Fix scanner missing the o. operator

demo/test-cases.html

@@ -92,6 +92,7 @@ <h2>Operators</h2>
         <test-case>ı.^\^</test-case>
         <test-case>x.^ \(n)</test-case>
         <test-case>&lt;&lt;&lt; [] &gt;&gt;&gt;</test-case>
+        <test-case>a o. b</test-case>
 
         <test-case display="block">
           \`lim sup`._(n -> oo)

src/compiler/tokenizer/scanners/alpha.js

@@ -30,8 +30,8 @@ export default function alphaScanner(char, input, { start, grouping }) {
     [nextChar] = input.slice(i);
   }
 
-  // alpha may contain a period, but not never end with one.
-  if (value.endsWith(".")) {
+  // alpha may contain a period, but only known ops can end with one.
+  if (value.endsWith(".") && !KNOWN_OPS.has(value)) {
     value = value.slice(0, -1);
   }
 

src/compiler/tokenizer/scanners/alpha.test.js

@@ -138,6 +138,24 @@ test("can’t end with a period", (t) => {
   t.is(token?.split, true);
 });
 
+test("unless it is a known operator", (t) => {
+  const token = alpha("o", "o.", { start: 0, grouping: false });
+
+  t.is(token?.type, "operator");
+  t.is(token?.value, "⊙");
+  t.is(token?.end, 2);
+  t.falsy(token?.split);
+});
+
+test("known operator ends in period cannot be followed by an alphanum", (t) => {
+  const token = alpha("o", "o.o", { start: 0, grouping: false });
+
+  t.is(token?.type, "ident");
+  t.is(token?.value, "o");
+  t.is(token?.end, 1);
+  t.is(token?.split, true);
+});
+
 test("known prefix", (t) => {
   const token = alpha("h", "hat a", { start: 0, grouping: false });
 

src/compiler/tokenizer/scanners/operator.test.js

@@ -30,6 +30,14 @@ test("known operator", (t) => {
   t.is(token?.end, 3);
 });
 
+test("known operator that ends with a period", (t) => {
+  const token = operator("o.", " o. b", { start: 1, grouping: false });
+
+  t.is(token?.type, "operator");
+  t.is(token?.value, "⊙");
+  t.is(token?.end, 3);
+});
+
 test("emits the longest possible known operator", (t) => {
   const token = operator("^", "^^^ 1", { start: 0, grouping: false });
 

test/operators.js

@@ -33,6 +33,12 @@ test("i hat", (t) => {
   t.snapshot(render("ı.^\\^"));
 });
 
+test("circumpunct", (t) => {
+  t.is(render("o."), "<math><mo>⊙</mo></math>");
+  t.snapshot(render("a o. b"));
+  t.snapshot(render("a o.b"));
+});
+
 test("Norm of two parallel lines", (t) => {
   t.snapshot(render("||a || b||"));
 });

test/snapshots/operators.js.md

@@ -36,6 +36,16 @@ Generated by [AVA](https://avajs.dev).
 
     '<math><mover><mi>ı</mi><mo>^</mo></mover></math>'
 
+## circumpunct
+
+> Snapshot 1
+
+    '<math><mi>a</mi><mo>⊙</mo><mi>b</mi></math>'
+
+> Snapshot 2
+
+    '<math><mi>a</mi><mrow><mi>o</mi><mo>.</mo><mi>b</mi></mrow></math>'
+
 ## Norm of two parallel lines
 
 > Snapshot 1