Fix calc.inf, -calc.inf, and calc.nan reprs and displays (#4724)

crates/typst/src/foundations/repr.rs

@@ -73,12 +73,15 @@ pub fn format_int_with_base(mut n: i64, base: i64) -> EcoString {
 }
 
 /// Converts a float to a string representation with a specific precision and a
-/// suffix, all with a single allocation.
+/// unit, all with a single allocation.
+///
+/// The returned string is always valid Typst code. As such, it might not be a
+/// float literal. For example, it may return `"calc.inf"`.
 pub fn format_float(
     mut value: f64,
     precision: Option<u8>,
     force_separator: bool,
-    suffix: &str,
+    unit: &str,
 ) -> EcoString {
     if let Some(p) = precision {
         let offset = 10_f64.powi(p as i32);
@@ -86,12 +89,16 @@ pub fn format_float(
     }
     // Debug for f64 always prints a decimal separator, while Display only does
     // when necessary.
+    let unit_multiplication = if unit.is_empty() { "" } else { " * 1" };
     if value.is_nan() {
-        "NaN".into()
+        eco_format!("calc.nan{unit_multiplication}{unit}")
+    } else if value.is_infinite() {
+        let sign = if value < 0.0 { "-" } else { "" };
+        eco_format!("{sign}calc.inf{unit_multiplication}{unit}")
     } else if force_separator {
-        eco_format!("{:?}{}", value, suffix)
+        eco_format!("{value:?}{unit}")
     } else {
-        eco_format!("{}{}", value, suffix)
+        eco_format!("{value}{unit}")
     }
 }
 
@@ -112,6 +119,9 @@ pub fn format_float_with_unit(value: f64, unit: &str) -> EcoString {
 pub fn display_float(value: f64) -> EcoString {
     if value.is_nan() {
         "NaN".into()
+    } else if value.is_infinite() {
+        let sign = if value < 0.0 { MINUS_SIGN } else { "" };
+        eco_format!("{sign}∞")
     } else if value < 0.0 {
         eco_format!("{}{}", MINUS_SIGN, value.abs())
     } else {

tests/suite/foundations/float.typ

@@ -20,6 +20,8 @@
 // Test float `is-nan()`.
 #test(float(calc.nan).is-nan(), true)
 #test(float(10).is-nan(), false)
+#test(float(calc.inf).is-nan(), false)
+#test(float(-calc.inf).is-nan(), false)
 
 --- float-is-infinite ---
 // Test float `is-infinite()`.
@@ -27,6 +29,7 @@
 #test(float(-calc.inf).is-infinite(), true)
 #test(float(10).is-infinite(), false)
 #test(float(-10).is-infinite(), false)
+#test(float(calc.nan).is-infinite(), false)
 
 --- float-signum ---
 // Test float `signum()`
@@ -35,6 +38,8 @@
 #test(float(-1.0).signum(), -1.0)
 #test(float(10.0).signum(), 1.0)
 #test(float(-10.0).signum(), -1.0)
+#test(float(calc.inf).signum(), 1.0)
+#test(float(-calc.inf).signum(), -1.0)
 #test(float(calc.nan).signum().is-nan(), true)
 
 --- float-repr ---
@@ -49,7 +54,10 @@
 #repr(-9876543210.0) \
 #repr(-0987654321.0) \
 #repr(-3.14) \
-#repr(4.0 - 8.0)
+#repr(4.0 - 8.0) \
+#repr(calc.inf) \
+#repr(-calc.inf) \
+#repr(calc.nan)
 
 --- float-display ---
 // Test floats.
@@ -63,4 +71,7 @@
 #(-9876543210.0) \
 #(-0987654321.0) \
 #(-3.14) \
-#(4.0 - 8.0)
+#(4.0 - 8.0) \
+#calc.inf \
+#(-calc.inf) \
+#calc.nan

tests/suite/scripting/ops.typ

@@ -335,7 +335,7 @@
 #(1em <= 10pt)
 
 --- ops-compare-normal-float-with-nan ---
-// Error: 3-22 cannot compare 2.2 with NaN
+// Error: 3-22 cannot compare 2.2 with calc.nan
 #(2.2 <= float("nan"))
 
 --- ops-compare-int-and-str ---
@@ -343,7 +343,7 @@
 #((0, 1, 3) > (0, 1, "a"))
 
 --- ops-compare-array-nested-failure ---
-// Error: 3-42 cannot compare 3.5 with NaN
+// Error: 3-42 cannot compare 3.5 with calc.nan
 #((0, "a", 3.5) <= (0, "a", float("nan")))
 
 --- ops-divide-by-zero-float ---