a, b) => Num::Float(if a.float() == std::f64::consts::E {
-            b.float().exp()
-        } else if a.float() == 2.0 {
-            b.float().exp2()
-        } else if let Num::Int(b) = b {
-            a.float().powi(b as i32)
-        } else {
-            a.float().powf(b.float())
-        }),
-    };
-
-    if result.float().is_nan() {
-        bail!(span, "the result is not a real number")
     }
-
-    Ok(result)
 }
 
 /// Raises a value to some exponent of e.
@@ -154,7 +171,7 @@ pub fn exp(
             bail!(exponent.span, "exponent may not be infinite, subnormal, or NaN")
         }
         _ => {}
-    };
+    }
 
     let result = exponent.v.float().exp();
     if result.is_nan() {
@@ -598,19 +615,28 @@ pub fn lcm(
 ///
 /// If the number is already an integer, it is returned unchanged.
 ///
+/// Note that this function will return the same type as the operand. That is,
+/// applying `floor` to a [`float`] will return a `float`, and to a [`decimal`],
+/// another `decimal`. You may explicitly convert the output of this function to
+/// an integer with [`int`], but note that such a conversion will error if the
+/// `float` or `decimal` is larger than the maximum 64-bit signed integer or
+/// smaller than the minimum integer.
+///
 /// ```example
-/// #assert(calc.floor(3.14) == 3)
 /// #assert(calc.floor(3) == 3)
+/// #assert(calc.floor(3.14) == 3.0)
+/// #assert(calc.floor(decimal("-3.14")) == decimal("-4"))
 /// #calc.floor(500.1)
 /// ```
 #[func]
 pub fn floor(
     /// The number to round down.
-    value: Num,
-) -> i64 {
+    value: DecNum,
+) -> DecNum {
     match value {
-        Num::Int(n) => n,
-        Num::Float(n) => n.floor() as i64,
+        DecNum::Int(n) => DecNum::Int(n),
+        DecNum::Float(n) => DecNum::Float(n.floor()),
+        DecNum::Decimal(n) => DecNum::Decimal(n.floor()),
     }
 }
 
@@ -618,19 +644,28 @@ pub fn floor(
 ///
 /// If the number is already an integer, it is returned unchanged.
 ///
+/// Note that this function will return the same type as the operand. That is,
+/// applying `ceil` to a [`float`] will return a `float`, and to a [`decimal`],
+/// another `decimal`. You may explicitly convert the output of this function to
+/// an integer with [`int`], but note that such a conversion will error if the
+/// `float` or `decimal` is larger than the maximum 64-bit signed integer or
+/// smaller than the minimum integer.
+///
 /// ```example
-/// #assert(calc.ceil(3.14) == 4)
 /// #assert(calc.ceil(3) == 3)
+/// #assert(calc.ceil(3.14) == 4)
+/// #assert(calc.ceil(decimal("-3.14")) == decimal("-3"))
 /// #calc.ceil(500.1)
 /// ```
 #[func]
 pub fn ceil(
     /// The number to round up.
-    value: Num,
-) -> i64 {
+    value: DecNum,
+) -> DecNum {
     match value {
-        Num::Int(n) => n,
-        Num::Float(n) => n.ceil() as i64,
+        DecNum::Int(n) => DecNum::Int(n),
+        DecNum::Float(n) => DecNum::Float(n.ceil()),
+        DecNum::Decimal(n) => DecNum::Decimal(n.ceil()),
     }
 }
 
@@ -638,19 +673,28 @@ pub fn ceil(
 ///
 /// If the number is already an integer, it is returned unchanged.
 ///
+/// Note that this function will return the same type as the operand. That is,
+/// applying `trunc` to a [`float`] will return a `float`, and to a [`decimal`],
+/// another `decimal`. You may explicitly convert the output of this function to
+/// an integer with [`int`], but note that such a conversion will error if the
+/// `float` or `decimal` is larger than the maximum 64-bit signed integer or
+/// smaller than the minimum integer.
+///
 /// ```example
 /// #assert(calc.trunc(3) == 3)
-/// #assert(calc.trunc(-3.7) == -3)
+/// #assert(calc.trunc(-3.7) == -3.0)
+/// #assert(calc.trunc(decimal("8493.12949582390")) == decimal("8493"))
 /// #calc.trunc(15.9)
 /// ```
 #[func(title = "Truncate")]
 pub fn trunc(
     /// The number to truncate.
-    value: Num,
-) -> i64 {
+    value: DecNum,
+) -> DecNum {
     match value {
-        Num::Int(n) => n,
-        Num::Float(n) => n.trunc() as i64,
+        DecNum::Int(n) => DecNum::Int(n),
+        DecNum::Float(n) => DecNum::Float(n.trunc()),
+        DecNum::Decimal(n) => DecNum::Decimal(n.trunc()),
     }
 }
 
@@ -660,16 +704,18 @@ pub fn trunc(
 ///
 /// ```example
 /// #assert(calc.fract(3) == 0)
+/// #assert(calc.fract(decimal("234.23949211")) == decimal("0.23949211"))
 /// #calc.fract(-3.1)
 /// ```
 #[func(title = "Fractional")]
 pub fn fract(
     /// The number to truncate.
-    value: Num,
-) -> Num {
+    value: DecNum,
+) -> DecNum {
     match value {
-        Num::Int(_) => Num::Int(0),
-        Num::Float(n) => Num::Float(n.fract()),
+        DecNum::Int(_) => DecNum::Int(0),
+        DecNum::Float(n) => DecNum::Float(n.fract()),
+        DecNum::Decimal(n) => DecNum::Decimal(n.fract()),
     }
 }
 
@@ -677,27 +723,37 @@ pub fn fract(
 ///
 /// Optionally, a number of decimal places can be specified.
 ///
+/// Note that this function will return the same type as the operand. That is,
+/// applying `round` to a [`float`] will return a `float`, and to a [`decimal`],
+/// another `decimal`. You may explicitly convert the output of this function to
+/// an integer with [`int`], but note that such a conversion will error if the
+/// `float` or `decimal` is larger than the maximum 64-bit signed integer or
+/// smaller than the minimum integer.
+///
 /// ```example
+/// #assert(calc.round(3) == 3)
 /// #assert(calc.round(3.14) == 3)
-/// #assert(calc.round(3.5) == 4)
+/// #assert(calc.round(3.5) == 4.0)
+/// #assert(calc.round(decimal("-6.5")) == decimal("-7"))
+/// #assert(calc.round(decimal("7.123456789"), digits: 6) == decimal("7.123457"))
 /// #calc.round(3.1415, digits: 2)
 /// ```
 #[func]
 pub fn round(
     /// The number to round.
-    value: Num,
-    /// The number of decimal places.
+    value: DecNum,
+    /// The number of decimal places. Must not be negative.
     #[named]
     #[default(0)]
-    digits: i64,
-) -> Num {
+    digits: u32,
+) -> DecNum {
     match value {
-        Num::Int(n) if digits == 0 => Num::Int(n),
-        _ => {
-            let n = value.float();
-            let factor = 10.0_f64.powi(digits as i32);
-            Num::Float((n * factor).round() / factor)
-        }
+        DecNum::Int(n) => DecNum::Int(n),
+        DecNum::Float(n) => DecNum::Float(crate::utils::format::round_with_precision(
+            n,
+            digits.saturating_as::<u8>(),
+        )),
+        DecNum::Decimal(n) => DecNum::Decimal(n.round(digits)),
     }
 }
 
@@ -706,21 +762,35 @@ pub fn round(
 /// ```example
 /// #assert(calc.clamp(5, 0, 10) == 5)
 /// #assert(calc.clamp(5, 6, 10) == 6)
+/// #assert(calc.clamp(decimal("5.45"), 2, decimal("45.9")) == decimal("5.45"))
+/// #assert(calc.clamp(decimal("5.45"), decimal("6.75"), 12) == decimal("6.75"))
 /// #calc.clamp(5, 0, 4)
 /// ```
 #[func]
 pub fn clamp(
+    /// The callsite span.
+    span: Span,
     /// The number to clamp.
-    value: Num,
+    value: DecNum,
     /// The inclusive minimum value.
-    min: Num,
+    min: DecNum,
     /// The inclusive maximum value.
-    max: Spanned<Num>,
-) -> SourceResult<Num> {
-    if max.v.float() < min.float() {
+    max: Spanned<DecNum>,
+) -> SourceResult<DecNum> {
+    // Ignore if there are incompatible types (decimal and float) since that
+    // will cause `apply3` below to error before calling clamp, avoiding a
+    // panic.
+    if min
+        .apply2(max.v, |min, max| max < min, |min, max| max < min, |min, max| max < min)
+        .unwrap_or(false)
+    {
         bail!(max.span, "max must be greater than or equal to min")
     }
-    Ok(value.apply3(min, max.v, i64::clamp, f64::clamp))
+
+    value
+        .apply3(min, max.v, i64::clamp, f64::clamp, Decimal::clamp)
+        .ok_or_else(cant_apply_to_decimal_and_float)
+        .at(span)
 }
 
 /// Determines the minimum of a sequence of values.
@@ -815,6 +885,9 @@ pub fn odd(
 /// The value `calc.rem(x, y)` always has the same sign as `x`, and is smaller
 /// in magnitude than `y`.
 ///
+/// This can error if given a [`decimal`] input and the dividend is too small in
+/// magnitude compared to the divisor.
+///
 /// ```example
 /// #calc.rem(7, 3) \
 /// #calc.rem(7, -3) \
@@ -824,15 +897,28 @@ pub fn odd(
 /// ```
 #[func(title = "Remainder")]
 pub fn rem(
+    /// The span of the function call.
+    span: Span,
     /// The dividend of the remainder.
-    dividend: Num,
+    dividend: DecNum,
     /// The divisor of the remainder.
-    divisor: Spanned<Num>,
-) -> SourceResult<Num> {
-    if divisor.v.float() == 0.0 {
+    divisor: Spanned<DecNum>,
+) -> SourceResult<DecNum> {
+    if divisor.v.is_zero() {
         bail!(divisor.span, "divisor must not be zero");
     }
-    Ok(dividend.apply2(divisor.v, Rem::rem, Rem::rem))
+
+    dividend
+        .apply2(
+            divisor.v,
+            |a, b| Some(DecNum::Int(a % b)),
+            |a, b| Some(DecNum::Float(a % b)),
+            |a, b| a.checked_rem(b).map(DecNum::Decimal),
+        )
+        .ok_or_else(cant_apply_to_decimal_and_float)
+        .at(span)?
+        .ok_or("dividend too small compared to divisor")
+        .at(span)
 }
 
 /// Performs euclidean division of two numbers.
@@ -845,45 +931,77 @@ pub fn rem(
 /// #calc.div-euclid(7, -3) \
 /// #calc.div-euclid(-7, 3) \
 /// #calc.div-euclid(-7, -3) \
-/// #calc.div-euclid(1.75, 0.5)
+/// #calc.div-euclid(1.75, 0.5) \
+/// #calc.div-euclid(decimal("1.75"), decimal("0.5"))
 /// ```
 #[func(title = "Euclidean Division")]
 pub fn div_euclid(
+    /// The callsite span.
+    span: Span,
     /// The dividend of the division.
-    dividend: Num,
+    dividend: DecNum,
     /// The divisor of the division.
-    divisor: Spanned<Num>,
-) -> SourceResult<Num> {
-    if divisor.v.float() == 0.0 {
+    divisor: Spanned<DecNum>,
+) -> SourceResult<DecNum> {
+    if divisor.v.is_zero() {
         bail!(divisor.span, "divisor must not be zero");
     }
-    Ok(dividend.apply2(divisor.v, i64::div_euclid, f64::div_euclid))
+
+    dividend
+        .apply2(
+            divisor.v,
+            |a, b| Some(DecNum::Int(a.div_euclid(b))),
+            |a, b| Some(DecNum::Float(a.div_euclid(b))),
+            |a, b| a.checked_div_euclid(b).map(DecNum::Decimal),
+        )
+        .ok_or_else(cant_apply_to_decimal_and_float)
+        .at(span)?
+        .ok_or_else(too_large)
+        .at(span)
 }
 
 /// This calculates the least nonnegative remainder of a division.
 ///
-/// Warning: Due to a floating point round-off error, the remainder may equal the absolute
-/// value of the divisor if the dividend is much smaller in magnitude than the divisor
-/// and the dividend is negative. This only applies for floating point inputs.
+/// Warning: Due to a floating point round-off error, the remainder may equal
+/// the absolute value of the divisor if the dividend is much smaller in
+/// magnitude than the divisor and the dividend is negative. This only applies
+/// for floating point inputs.
+///
+/// In addition, this can error if given a [`decimal`] input and the dividend is
+/// too small in magnitude compared to the divisor.
 ///
 /// ```example
 /// #calc.rem-euclid(7, 3) \
 /// #calc.rem-euclid(7, -3) \
 /// #calc.rem-euclid(-7, 3) \
 /// #calc.rem-euclid(-7, -3) \
-/// #calc.rem(1.75, 0.5)
+/// #calc.rem-euclid(1.75, 0.5)
+/// #calc.rem-euclid(decimal("1.75"), decimal("0.5"))
 /// ```
 #[func(title = "Euclidean Remainder")]
 pub fn rem_euclid(
+    /// The callsite span.
+    span: Span,
     /// The dividend of the remainder.
-    dividend: Num,
+    dividend: DecNum,
     /// The divisor of the remainder.
-    divisor: Spanned<Num>,
-) -> SourceResult<Num> {
-    if divisor.v.float() == 0.0 {
+    divisor: Spanned<DecNum>,
+) -> SourceResult<DecNum> {
+    if divisor.v.is_zero() {
         bail!(divisor.span, "divisor must not be zero");
     }
-    Ok(dividend.apply2(divisor.v, i64::rem_euclid, f64::rem_euclid))
+
+    dividend
+        .apply2(
+            divisor.v,
+            |a, b| Some(DecNum::Int(a.rem_euclid(b))),
+            |a, b| Some(DecNum::Float(a.rem_euclid(b))),
+            |a, b| a.checked_rem_euclid(b).map(DecNum::Decimal),
+        )
+        .ok_or_else(cant_apply_to_decimal_and_float)
+        .at(span)?
+        .ok_or("dividend too small compared to divisor")
+        .at(span)
 }
 
 /// Calculates the quotient (floored division) of two numbers.
@@ -895,16 +1013,30 @@ pub fn rem_euclid(
 /// ```
 #[func(title = "Quotient")]
 pub fn quo(
+    /// The span of the function call.
+    span: Span,
     /// The dividend of the quotient.
-    dividend: Num,
+    dividend: DecNum,
     /// The divisor of the quotient.
-    divisor: Spanned<Num>,
-) -> SourceResult<i64> {
-    if divisor.v.float() == 0.0 {
+    divisor: Spanned<DecNum>,
+) -> SourceResult<DecNum> {
+    if divisor.v.is_zero() {
         bail!(divisor.span, "divisor must not be zero");
     }
 
-    Ok(floor(dividend.apply2(divisor.v, Div::div, Div::div)))
+    let divided = dividend
+        .apply2(
+            divisor.v,
+            |a, b| Some(DecNum::Int(a / b)),
+            |a, b| Some(DecNum::Float(a / b)),
+            |a, b| a.checked_div(b).map(DecNum::Decimal),
+        )
+        .ok_or_else(cant_apply_to_decimal_and_float)
+        .at(span)?
+        .ok_or_else(too_large)
+        .at(span)?;
+
+    Ok(floor(divided))
 }
 
 /// A value which can be passed to functions that work with integers and floats.
@@ -915,47 +1047,119 @@ pub enum Num {
 }
 
 impl Num {
-    fn apply2(
+    fn float(self) -> f64 {
+        match self {
+            Self::Int(v) => v as f64,
+            Self::Float(v) => v,
+        }
+    }
+}
+
+cast! {
+    Num,
+    self => match self {
+        Self::Int(v) => v.into_value(),
+        Self::Float(v) => v.into_value(),
+    },
+    v: i64 => Self::Int(v),
+    v: f64 => Self::Float(v),
+}
+
+/// A value which can be passed to functions that work with integers, floats,
+/// and decimals.
+#[derive(Debug, Copy, Clone)]
+pub enum DecNum {
+    Int(i64),
+    Float(f64),
+    Decimal(Decimal),
+}
+
+impl DecNum {
+    /// Checks if this number is equivalent to zero.
+    fn is_zero(self) -> bool {
+        match self {
+            Self::Int(i) => i == 0,
+            Self::Float(f) => f == 0.0,
+            Self::Decimal(d) => d.is_zero(),
+        }
+    }
+
+    /// If this `DecNum` holds an integer or float, returns a float.
+    /// Otherwise, returns `None`.
+    fn float(self) -> Option<f64> {
+        match self {
+            Self::Int(i) => Some(i as f64),
+            Self::Float(f) => Some(f),
+            Self::Decimal(_) => None,
+        }
+    }
+
+    /// If this `DecNum` holds an integer or decimal, returns a decimal.
+    /// Otherwise, returns `None`.
+    fn decimal(self) -> Option<Decimal> {
+        match self {
+            Self::Int(i) => Some(Decimal::from(i)),
+            Self::Float(_) => None,
+            Self::Decimal(d) => Some(d),
+        }
+    }
+
+    /// Tries to apply a function to two decimal or numeric arguments.
+    ///
+    /// Fails with `None` if one is a float and the other is a decimal.
+    fn apply2<T>(
         self,
         other: Self,
-        int: impl FnOnce(i64, i64) -> i64,
-        float: impl FnOnce(f64, f64) -> f64,
-    ) -> Num {
+        int: impl FnOnce(i64, i64) -> T,
+        float: impl FnOnce(f64, f64) -> T,
+        decimal: impl FnOnce(Decimal, Decimal) -> T,
+    ) -> Option<T> {
         match (self, other) {
-            (Self::Int(a), Self::Int(b)) => Num::Int(int(a, b)),
-            (a, b) => Num::Float(float(a.float(), b.float())),
+            (Self::Int(a), Self::Int(b)) => Some(int(a, b)),
+            (Self::Decimal(a), Self::Decimal(b)) => Some(decimal(a, b)),
+            (Self::Decimal(a), Self::Int(b)) => Some(decimal(a, Decimal::from(b))),
+            (Self::Int(a), Self::Decimal(b)) => Some(decimal(Decimal::from(a), b)),
+            (a, b) => Some(float(a.float()?, b.float()?)),
         }
     }
 
+    /// Tries to apply a function to three decimal or numeric arguments.
+    ///
+    /// Fails with `None` if one is a float and the other is a decimal.
     fn apply3(
         self,
         other: Self,
         third: Self,
         int: impl FnOnce(i64, i64, i64) -> i64,
         float: impl FnOnce(f64, f64, f64) -> f64,
-    ) -> Num {
+        decimal: impl FnOnce(Decimal, Decimal, Decimal) -> Decimal,
+    ) -> Option<Self> {
         match (self, other, third) {
-            (Self::Int(a), Self::Int(b), Self::Int(c)) => Num::Int(int(a, b, c)),
-            (a, b, c) => Num::Float(float(a.float(), b.float(), c.float())),
-        }
-    }
-
-    fn float(self) -> f64 {
-        match self {
-            Self::Int(v) => v as f64,
-            Self::Float(v) => v,
+            (Self::Int(a), Self::Int(b), Self::Int(c)) => Some(Self::Int(int(a, b, c))),
+            (Self::Decimal(a), b, c) => {
+                Some(Self::Decimal(decimal(a, b.decimal()?, c.decimal()?)))
+            }
+            (a, Self::Decimal(b), c) => {
+                Some(Self::Decimal(decimal(a.decimal()?, b, c.decimal()?)))
+            }
+            (a, b, Self::Decimal(c)) => {
+                Some(Self::Decimal(decimal(a.decimal()?, b.decimal()?, c)))
+            }
+            (a, b, c) => Some(Self::Float(float(a.float()?, b.float()?, c.float()?))),
         }
     }
 }
 
 cast! {
-    Num,
+    DecNum,
     self => match self {
         Self::Int(v) => v.into_value(),
         Self::Float(v) => v.into_value(),
+        Self::Decimal(v) => v.into_value(),
     },
     v: i64 => Self::Int(v),
     v: f64 => Self::Float(v),
+    v: Decimal => Self::Decimal(v),
 }
 
 /// A value that can be passed to a trigonometric function.
@@ -977,3 +1181,14 @@ cast! {
 fn too_large() -> &'static str {
     "the result is too large"
 }
+
+/// The hinted error message when trying to apply an operation to decimal and
+/// float operands.
+#[cold]
+fn cant_apply_to_decimal_and_float() -> HintedString {
+    HintedString::new("cannot apply this operation to a decimal and a float".into())
+        .with_hint(
+            "if loss of precision is acceptable, explicitly cast the \
+             decimal to a float with `float(value)`",
+        )
+}
diff --git a/crates/typst/src/foundations/cast.rs b/crates/typst/src/foundations/cast.rs
index 51e36128..2dc69236 100644
--- a/crates/typst/src/foundations/cast.rs
+++ b/crates/typst/src/foundations/cast.rs
@@ -345,6 +345,13 @@ impl CastInfo {
                     msg.hint(eco_format!("use `label({})` to create a label", s.repr()));
                 }
             }
+        } else if let Value::Decimal(_) = found {
+            if !matching_type && parts.iter().any(|p| p == "float") {
+                msg.hint(eco_format!(
+                    "if loss of precision is acceptable, explicitly cast the \
+                     decimal to a float with `float(value)`"
+                ));
+            }
         }
 
         msg
diff --git a/crates/typst/src/foundations/decimal.rs b/crates/typst/src/foundations/decimal.rs
new file mode 100644
index 00000000..12d6499f
--- /dev/null
+++ b/crates/typst/src/foundations/decimal.rs
@@ -0,0 +1,369 @@
+use std::fmt::{self, Display, Formatter};
+use std::ops::Neg;
+use std::str::FromStr;
+
+use ecow::{eco_format, EcoString};
+use rust_decimal::MathematicalOps;
+
+use crate::diag::{warning, At, SourceResult};
+use crate::foundations::{cast, func, repr, scope, ty, Engine, Repr, Str};
+use crate::syntax::{ast, Span, Spanned};
+use crate::World;
+
+/// A fixed-point decimal number type.
+///
+/// This type should be used when highly precise arithmetic operations are
+/// needed, such as for finance. Typical operations between `{decimal}`
+/// numbers, such as addition, multiplication, and [power]($calc.pow) to an
+/// integer, will be highly precise due to their fixed-point representation.
+/// Note, however, that multiplication and division may not preserve all digits
+/// in some edge cases: while they are considered precise, digits past the
+/// limits specified below are rounded off and lost, so some loss of precision
+/// beyond the maximum representable digits is possible. Note that this
+/// behavior can be observed not only when dividing, but also when multiplying
+/// by numbers between 0 and 1, as both operations can push a number's
+/// fractional digits beyond the limits described below, leading to rounding.
+/// When those two operations do not surpass the digit limits, they are fully
+/// precise.
+///
+/// # Limits
+/// A `{decimal}` number has a limit of 28 to 29 significant base-10 digits.
+/// This includes the sum of digits before and after the decimal point. As
+/// such, numbers with more fractional digits have a smaller range. The maximum
+/// and minimum `{decimal}` numbers have a value of
+/// `{79228162514264337593543950335}` and `{-79228162514264337593543950335}`
+/// respectively. In contrast with [`{float}`]($float), this type does not
+/// support infinity or NaN, so overflowing or underflowing operations will
+/// raise an error.
+///
+/// # Construction and casts
+/// To create a decimal number, use the `{decimal(string)}` constructor, such
+/// as with `{decimal("3.141592653")}` **(note the double quotes!)**. This
+/// constructor preserves all given fractional digits, provided they are
+/// representable as per the limits above (otherwise, an error is raised). One
+/// may also convert any [integer]($int) to a decimal with the
+/// `{decimal(int)}` constructor, e.g. `{decimal(59)}`. However, note that
+/// constructing a decimal from a [floating-point number]($float), while
+/// supported, **is an imprecise conversion and therefore discouraged.** A
+/// warning will be raised if Typst detects that there was an accidental
+/// `{float}` to `{decimal}` cast through its constructor (e.g. if writing
+/// `{decimal(3.14)}` - note the lack of double quotes, indicating this is
+/// an accidental `{float}` cast and therefore imprecise). The precision of a
+/// `{float}` to `{decimal}` cast can be slightly improved by rounding the
+/// result to 15 digits with [`calc.round`]($calc.round), but there are still
+/// no precision guarantees for that kind of conversion.
+///
+/// In order to guard against accidental loss of precision, built-in operations
+/// between `{float}` and `{decimal}` are not supported and will raise an
+/// error. Certain `calc` functions, such as trigonometric functions and power
+/// between two real numbers, are also only supported for `{float}` (although
+/// raising `{decimal}` to integer exponents is supported). You can opt into
+/// potentially imprecise operations with the `{float(decimal)}` constructor,
+/// which casts the `{decimal}` number into a `{float}`, allowing for
+/// operations without precision guarantees.
+///
+/// # Example
+/// ```example
+/// #decimal("3.14159265358979323846264338") \
+/// #(decimal("0.000000000000000000001") + decimal("0.000000000000000000002"))
+/// #(decimal("0.00002") * decimal("49.25652565")) \
+/// #(decimal("1") / 2048)
+/// ```
+#[ty(scope, cast)]
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct Decimal(rust_decimal::Decimal);
+
+impl Decimal {
+    pub const ZERO: Self = Self(rust_decimal::Decimal::ZERO);
+    pub const ONE: Self = Self(rust_decimal::Decimal::ONE);
+
+    /// Whether this decimal value is zero.
+    pub const fn is_zero(self) -> bool {
+        self.0.is_zero()
+    }
+
+    /// Whether this decimal value is negative.
+    pub const fn is_negative(self) -> bool {
+        self.0.is_sign_negative()
+    }
+
+    /// Whether this decimal has fractional part equal to zero (is an integer).
+    pub fn is_integer(self) -> bool {
+        self.0.is_integer()
+    }
+
+    /// Computes the absolute value of this decimal.
+    pub fn abs(self) -> Self {
+        Self(self.0.abs())
+    }
+
+    /// Computes the largest integer less than or equal to this decimal.
+    ///
+    /// A decimal is returned as this may not be within `i64`'s range of
+    /// values.
+    pub fn floor(self) -> Self {
+        Self(self.0.floor())
+    }
+
+    /// Computes the smallest integer greater than or equal to this decimal.
+    ///
+    /// A decimal is returned as this may not be within `i64`'s range of
+    /// values.
+    pub fn ceil(self) -> Self {
+        Self(self.0.ceil())
+    }
+
+    /// Returns the integer part of this decimal.
+    pub fn trunc(self) -> Self {
+        Self(self.0.trunc())
+    }
+
+    /// Returns the fractional part of this decimal (with the integer part set
+    /// to zero).
+    pub fn fract(self) -> Self {
+        Self(self.0.fract())
+    }
+
+    /// Rounds this decimal up to the specified amount of digits with the
+    /// traditional rounding rules, using the "midpoint away from zero"
+    /// strategy (6.5 -> 7, -6.5 -> -7).
+    pub fn round(self, digits: u32) -> Self {
+        Self(self.0.round_dp_with_strategy(
+            digits,
+            rust_decimal::RoundingStrategy::MidpointAwayFromZero,
+        ))
+    }
+
+    /// Attempts to add two decimals.
+    ///
+    /// Returns `None` on overflow or underflow.
+    pub fn checked_add(self, other: Self) -> Option<Self> {
+        self.0.checked_add(other.0).map(Self)
+    }
+
+    /// Attempts to subtract a decimal from another.
+    ///
+    /// Returns `None` on overflow or underflow.
+    pub fn checked_sub(self, other: Self) -> Option<Self> {
+        self.0.checked_sub(other.0).map(Self)
+    }
+
+    /// Attempts to multiply two decimals.
+    ///
+    /// Returns `None` on overflow or underflow.
+    pub fn checked_mul(self, other: Self) -> Option<Self> {
+        self.0.checked_mul(other.0).map(Self)
+    }
+
+    /// Attempts to divide two decimals.
+    ///
+    /// Returns `None` if `other` is zero, as well as on overflow or underflow.
+    pub fn checked_div(self, other: Self) -> Option<Self> {
+        self.0.checked_div(other.0).map(Self)
+    }
+
+    /// Attempts to obtain the quotient of Euclidean division between two
+    /// decimals. Implemented similarly to [`f64::div_euclid`].
+    ///
+    /// The returned quotient is truncated and adjusted if the remainder was
+    /// negative.
+    ///
+    /// Returns `None` if `other` is zero, as well as on overflow or underflow.
+    pub fn checked_div_euclid(self, other: Self) -> Option<Self> {
+        let q = self.0.checked_div(other.0)?.trunc();
+        if self
+            .0
+            .checked_rem(other.0)
+            .as_ref()
+            .is_some_and(rust_decimal::Decimal::is_sign_negative)
+        {
+            return if other.0.is_sign_positive() {
+                q.checked_sub(rust_decimal::Decimal::ONE).map(Self)
+            } else {
+                q.checked_add(rust_decimal::Decimal::ONE).map(Self)
+            };
+        }
+        Some(Self(q))
+    }
+
+    /// Attempts to obtain the remainder of Euclidean division between two
+    /// decimals. Implemented similarly to [`f64::rem_euclid`].
+    ///
+    /// The returned decimal `r` is non-negative within the range
+    /// `0.0 <= r < other.abs()`.
+    ///
+    /// Returns `None` if `other` is zero, as well as on overflow or underflow.
+    pub fn checked_rem_euclid(self, other: Self) -> Option<Self> {
+        let r = self.0.checked_rem(other.0)?;
+        Some(Self(if r.is_sign_negative() { r.checked_add(other.0.abs())? } else { r }))
+    }
+
+    /// Attempts to calculate the remainder of the division of two decimals.
+    ///
+    /// Returns `None` if `other` is zero, as well as on overflow or underflow.
+    pub fn checked_rem(self, other: Self) -> Option<Self> {
+        self.0.checked_rem(other.0).map(Self)
+    }
+
+    /// Attempts to take one decimal to the power of an integer.
+    ///
+    /// Returns `None` for invalid operands, as well as on overflow or
+    /// underflow.
+    pub fn checked_powi(self, other: i64) -> Option<Self> {
+        self.0.checked_powi(other).map(Self)
+    }
+}
+
+#[scope]
+impl Decimal {
+    /// Converts a value to a `{decimal}`.
+    ///
+    /// It is recommended to use a string to construct the decimal number, or
+    /// an [integer]($int) (if desired). The string must contain a number in
+    /// the format `"3.14159"` (or `"-3.141519"` for negative numbers). The
+    /// fractional digits are fully preserved; if that's not possible due to
+    /// the limit of significant digits (around 28 to 29) having been reached,
+    /// an error is raised as the given decimal number wouldn't be
+    /// representable. For example, `{decimal("1.222222222222222")}` is a valid
+    /// decimal number.
+    ///
+    /// While this constructor can be used with
+    /// [floating-point numbers]($float) to cast them to `{decimal}`, doing so
+    /// is **discouraged** as **this cast is inherently imprecise.** It is easy
+    /// to accidentally perform this cast by writing `{decimal(1.234)}` (note
+    /// the lack of double quotes), which is why Typst will emit a warning in
+    /// that case. Please write `{decimal("1.234")}` instead for that
+    /// particular case (initialization of a constant decimal). Also note that
+    /// floats equal to NaN and infinity cannot be cast to decimals and will
+    /// raise an error.
+    #[func(constructor)]
+    pub fn construct(
+        engine: &mut Engine,
+        value: Spanned<ToDecimal>,
+    ) -> SourceResult<Decimal> {
+        match value.v {
+            ToDecimal::Str(str) => Self::from_str(&str.replace(repr::MINUS_SIGN, "-"))
+                .map_err(|_| eco_format!("invalid decimal: {str}"))
+                .at(value.span),
+            ToDecimal::Int(int) => Ok(Self::from(int)),
+            ToDecimal::Float(float) => {
+                warn_on_float_literal(engine, value.span);
+                Self::try_from(float)
+                    .map_err(|_| {
+                        eco_format!(
+                            "float is not a valid decimal: {}",
+                            repr::format_float(float, None, true, "")
+                        )
+                    })
+                    .at(value.span)
+            }
+        }
+    }
+}
+
+/// Emits a warning when a decimal is constructed from a float literal.
+fn warn_on_float_literal(engine: &mut Engine, span: Span) -> Option<()> {
+    let id = span.id()?;
+    let source = engine.world.source(id).ok()?;
+    let node = source.find(span)?;
+    if node.is::<ast::Float>() {
+        engine.sink.warn(warning!(
+            span,
+            "creating a decimal using imprecise float literal";
+            hint: "use a string in the decimal constructor to avoid loss \
+                   of precision: `decimal({})`",
+            node.text().repr()
+        ));
+    }
+    Some(())
+}
+
+impl FromStr for Decimal {
+    type Err = rust_decimal::Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        rust_decimal::Decimal::from_str_exact(s).map(Self)
+    }
+}
+
+impl From<i64> for Decimal {
+    fn from(value: i64) -> Self {
+        Self(rust_decimal::Decimal::from(value))
+    }
+}
+
+impl TryFrom<f64> for Decimal {
+    type Error = ();
+
+    /// Attempts to convert a Decimal to a float.
+    ///
+    /// This can fail if the float is infinite or NaN, or otherwise cannot be
+    /// represented by a decimal number.
+    fn try_from(value: f64) -> Result<Self, Self::Error> {
+        rust_decimal::Decimal::from_f64_retain(value).map(Self).ok_or(())
+    }
+}
+
+impl TryFrom<Decimal> for f64 {
+    type Error = rust_decimal::Error;
+
+    /// Attempts to convert a Decimal to a float.
+    ///
+    /// This should in principle be infallible according to the implementation,
+    /// but we mirror the decimal implementation's API either way.
+    fn try_from(value: Decimal) -> Result<Self, Self::Error> {
+        value.0.try_into()
+    }
+}
+
+impl TryFrom<Decimal> for i64 {
+    type Error = rust_decimal::Error;
+
+    /// Attempts to convert a Decimal to an integer.
+    ///
+    /// Returns an error if the decimal has a fractional part, or if there
+    /// would be overflow or underflow.
+    fn try_from(value: Decimal) -> Result<Self, Self::Error> {
+        value.0.try_into()
+    }
+}
+
+impl Display for Decimal {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        if self.0.is_sign_negative() {
+            f.write_str(repr::MINUS_SIGN)?;
+        }
+        self.0.abs().fmt(f)
+    }
+}
+
+impl Repr for Decimal {
+    fn repr(&self) -> EcoString {
+        eco_format!("decimal({})", eco_format!("{}", self.0).repr())
+    }
+}
+
+impl Neg for Decimal {
+    type Output = Self;
+
+    fn neg(self) -> Self {
+        Self(-self.0)
+    }
+}
+
+/// A value that can be cast to a decimal.
+pub enum ToDecimal {
+    /// A string with the decimal's representation.
+    Str(EcoString),
+    /// An integer to be converted to the equivalent decimal.
+    Int(i64),
+    /// A float to be converted to the equivalent decimal.
+    Float(f64),
+}
+
+cast! {
+    ToDecimal,
+    v: i64 => Self::Int(v),
+    v: f64 => Self::Float(v),
+    v: Str => Self::Str(EcoString::from(v)),
+}
diff --git a/crates/typst/src/foundations/float.rs b/crates/typst/src/foundations/float.rs
index ff3e62a5..8318641a 100644
--- a/crates/typst/src/foundations/float.rs
+++ b/crates/typst/src/foundations/float.rs
@@ -4,7 +4,7 @@ use ecow::{eco_format, EcoString};
 
 use crate::diag::StrResult;
 use crate::foundations::{
-    bail, cast, func, repr, scope, ty, Bytes, Endianness, Repr, Str,
+    bail, cast, func, repr, scope, ty, Bytes, Decimal, Endianness, Repr, Str,
 };
 use crate::layout::Ratio;
 
@@ -177,6 +177,7 @@ cast! {
     v: f64 => Self(v),
     v: bool => Self(v as i64 as f64),
     v: i64 => Self(v as f64),
+    v: Decimal => Self(f64::try_from(v).map_err(|_| eco_format!("invalid float: {}", v))?),
     v: Ratio => Self(v.get()),
     v: Str => Self(
         parse_float(v.clone().into())
diff --git a/crates/typst/src/foundations/int.rs b/crates/typst/src/foundations/int.rs
index 79a8a86f..1f29c2a6 100644
--- a/crates/typst/src/foundations/int.rs
+++ b/crates/typst/src/foundations/int.rs
@@ -4,7 +4,7 @@ use ecow::{eco_format, EcoString};
 
 use crate::diag::StrResult;
 use crate::foundations::{
-    bail, cast, func, repr, scope, ty, Bytes, Cast, Repr, Str, Value,
+    bail, cast, func, repr, scope, ty, Bytes, Cast, Decimal, Repr, Str, Value,
 };
 
 /// A whole number.
@@ -33,16 +33,19 @@ type i64;
 
 #[scope]
 impl i64 {
-    /// Converts a value to an integer.
+    /// Converts a value to an integer. Raises an error if there is an attempt
+    /// to produce an integer larger than the maximum 64-bit signed integer
+    /// or smaller than the minimum 64-bit signed integer.
     ///
     /// - Booleans are converted to `0` or `1`.
-    /// - Floats are floored to the next 64-bit integer.
+    /// - Floats and decimals are truncated to the next 64-bit integer.
     /// - Strings are parsed in base 10.
     ///
     /// ```example
     /// #int(false) \
     /// #int(true) \
     /// #int(2.7) \
+    /// #int(decimal("3.8")) \
     /// #(int("27") + int("4"))
     /// ```
     #[func(constructor)]
@@ -360,10 +363,19 @@ cast! {
     ToInt,
     v: i64 => Self(v),
     v: bool => Self(v as i64),
-    v: f64 => Self(v as i64),
+    v: f64 => Self(convert_float_to_int(v)?),
+    v: Decimal => Self(i64::try_from(v).map_err(|_| eco_format!("number too large"))?),
     v: Str => Self(parse_int(&v).map_err(|_| eco_format!("invalid integer: {}", v))?),
 }
 
+fn convert_float_to_int(f: f64) -> StrResult<i64> {
+    if f <= i64::MIN as f64 - 1.0 || f >= i64::MAX as f64 + 1.0 {
+        Err(eco_format!("number too large"))
+    } else {
+        Ok(f as i64)
+    }
+}
+
 fn parse_int(mut s: &str) -> Result<i64, ParseIntError> {
     let mut sign = 1;
     if let Some(rest) = s.strip_prefix('-').or_else(|| s.strip_prefix(repr::MINUS_SIGN)) {
diff --git a/crates/typst/src/foundations/mod.rs b/crates/typst/src/foundations/mod.rs
index 2e1f5c82..dc939932 100644
--- a/crates/typst/src/foundations/mod.rs
+++ b/crates/typst/src/foundations/mod.rs
@@ -15,6 +15,7 @@ mod cast;
 mod content;
 mod context;
 mod datetime;
+mod decimal;
 mod dict;
 mod duration;
 mod element;
@@ -43,6 +44,7 @@ pub use self::cast::*;
 pub use self::content::*;
 pub use self::context::*;
 pub use self::datetime::*;
+pub use self::decimal::*;
 pub use self::dict::*;
 pub use self::duration::*;
 pub use self::element::*;
@@ -105,6 +107,7 @@ pub(super) fn define(global: &mut Scope, inputs: Dict) {
     global.define_type::<Regex>();
     global.define_type::<Selector>();
     global.define_type::<Datetime>();
+    global.define_type::<Decimal>();
     global.define_type::<Duration>();
     global.define_type::<Version>();
     global.define_type::<Plugin>();
diff --git a/crates/typst/src/foundations/str.rs b/crates/typst/src/foundations/str.rs
index 61116d85..6091fb2e 100644
--- a/crates/typst/src/foundations/str.rs
+++ b/crates/typst/src/foundations/str.rs
@@ -11,8 +11,8 @@ use unicode_segmentation::UnicodeSegmentation;
 use crate::diag::{bail, At, SourceResult, StrResult};
 use crate::engine::Engine;
 use crate::foundations::{
-    cast, dict, func, repr, scope, ty, Array, Bytes, Context, Dict, Func, IntoValue,
-    Label, Repr, Type, Value, Version,
+    cast, dict, func, repr, scope, ty, Array, Bytes, Context, Decimal, Dict, Func,
+    IntoValue, Label, Repr, Type, Value, Version,
 };
 use crate::layout::Alignment;
 use crate::syntax::{Span, Spanned};
@@ -775,6 +775,7 @@ cast! {
     ToStr,
     v: i64 => Self::Int(v),
     v: f64 => Self::Str(repr::display_float(v).into()),
+    v: Decimal => Self::Str(format_str!("{}", v)),
     v: Version => Self::Str(format_str!("{}", v)),
     v: Bytes => Self::Str(
         std::str::from_utf8(&v)
diff --git a/crates/typst/src/foundations/value.rs b/crates/typst/src/foundations/value.rs
index 78769900..cabe5647 100644
--- a/crates/typst/src/foundations/value.rs
+++ b/crates/typst/src/foundations/value.rs
@@ -12,9 +12,10 @@ use serde::{Deserialize, Deserializer, Serialize, Serializer};
 use crate::diag::{HintedStrResult, HintedString, StrResult};
 use crate::eval::ops;
 use crate::foundations::{
-    fields, repr, Args, Array, AutoValue, Bytes, CastInfo, Content, Datetime, Dict,
-    Duration, Fold, FromValue, Func, IntoValue, Label, Module, NativeElement, NativeType,
-    NoneValue, Plugin, Reflect, Repr, Resolve, Scope, Str, Styles, Type, Version,
+    fields, repr, Args, Array, AutoValue, Bytes, CastInfo, Content, Datetime, Decimal,
+    Dict, Duration, Fold, FromValue, Func, IntoValue, Label, Module, NativeElement,
+    NativeType, NoneValue, Plugin, Reflect, Repr, Resolve, Scope, Str, Styles, Type,
+    Version,
 };
 use crate::layout::{Abs, Angle, Em, Fr, Length, Ratio, Rel};
 use crate::symbols::Symbol;
@@ -65,6 +66,8 @@ pub enum Value {
     Label(Label),
     /// A datetime
     Datetime(Datetime),
+    /// A decimal value: `decimal("123.4500")`
+    Decimal(Decimal),
     /// A duration
     Duration(Duration),
     /// A content value: `[*Hi* there]`.
@@ -136,6 +139,7 @@ impl Value {
             Self::Bytes(_) => Type::of::<Bytes>(),
             Self::Label(_) => Type::of::<Label>(),
             Self::Datetime(_) => Type::of::<Datetime>(),
+            Self::Decimal(_) => Type::of::<Decimal>(),
             Self::Duration(_) => Type::of::<Duration>(),
             Self::Content(_) => Type::of::<Content>(),
             Self::Styles(_) => Type::of::<Styles>(),
@@ -204,6 +208,7 @@ impl Value {
             Self::None => Content::empty(),
             Self::Int(v) => TextElem::packed(repr::format_int_with_base(v, 10)),
             Self::Float(v) => TextElem::packed(repr::display_float(v)),
+            Self::Decimal(v) => TextElem::packed(eco_format!("{v}")),
             Self::Str(v) => TextElem::packed(v),
             Self::Version(v) => TextElem::packed(eco_format!("{v}")),
             Self::Symbol(v) => TextElem::packed(v.get()),
@@ -248,6 +253,7 @@ impl Debug for Value {
             Self::Bytes(v) => Debug::fmt(v, f),
             Self::Label(v) => Debug::fmt(v, f),
             Self::Datetime(v) => Debug::fmt(v, f),
+            Self::Decimal(v) => Debug::fmt(v, f),
             Self::Duration(v) => Debug::fmt(v, f),
             Self::Content(v) => Debug::fmt(v, f),
             Self::Styles(v) => Debug::fmt(v, f),
@@ -285,6 +291,7 @@ impl Repr for Value {
             Self::Bytes(v) => v.repr(),
             Self::Label(v) => v.repr(),
             Self::Datetime(v) => v.repr(),
+            Self::Decimal(v) => v.repr(),
             Self::Duration(v) => v.repr(),
             Self::Content(v) => v.repr(),
             Self::Styles(v) => v.repr(),
@@ -337,6 +344,7 @@ impl Hash for Value {
             Self::Content(v) => v.hash(state),
             Self::Styles(v) => v.hash(state),
             Self::Datetime(v) => v.hash(state),
+            Self::Decimal(v) => v.hash(state),
             Self::Duration(v) => v.hash(state),
             Self::Array(v) => v.hash(state),
             Self::Dict(v) => v.hash(state),
@@ -645,6 +653,7 @@ primitive! {
 primitive! { Bytes: "bytes", Bytes }
 primitive! { Label: "label", Label }
 primitive! { Datetime: "datetime", Datetime }
+primitive! { Decimal: "decimal", Decimal }
 primitive! { Duration: "duration", Duration }
 primitive! { Content: "content",
     Content,
diff --git a/tests/ref/decimal-display-round.png b/tests/ref/decimal-display-round.png
new file mode 100644
index 00000000..506a5b88
--- /dev/null
+++ b/tests/ref/decimal-display-round.png
diff --git a/tests/ref/decimal-display.png b/tests/ref/decimal-display.png
new file mode 100644
index 00000000..9109b195
--- /dev/null
+++ b/tests/ref/decimal-display.png
diff --git a/tests/ref/float-repr.png b/tests/ref/float-repr.png
deleted file mode 100644
index e73ee328..00000000
--- a/tests/ref/float-repr.png
+++ /dev/null
diff --git a/tests/ref/int-repr.png b/tests/ref/int-repr.png
deleted file mode 100644
index a2ee4ee0..00000000
--- a/tests/ref/int-repr.png
+++ /dev/null
diff --git a/tests/suite/foundations/calc.typ b/tests/suite/foundations/calc.typ
index e702be9f..18cfa484 100644
--- a/tests/suite/foundations/calc.typ
+++ b/tests/suite/foundations/calc.typ
@@ -1,6 +1,21 @@
 --- calc-round ---
 #test(calc.round(calc.e, digits: 2), 2.72)
 #test(calc.round(calc.pi, digits: 2), 3.14)
+#test(type(calc.round(3.1415, digits: 2)), float)
+#test(type(calc.round(5, digits: 2)), int)
+#test(type(calc.round(decimal("3.1415"), digits: 2)), decimal)
+
+--- calc-round-large-inputs ---
+#test(calc.round(31114, digits: 4000000000), 31114)
+#test(calc.round(9223372036854775807, digits: 12), 9223372036854775807)
+#test(calc.round(238959235.129590203, digits: 4000000000), 238959235.129590203)
+#test(calc.round(1.7976931348623157e+308, digits: 12), 1.7976931348623157e+308)
+#test(calc.round(decimal("238959235.129590203"), digits: 4000000000), decimal("238959235.129590203"))
+#test(calc.round(decimal("79228162514264337593543950335"), digits: 12), decimal("79228162514264337593543950335"))
+
+--- calc-round-negative-digits ---
+// Error: 29-31 number must be at least zero
+#calc.round(243.32, digits: -2)
 
 --- calc-abs ---
 // Test the `abs` function.
@@ -11,9 +26,11 @@
 #test(calc.abs(-3.14), 3.14)
 #test(calc.abs(50%), 50%)
 #test(calc.abs(-25%), 25%)
+#test(calc.abs(decimal("4932.493249324932")), decimal("4932.493249324932"))
+#test(calc.abs(decimal("-12402.593295932041")), decimal("12402.593295932041"))
 
---- cals-abs-bad-type ---
-// Error: 11-22 expected integer, float, length, angle, ratio, or fraction, found string
+--- calc-abs-bad-type ---
+// Error: 11-22 expected integer, float, length, angle, ratio, fraction, or decimal, found string
 #calc.abs("no number")
 
 --- calc-even-and-odd ---
@@ -30,6 +47,13 @@
 #test(calc.rem(5, -3), 2)
 #test(calc.rem(22.5, 10), 2.5)
 #test(calc.rem(9, 4.5), 0)
+#test(calc.rem(decimal("5"), -3), decimal("2"))
+#test(calc.rem(decimal("22.5"), decimal("10")), decimal("2.5"))
+#test(calc.rem(9, decimal("4.5")), decimal("0"))
+#test(calc.rem(decimal("7"), decimal("3")), decimal("1"))
+#test(calc.rem(decimal("7"), decimal("-3")), decimal("1"))
+#test(calc.rem(decimal("-7"), decimal("3")), decimal("-1"))
+#test(calc.rem(decimal("-7"), decimal("-3")), decimal("-1"))
 
 --- calc-rem-divisor-zero-1 ---
 // Error: 14-15 divisor must not be zero
@@ -39,6 +63,10 @@
 // Error: 16-19 divisor must not be zero
 #calc.rem(3.0, 0.0)
 
+--- calc-rem-divisor-zero-3 ---
+// Error: 27-39 divisor must not be zero
+#calc.rem(decimal("4.0"), decimal("0"))
+
 --- calc-div-euclid ---
 // Test the `div-euclid` function.
 #test(calc.div-euclid(7, 3), 2)
@@ -46,6 +74,11 @@
 #test(calc.div-euclid(-7, 3), -3)
 #test(calc.div-euclid(-7, -3), 3)
 #test(calc.div-euclid(2.5, 2), 1)
+#test(calc.div-euclid(decimal("7"), decimal("3")), decimal("2"))
+#test(calc.div-euclid(decimal("7"), decimal("-3")), decimal("-2"))
+#test(calc.div-euclid(decimal("-7"), decimal("3")), decimal("-3"))
+#test(calc.div-euclid(decimal("-7"), decimal("-3")), decimal("3"))
+#test(calc.div-euclid(decimal("2.5"), decimal("2")), decimal("1"))
 
 --- calc-div-euclid-divisor-zero-1 ---
 // Error: 21-22 divisor must not be zero
@@ -55,6 +88,10 @@
 // Error: 23-26 divisor must not be zero
 #calc.div-euclid(3.0, 0.0)
 
+--- calc-div-euclid-divisor-zero-3 ---
+// Error: 35-50 divisor must not be zero
+#calc.div-euclid(decimal("3.00"), decimal("0.00"))
+
 --- calc-rem-euclid ---
 // Test the `rem-euclid` function.
 #test(calc.rem-euclid(7, 3), 1)
@@ -62,6 +99,11 @@
 #test(calc.rem-euclid(-7, 3), 2)
 #test(calc.rem-euclid(-7, -3), 2)
 #test(calc.rem-euclid(2.5, 2), 0.5)
+#test(calc.rem-euclid(decimal("7"), decimal("3")), decimal("1"))
+#test(calc.rem-euclid(decimal("7"), decimal("-3")), decimal("1"))
+#test(calc.rem-euclid(decimal("-7"), decimal("3")), decimal("2"))
+#test(calc.rem-euclid(decimal("-7"), decimal("-3")), decimal("2"))
+#test(calc.rem-euclid(decimal("2.5"), decimal("2")), decimal("0.5"))
 
 --- calc-rem-euclid-divisor-zero-1 ---
 // Error: 21-22 divisor must not be zero
@@ -71,13 +113,19 @@
 // Error: 23-26 divisor must not be zero
 #calc.rem-euclid(3.0, 0.0)
 
+--- calc-rem-euclid-divisor-zero-3 ---
+// Error: 35-50 divisor must not be zero
+#calc.rem-euclid(decimal("3.00"), decimal("0.00"))
+
 --- calc-quo ---
 // Test the `quo` function.
 #test(calc.quo(1, 1), 1)
 #test(calc.quo(5, 3), 1)
 #test(calc.quo(5, -3), -1)
-#test(calc.quo(22.5, 10), 2)
-#test(calc.quo(9, 4.5), 2)
+#test(calc.quo(22.5, 10), 2.0)
+#test(calc.quo(9, 4.5), 2.0)
+#test(calc.quo(decimal("22.5"), 10), decimal("2"))
+#test(calc.quo(decimal("9"), decimal("4.5")), decimal("2"))
 
 --- calc-quo-divisor-zero-1 ---
 // Error: 14-15 divisor must not be zero
@@ -87,17 +135,24 @@
 // Error: 16-19 divisor must not be zero
 #calc.quo(3.0, 0.0)
 
+--- calc-quo-divisor-zero-3 ---
+// Error: 27-41 divisor must not be zero
+#calc.quo(decimal("4.0"), decimal("0.0"))
+
 --- calc-min-and-max ---
 // Test the `min` and `max` functions.
 #test(calc.min(2, -4), -4)
 #test(calc.min(3.5, 1e2, -0.1, 3), -0.1)
+#test(calc.min(decimal("3.5"), 4, decimal("-3213.99999")), decimal("-3213.99999"))
 #test(calc.max(-3, 11), 11)
+#test(calc.max(decimal("3"), 45), 45)
 #test(calc.min("hi"), "hi")
 
 --- calc-pow-log-exp-ln ---
 // Test the `pow`, `log`, `exp`, and `ln` functions.
 #test(calc.pow(10, 0), 1)
 #test(calc.pow(2, 4), 16)
+#test(calc.pow(decimal("0.5"), 18), decimal("0.000003814697265625"))
 #test(calc.exp(2), calc.pow(calc.e, 2))
 #test(calc.ln(10), calc.log(10, base: calc.e))
 
@@ -156,6 +211,10 @@
 // Error: 2-25 the result is too large
 #calc.pow(2, 2147483647)
 
+--- calc-pow-too-large-decimal ---
+// Error: 2-56 the result is too large
+#calc.pow(decimal("2222222222222222222222222222"), 100)
+
 --- calc-pow-bad-exponent ---
 // Error: 14-36 exponent may not be infinite, subnormal, or NaN
 #calc.pow(2, calc.pow(2.0, 10000.0))
@@ -248,6 +307,30 @@
 // Error: 2-41 the result is too large
 #calc.lcm(15486487489457, 4874879896543)
 
+--- calc-rounding-larger-than-max-int ---
+#test(calc.round(decimal("9223372036854775809.5")), decimal("9223372036854775810"))
+#test(calc.round(9223372036854775809.5), 9223372036854775810.0)
+#test(calc.floor(decimal("9223372036854775809.5")), decimal("9223372036854775809"))
+#test(calc.floor(9223372036854775809.5), 9223372036854775809.0)
+#test(calc.ceil(decimal("9223372036854775809.5")), decimal("9223372036854775810"))
+#test(calc.ceil(9223372036854775809.5), 9223372036854775810.0)
+#test(calc.trunc(decimal("9223372036854775809.5")), decimal("9223372036854775809"))
+#test(calc.trunc(9223372036854775809.5), 9223372036854775809.0)
+#test(calc.quo(decimal("9223372036854775809.5"), 1), decimal("9223372036854775809"))
+#test(calc.quo(9223372036854775809.5, 1), 9223372036854775809.0)
+
+--- calc-rounding-smaller-than-min-int ---
+#test(calc.round(decimal("-9223372036854775809.5")), decimal("-9223372036854775810"))
+#test(calc.round(-9223372036854775809.5), -9223372036854775810.0)
+#test(calc.floor(decimal("-9223372036854775809.5")), decimal("-9223372036854775810"))
+#test(calc.floor(-9223372036854775809.5), -9223372036854775810.0)
+#test(calc.ceil(decimal("-9223372036854775809.5")), decimal("-9223372036854775809"))
+#test(calc.ceil(-9223372036854775809.5), -9223372036854775809.0)
+#test(calc.trunc(decimal("-9223372036854775809.5")), decimal("-9223372036854775809"))
+#test(calc.trunc(-9223372036854775809.5), -9223372036854775809.0)
+#test(calc.quo(decimal("-9223372036854775809.5"), 1), decimal("-9223372036854775810"))
+#test(calc.quo(-9223372036854775809.5, 1), -9223372036854775810.0)
+
 --- calc-min-nothing ---
 // Error: 2-12 expected at least one value
 #calc.min()
@@ -259,3 +342,8 @@
 --- calc-max-uncomparable ---
 // Error: 16-19 cannot compare 1pt with 1em
 #calc.max(1em, 1pt)
+
+--- calc-clamp-decimal-float ---
+// Error: 2-37 cannot apply this operation to a decimal and a float
+// Hint: 2-37 if loss of precision is acceptable, explicitly cast the decimal to a float with `float(value)`
+#calc.clamp(decimal("10"), 5.5, 6.6)
diff --git a/tests/suite/foundations/decimal.typ b/tests/suite/foundations/decimal.typ
new file mode 100644
index 00000000..d5fd9444
--- /dev/null
+++ b/tests/suite/foundations/decimal.typ
@@ -0,0 +1,79 @@
+--- decimal-constructor ---
+#test(decimal(10), decimal("10.0"))
+#test(decimal("-7654.321"), decimal("-7654.321"))
+#test(decimal("\u{2212}7654.321"), decimal("-7654.321"))
+#test(decimal({ 3.141592653 }), decimal("3.141592653000000012752934707"))
+#test(decimal({ -3.141592653 }), decimal("-3.141592653000000012752934707"))
+#test(type(decimal(10)), decimal)
+
+--- decimal-constructor-bad-type ---
+// Error: 10-17 expected integer, float, or string, found type
+#decimal(decimal)
+
+--- decimal-constructor-bad-value ---
+// Error: 10-17 invalid decimal: 1.2.3
+#decimal("1.2.3")
+
+--- decimal-constructor-float-literal ---
+// Warning: 18-25 creating a decimal using imprecise float literal
+// Hint: 18-25 use a string in the decimal constructor to avoid loss of precision: `decimal("1.32523")`
+#let _ = decimal(1.32523)
+
+--- decimal-constructor-float-inf ---
+// Error: 10-19 float is not a valid decimal: float.inf
+#decimal(float.inf)
+
+--- decimal-constructor-float-negative-inf ---
+// Error: 10-20 float is not a valid decimal: -float.inf
+#decimal(-float.inf)
+
+--- decimal-constructor-float-nan ---
+// Error: 10-19 float is not a valid decimal: float.nan
+#decimal(float.nan)
+
+--- decimal-repr ---
+// Test the `repr` function with decimals.
+#test(repr(decimal("12.0")), "decimal(\"12.0\")")
+#test(repr(decimal("3.14")), "decimal(\"3.14\")")
+#test(repr(decimal("1234567890.0")), "decimal(\"1234567890.0\")")
+#test(repr(decimal("0123456789.0")), "decimal(\"123456789.0\")")
+#test(repr(decimal("0.0")), "decimal(\"0.0\")")
+#test(repr(decimal("-0.0")), "decimal(\"0.0\")")
+#test(repr(decimal("-1.0")), "decimal(\"-1.0\")")
+#test(repr(decimal("-9876543210.0")), "decimal(\"-9876543210.0\")")
+#test(repr(decimal("-0987654321.0")), "decimal(\"-987654321.0\")")
+#test(repr(decimal("-3.14")), "decimal(\"-3.14\")")
+#test(repr(decimal("-3.9191919191919191919191919195")), "decimal(\"-3.9191919191919191919191919195\")")
+#test(repr(decimal("5.0000000000")), "decimal(\"5.0000000000\")")
+#test(repr(decimal("4.0") - decimal("8.0")), "decimal(\"-4.0\")")
+
+--- decimal-display ---
+// Test decimals.
+#set page(width: auto)
+#decimal("12.0") \
+#decimal("3.14") \
+#decimal("1234567890.0") \
+#decimal("0123456789.0") \
+#decimal("0.0") \
+#decimal("-0.0") \
+#decimal("-1.0") \
+#decimal("-9876543210.0") \
+#decimal("-0987654321.0") \
+#decimal("-3.14") \
+#decimal("-3.9191919191919191919191919195") \
+#decimal("5.0000000000") \
+#(decimal("4.0") - decimal("8.0"))
+
+--- decimal-display-round ---
+// Display less digits.
+#calc.round(decimal("-3.9191919191919191919191919195"), digits: 4) \
+#calc.round(decimal("5.0000000000"), digits: 4)
+
+--- decimal-expected-float-error ---
+// Error: 11-25 expected integer, float, or angle, found decimal
+// Hint: 11-25 if loss of precision is acceptable, explicitly cast the decimal to a float with `float(value)`
+#calc.sin(decimal("1.1"))
+
+--- decimal-expected-integer-error ---
+// Error: 11-25 expected integer, found decimal
+#calc.odd(decimal("1.1"))
diff --git a/tests/suite/foundations/float.typ b/tests/suite/foundations/float.typ
index 67d4acbf..2e9e07f2 100644
--- a/tests/suite/foundations/float.typ
+++ b/tests/suite/foundations/float.typ
@@ -6,10 +6,14 @@
 #test(float("3.1415"), 3.1415)
 #test(float("-7654.321"), -7654.321)
 #test(float("\u{2212}7654.321"), -7654.321)
+#test(float(decimal("4.89")), 4.89)
+#test(float(decimal("3.1234567891234567891234567891")), 3.123456789123457)
+#test(float(decimal("79228162514264337593543950335")), 79228162514264340000000000000.0)
+#test(float(decimal("-79228162514264337593543950335")), -79228162514264340000000000000.0)
 #test(type(float(10)), float)
 
 --- float-constructor-bad-type ---
-// Error: 8-13 expected float, boolean, integer, ratio, or string, found type
+// Error: 8-13 expected float, boolean, integer, decimal, ratio, or string, found type
 #float(float)
 
 --- float-constructor-bad-value ---
@@ -55,20 +59,20 @@
 
 --- float-repr ---
 // Test the `repr` function with floats.
-#repr(12.0) \
-#repr(3.14) \
-#repr(1234567890.0) \
-#repr(0123456789.0) \
-#repr(0.0) \
-#repr(-0.0) \
-#repr(-1.0) \
-#repr(-9876543210.0) \
-#repr(-0987654321.0) \
-#repr(-3.14) \
-#repr(4.0 - 8.0) \
-#repr(float.inf) \
-#repr(-float.inf) \
-#repr(float.nan)
+#test(repr(12.0), "12.0")
+#test(repr(3.14), "3.14")
+#test(repr(1234567890.0), "1234567890.0")
+#test(repr(0123456789.0), "123456789.0")
+#test(repr(0.0), "0.0")
+#test(repr(-0.0), "-0.0")
+#test(repr(-1.0), "-1.0")
+#test(repr(-9876543210.0), "-9876543210.0")
+#test(repr(-0987654321.0), "-987654321.0")
+#test(repr(-3.14), "-3.14")
+#test(repr(4.0 - 8.0), "-4.0")
+#test(repr(float.inf), "float.inf")
+#test(repr(-float.inf), "-float.inf")
+#test(repr(float.nan), "float.nan")
 
 --- float-display ---
 // Test floats.
diff --git a/tests/suite/foundations/int.typ b/tests/suite/foundations/int.typ
index 1744ef88..9cb27cf5 100644
--- a/tests/suite/foundations/int.typ
+++ b/tests/suite/foundations/int.typ
@@ -21,15 +21,34 @@
 #test(int("-834"), -834)
 #test(int("\u{2212}79"), -79)
 #test(int(10 / 3), 3)
+#test(int(-58.34), -58)
+#test(int(decimal("92492.193848921")), 92492)
+#test(int(decimal("-224.342211")), -224)
 
 --- int-constructor-bad-type ---
-// Error: 6-10 expected integer, boolean, float, or string, found length
+// Error: 6-10 expected integer, boolean, float, decimal, or string, found length
 #int(10pt)
 
 --- int-constructor-bad-value ---
 // Error: 6-12 invalid integer: nope
 #int("nope")
 
+--- int-constructor-float-too-large ---
+// Error: 6-27 number too large
+#int(9223372036854775809.5)
+
+--- int-constructor-float-too-large-min ---
+// Error: 6-28 number too large
+#int(-9223372036854775809.5)
+
+--- int-constructor-decimal-too-large ---
+// Error: 6-38 number too large
+#int(decimal("9223372036854775809.5"))
+
+--- int-constructor-decimal-too-large-min ---
+// Error: 6-39 number too large
+#int(decimal("-9223372036854775809.5"))
+
 --- int-signum ---
 // Test int `signum()`
 #test(int(0).signum(), 0)
@@ -58,15 +77,15 @@
 
 --- int-repr ---
 // Test the `repr` function with integers.
-#repr(12) \
-#repr(1234567890) \
-#repr(0123456789) \
-#repr(0) \
-#repr(-0) \
-#repr(-1) \
-#repr(-9876543210) \
-#repr(-0987654321) \
-#repr(4 - 8)
+#test(repr(12), "12")
+#test(repr(1234567890), "1234567890")
+#test(repr(0123456789), "123456789")
+#test(repr(0), "0")
+#test(repr(-0), "0")
+#test(repr(-1), "-1")
+#test(repr(-9876543210), "-9876543210")
+#test(repr(-0987654321), "-987654321")
+#test(repr(4 - 8), "-4")
 
 --- int-display ---
 // Test integers.
diff --git a/tests/suite/foundations/str.typ b/tests/suite/foundations/str.typ
index 025ec53d..0da11c31 100644
--- a/tests/suite/foundations/str.typ
+++ b/tests/suite/foundations/str.typ
@@ -23,6 +23,24 @@
 #test(str(-3.14), "−3.14")
 #test(str(4.0 - 8.0), "−4")
 
+--- str-from-decimal ---
+// Test the `str` function with decimals.
+#test(str(decimal("12")), "12")
+#test(str(decimal("12.0")), "12.0")
+#test(str(decimal("3.14")), "3.14")
+#test(str(decimal("1234567890.0")), "1234567890.0")
+#test(str(decimal("0123456789.0")), "123456789.0")
+#test(str(decimal("0.0")), "0.0")
+#test(str(decimal("-0.0")), "0.0")
+#test(str(decimal("-1.0")), "−1.0")
+#test(str(decimal("-9876543210.0")), "−9876543210.0")
+#test(str(decimal("-0987654321.0")), "−987654321.0")
+#test(str(decimal("-3.14")), "−3.14")
+#test(str(decimal("-3.9191919191919191919191919195")), "−3.9191919191919191919191919195")
+#test(str(decimal("5.0000000000")), "5.0000000000")
+#test(str(decimal("4.0") - decimal("8.0")), "−4.0")
+#test(str(decimal("4") - decimal("8")), "−4")
+
 --- str-from-int ---
 // Test the `str` function with integers.
 #test(str(12), "12")
@@ -36,7 +54,7 @@
 #test(str(4 - 8), "−4")
 
 --- str-constructor-bad-type ---
-// Error: 6-8 expected integer, float, version, bytes, label, type, or string, found content
+// Error: 6-8 expected integer, float, decimal, version, bytes, label, type, or string, found content
 #str([])
 
 --- str-constructor-bad-base ---
diff --git a/tests/suite/scripting/ops.typ b/tests/suite/scripting/ops.typ
index e0c94e02..d17c0117 100644
--- a/tests/suite/scripting/ops.typ
+++ b/tests/suite/scripting/ops.typ
@@ -8,7 +8,7 @@
 // Test math operators.
 
 // Test plus and minus.
-#for v in (1, 3.14, 12pt, 45deg, 90%, 13% + 10pt, 6.3fr) {
+#for v in (1, 3.14, decimal("12.43"), 12pt, 45deg, 90%, 13% + 10pt, 6.3fr) {
   // Test plus.
   test(+v, v)
 
@@ -60,6 +60,7 @@
 // Mathematical identities.
 #let nums = (
   1, 3.14,
+  decimal("12.45"),
   12pt, 3em, 12pt + 3em,
   45deg,
   90%,
@@ -76,12 +77,12 @@
   test(v - v, 0 * v)
   test(v + v, 2 * v)
 
-  // Integer addition does not give a float.
-  if type(v) != int {
+  // Integer or decimal addition does not give a float.
+  if type(v) not in (int, decimal) {
     test(v + v, 2.0 * v)
   }
 
-  if type(v) != relative and ("pt" not in repr(v) or "em" not in repr(v)) {
+  if type(v) not in (relative, decimal) and ("pt" not in repr(v) or "em" not in repr(v)) {
     test(v / v, 1.0)
   }
 }
@@ -112,6 +113,46 @@
   }
 }
 
+--- ops-binary-decimal ---
+// Addition.
+#test(decimal("40.1") + decimal("13.2"), decimal("53.3"))
+#test(decimal("12.34330") + decimal("45.96670"), decimal("58.31000"))
+#test(decimal("451113.111111111111111111111") + decimal("23.222222222222222222324"), decimal("451136.333333333333333333435"))
+
+// Subtraction.
+#test(decimal("40.1") - decimal("13.2"), decimal("26.9"))
+#test(decimal("12.34330") - decimal("45.96670"), decimal("-33.62340"))
+#test(decimal("1234.111111111111111111111") - decimal("0.222222222222222222324"), decimal("1233.888888888888888888787"))
+
+// Multiplication.
+#test(decimal("40.5") * decimal("9.5"), decimal("384.75"))
+#test(decimal("-0.1234567890123456789012345678") * decimal("-2.0"), decimal("0.2469135780246913578024691356"))
+
+// Division.
+#test(decimal("1.0") / decimal("7.0"), decimal("0.1428571428571428571428571429"))
+#test(decimal("9999991.6666") / decimal("3.0"), decimal("3333330.5555333333333333333333"))
+#test(decimal("3253452.4034029359598214312040") / decimal("-49293591.4039493929532"), decimal("-0.0660015290170614346071165643"))
+
+--- ops-binary-decimal-int ---
+// Operations between decimal and integer.
+#test(decimal("2359.123456789123456789001234") + 2, decimal("2361.123456789123456789001234"))
+#test(decimal("2359.123456789123456789001234") - 2, decimal("2357.123456789123456789001234"))
+#test(decimal("2359.123456789123456789001234") * 2, decimal("4718.246913578246913578002468"))
+#test(decimal("2359.123456789123456789001234") / 2, decimal("1179.561728394561728394500617"))
+
+--- ops-binary-decimal-multiplication-division-imprecision ---
+// Test digit truncation by multiplication and division.
+#test(decimal("0.7777777777777777777777777777") / 1000, decimal("0.0007777777777777777777777778"))
+#test(decimal("0.7777777777777777777777777777") * decimal("0.001"), decimal("0.0007777777777777777777777778"))
+
+--- ops-add-too-large-decimal ---
+// Error: 3-47 value is too large
+#(decimal("79228162514264337593543950335") + 1)
+
+--- ops-subtract-too-large-decimal ---
+// Error: 3-48 value is too large
+#(decimal("-79228162514264337593543950335") - 1)
+
 --- ops-multiply-inf-with-length ---
 // Test that multiplying infinite numbers by certain units does not crash.
 #(float("inf") * 1pt)
@@ -164,6 +205,8 @@
 #test((:) == (a: 1), false)
 #test((a: 2 - 1.0, b: 2) == (b: 2, a: 1), true)
 #test("a" != "a", false)
+#test(decimal("1.234") == decimal("1.23400000000"), true)
+#test(235 == decimal("235.0"), true)
 
 // Functions compare by identity.
 #test(test == test, true)
@@ -202,6 +245,10 @@
 #test(() >= (), true)
 #test(() <= (1,), true)
 #test((1,) <= (), false)
+#test(decimal("123.0000000000000000000000001") > decimal("123.0"), true)
+#test(decimal("123.5") < decimal("122.444"), false)
+#test(decimal("459.9999999999999999999999999") < 460, true)
+#test(decimal("128.50") > 460, false)
 
 --- ops-in ---
 // Test `in` operator.