Don't automatically match fences

Fixes #306

crates/typst-syntax/src/parser.rs

@@ -282,7 +282,7 @@ fn math_expr_prec(p: &mut Parser, min_prec: usize, stop: SyntaxKind) {
                 math_class(p.current_text()),
                 None | Some(MathClass::Alphabetic)
             );
-            if !maybe_delimited(p, true) {
+            if !maybe_delimited(p) {
                 p.eat();
             }
         }
@@ -321,7 +321,7 @@ fn math_expr_prec(p: &mut Parser, min_prec: usize, stop: SyntaxKind) {
     if continuable
         && min_prec < 3
         && p.prev_end() == p.current_start()
-        && maybe_delimited(p, false)
+        && maybe_delimited(p)
     {
         p.wrap(m, SyntaxKind::Math);
     }
@@ -397,29 +397,20 @@ fn math_expr_prec(p: &mut Parser, min_prec: usize, stop: SyntaxKind) {
     }
 }
 
-fn maybe_delimited(p: &mut Parser, allow_fence: bool) -> bool {
-    if allow_fence && math_class(p.current_text()) == Some(MathClass::Fence) {
-        math_delimited(p, MathClass::Fence);
-        true
-    } else if math_class(p.current_text()) == Some(MathClass::Opening) {
-        math_delimited(p, MathClass::Closing);
-        true
-    } else {
-        false
+fn maybe_delimited(p: &mut Parser) -> bool {
+    let open = math_class(p.current_text()) == Some(MathClass::Opening);
+    if open {
+        math_delimited(p);
     }
+    open
 }
 
-fn math_delimited(p: &mut Parser, stop: MathClass) {
+fn math_delimited(p: &mut Parser) {
     let m = p.marker();
     p.eat();
     let m2 = p.marker();
     while !p.eof() && !p.at(SyntaxKind::Dollar) {
-        let class = math_class(p.current_text());
-        if stop == MathClass::Fence && class == Some(MathClass::Closing) {
-            break;
-        }
-
-        if class == Some(stop) {
+        if math_class(p.current_text()) == Some(MathClass::Closing) {
             p.wrap(m2, SyntaxKind::Math);
             p.eat();
             p.wrap(m, SyntaxKind::MathDelimited);

tests/typ/math/attach-p2.typ

@@ -23,5 +23,5 @@ $ (-1)^n + (1/2 + 3)^(-1/2) $
 $ x_1 p_1 frak(p)_1 2_1 dot_1 lg_1 !_1 \\_1 ]_1 "ip"_1 op("iq")_1 \
   x^1 b^1 frak(b)^1 2^1 dot^1 lg^1 !^1 \\^1 ]^1 "ib"^1 op("id")^1 \
   x_1 y_1 "_"_1 x^1 l^1 "`"^1 attach(I,tl:1,bl:1,tr:1,br:1)
-  scripts(sum)_1^1 integral_1^1 |1/2|_1^1 \
+  scripts(sum)_1^1 integral_1^1 abs(1/2)_1^1 \
   x^1_1, "("b y")"^1_1 != (b y)^1_1, "[∫]"_1 [integral]_1 $

tests/typ/math/delimited.typ

@@ -2,8 +2,8 @@
 
 ---
 // Test automatic matching.
-$ (a) + {b/2} + |a|/2 + (b) $
-$f(x/2) < zeta(c^2 + |a + b/2|)$
+$ (a) + {b/2} + abs(a)/2 + (b) $
+$f(x/2) < zeta(c^2 + abs(a + b/2))$
 
 ---
 // Test unmatched.
@@ -17,7 +17,7 @@ $ lr(| ]1,2\[ + 1/2|) $
 ---
 // Test fence confusion.
 $ |x + |y| + z/a| \
-  |x + lr(|y|) + z/a| $
+  lr(|x + |y| + z/a|) $
 
 ---
 // Test that symbols aren't matched automatically.

tests/typ/math/spacing.typ

@@ -4,7 +4,7 @@
 // Test spacing cases.
 $ä, +, c, (, )$ \
 $=), (+), {times}$
-$⟧<⟦, |-|, [=$ \
+$⟧<⟦, abs(-), [=$ \
 $a=b, a==b$ \
 $-a, +a$ \
 $a not b$ \