Newton's notation for derivatives (#281)

library/src/symbols/sym.rs

@@ -88,7 +88,17 @@ pub(crate) const SYM: &[(&'static str, Symbol)] = symbols! {
         circle: '⊝',
         wave.double: '〰',
     ],
-    dot: ['.', op: '⋅', c: '·', circle: '⊙', circle.big: '⨀', square: '⊡'],
+    dot: [
+        '.',
+        op: '⋅',
+        c: '·',
+        circle: '⊙',
+        circle.big: '⨀',
+        square: '⊡',
+        double: '¨',
+        triple: '\u{20db}',
+        quad: '\u{20dc}',
+    ],
     excl: ['!', double: '‼', inv: '¡', quest: '⁉'],
     quest: ['?', double: '⁇', excl: '⁈', inv: '¿'],
     interrobang: '‽',

src/eval/symbol.rs

@@ -114,6 +114,8 @@ impl Symbol {
             '\u{0306}' | '˘' => '\u{0306}',
             '\u{0307}' | '.' | '˙' | '⋅' => '\u{0307}',
             '\u{0308}' | '¨' => '\u{0308}',
+            '\u{20db}' => '\u{20db}',
+            '\u{20dc}' => '\u{20dc}',
             '\u{030a}' | '∘' | '○' => '\u{030a}',
             '\u{030b}' | '˝' => '\u{030b}',
             '\u{030c}' | 'ˇ' => '\u{030c}',

tests/typ/math/accent.typ

@@ -5,6 +5,10 @@
 $grave(a), acute(b), hat(f), tilde(§), macron(ä), diaer(a), ä \
  breve(\&), dot(!), circle(a), caron(@), arrow(Z), arrow.l(Z)$
 
+---
+
+$ x &= p \ dot(x) &= v \ dot.double(x) &= a \ dot.triple(x) &= j \ dot.quad(x) &= s $
+
 ---
 // Test `accent` function.
 $accent(ö, .), accent(v, <-), accent(ZZ, \u{0303})$