From b2572f9d48a8f0efd30014302dcc271cd89fa91e Mon Sep 17 00:00:00 2001
From: Laurenz <laurmaedje@gmail.com>
Date: Tue, 6 Dec 2022 15:37:17 +0100
Subject: [PATCH] Math shorthands

---
 src/model/eval.rs            |   1 +
 src/syntax/ast.rs            |   5 +++++
 src/syntax/parsing.rs        |   1 +
 src/syntax/tokens.rs         |  12 ++++++++++++
 tests/ref/math/shorthand.png | Bin 0 -> 1230 bytes
 tests/typ/math/shorthand.typ |   4 ++++
 6 files changed, 23 insertions(+)
 create mode 100644 tests/ref/math/shorthand.png
 create mode 100644 tests/typ/math/shorthand.typ

diff --git a/src/model/eval.rs b/src/model/eval.rs
index a32b0cd2..f3281dac 100644
--- a/src/model/eval.rs
+++ b/src/model/eval.rs
@@ -424,6 +424,7 @@ impl Eval for ast::MathNode {
             Self::Space(_) => (vm.items.space)(),
             Self::Linebreak(v) => v.eval(vm)?,
             Self::Escape(v) => (vm.items.math_atom)(v.get().into()),
+            Self::Shorthand(v) => (vm.items.math_atom)(v.get().into()),
             Self::Atom(v) => v.eval(vm)?,
             Self::Symbol(v) => (vm.items.symbol)(v.get().clone()),
             Self::Script(v) => v.eval(vm)?,
diff --git a/src/syntax/ast.rs b/src/syntax/ast.rs
index 55586feb..3661c156 100644
--- a/src/syntax/ast.rs
+++ b/src/syntax/ast.rs
@@ -441,6 +441,9 @@ pub enum MathNode {
     Linebreak(Linebreak),
     /// An escape sequence: `\#`, `\u{1F5FA}`.
     Escape(Escape),
+    /// A shorthand for a unicode codepoint. For example, `->` for a right
+    /// arrow.
+    Shorthand(Shorthand),
     /// An atom: `x`, `+`, `12`.
     Atom(Atom),
     /// Symbol notation: `:arrow:l:` or `arrow:l`. Notations without any colons
@@ -464,6 +467,7 @@ impl AstNode for MathNode {
             SyntaxKind::Space { .. } => node.cast().map(Self::Space),
             SyntaxKind::Linebreak => node.cast().map(Self::Linebreak),
             SyntaxKind::Escape(_) => node.cast().map(Self::Escape),
+            SyntaxKind::Shorthand(_) => node.cast().map(Self::Shorthand),
             SyntaxKind::Atom(_) => node.cast().map(Self::Atom),
             SyntaxKind::Symbol(_) => node.cast().map(Self::Symbol),
             SyntaxKind::Script => node.cast().map(Self::Script),
@@ -479,6 +483,7 @@ impl AstNode for MathNode {
             Self::Space(v) => v.as_untyped(),
             Self::Linebreak(v) => v.as_untyped(),
             Self::Escape(v) => v.as_untyped(),
+            Self::Shorthand(v) => v.as_untyped(),
             Self::Atom(v) => v.as_untyped(),
             Self::Symbol(v) => v.as_untyped(),
             Self::Script(v) => v.as_untyped(),
diff --git a/src/syntax/parsing.rs b/src/syntax/parsing.rs
index 5bd5e63b..97570950 100644
--- a/src/syntax/parsing.rs
+++ b/src/syntax/parsing.rs
@@ -442,6 +442,7 @@ fn math_primary(p: &mut Parser) {
         | SyntaxKind::Linebreak
         | SyntaxKind::Escape(_)
         | SyntaxKind::Str(_)
+        | SyntaxKind::Shorthand(_)
         | SyntaxKind::Symbol(_) => p.eat(),
 
         // Atoms.
diff --git a/src/syntax/tokens.rs b/src/syntax/tokens.rs
index 57188096..ff6a1a96 100644
--- a/src/syntax/tokens.rs
+++ b/src/syntax/tokens.rs
@@ -439,6 +439,18 @@ impl Tokens<'_> {
 impl Tokens<'_> {
     fn math(&mut self, start: usize, c: char) -> SyntaxKind {
         match c {
+            // Symbol shorthands.
+            '|' if self.s.eat_if("->") => SyntaxKind::Shorthand('\u{21A6}'),
+            '<' if self.s.eat_if("->") => SyntaxKind::Shorthand('\u{2194}'),
+            '<' if self.s.eat_if("=>") => SyntaxKind::Shorthand('\u{21D4}'),
+            '!' if self.s.eat_if('=') => SyntaxKind::Shorthand('\u{2260}'),
+            '<' if self.s.eat_if('=') => SyntaxKind::Shorthand('\u{2264}'),
+            '>' if self.s.eat_if('=') => SyntaxKind::Shorthand('\u{2265}'),
+            '<' if self.s.eat_if('-') => SyntaxKind::Shorthand('\u{2190}'),
+            '-' if self.s.eat_if('>') => SyntaxKind::Shorthand('\u{2192}'),
+            '=' if self.s.eat_if('>') => SyntaxKind::Shorthand('\u{21D2}'),
+            ':' if self.s.eat_if('=') => SyntaxKind::Shorthand('\u{2254}'),
+
             // Multi-char things.
             '#' => self.hash(start),
 
diff --git a/tests/ref/math/shorthand.png b/tests/ref/math/shorthand.png
new file mode 100644
index 0000000000000000000000000000000000000000..4b14006bd34ded381b544ba41de383f80482cab0
GIT binary patch
literal 1230
zcmV;<1Tp)GP)<h;3K|Lk000e1NJLTq009I5002-300000+6z>J000D)Nkl<Zc-rll
zZA@EL7{_mLXmG|XE;Gb9Ge4LZoHGP76_sW}abql*LUn80CI%@%hXNDEh8xHS*aC=w
zSkw%}4U@g7TLuxGf@7JJ;zTmX3WEaS<!%YEwKPCq|K_%}Jr{1-KyF>)^Z(F$&$;)U
z`<!2&mvb-2kw_#Gi9{liNVh5c&qNRi0zn`M1c4wB1cE>i2m(PM2n2y35Cnoi5C{T6
z_-`OM(u#LmXZ7Ap(`Zsp0x+d%G#}i0mI{qa?-w>N-m;SCwVZziq2ld^U<u35tZwC#
zS^#uyj_kknEEAt)@g=$X`iJ%;m==jaQ*yvO!SP^iPl;XPLaf4OjvfVYIQMqu8A(OX
z6`<}5{nkZ-5Ze<l2$zENerzbuL`Nck6Z^#%j1#WIkhquEAV&{e*@<_0=YFEo&-n~p
zcq4E*p?0am4}{_L@1QN64dK<_gkSSoqZEX(WK=iJ`9PzZY2@ns-nZ#;pdg&jdtpUh
z@jorImS-VYV+~O2W<sdW^MvenDF|Kr9NTPcloXdtPoFH!==1iBZeT9|u+yJq?Fj(B
zDQrQncCS`m2vdCIoBX)fE4bY(1oSH{#%QA$!iiPQ=iJ(u?wkc-XnjHKY4-MPb7E1B
z9$&AKh5*H1ek@a61TKHt6M9rTh44C=!(n-q?|i(_AcBBX??R_O&Ooqc#btVxw1F2x
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zCs-PtAJ6YiZ65k^VZ%(zUdQ+|&cJ<7I2dGzY?q0_bol}YW(W7>9}eJ0m6p_xs$_G7
z{sj&kz9;EvdjKK8Y{H$V9o*;ijq%cxR)RoZn+XCzAP5A3AP@wCKoAH5K_CbOfglhB
sf<O=m0ztSlAdpBT5{X12kw_By8@3$PHZN!8DF6Tf07*qoM6N<$f?N(S8~^|S

literal 0
HcmV?d00001

diff --git a/tests/typ/math/shorthand.typ b/tests/typ/math/shorthand.typ
new file mode 100644
index 00000000..d37c938f
--- /dev/null
+++ b/tests/typ/math/shorthand.typ
@@ -0,0 +1,4 @@
+// Test math shorthands.
+
+---
+$ f : NN <=> RR, n |-> sqrt(n) $