fix: stop single-line string rules at line ends

src/grammars/assembly.js

@@ -22,8 +22,8 @@ export default {
     },
     strings: {
       patterns: [
-        { match: "'(?:\\\\.|[^'\\\\])*'", name: "string.quoted.single" },
-        { match: "\"(?:\\\\.|[^\"\\\\])*\"", name: "string.quoted.double" }
+        { match: "'(?:\\\\.|[^'\\\\\\r\\n])*'", name: "string.quoted.single" },
+        { match: "\"(?:\\\\.|[^\"\\\\\\r\\n])*\"", name: "string.quoted.double" }
       ]
     },
     "label-declaration": {

src/grammars/c.js

@@ -28,7 +28,7 @@ export default {
           name: "keyword.control.directive.include",
           patterns: [
             { match: "<[^>]*>", name: "string.quoted.other.lt-gt" },
-            { match: "\"(?:\\\\.|[^\"\\\\])*\"", name: "string.quoted.double" }
+            { match: "\"(?:\\\\.|[^\"\\\\\\r\\n])*\"", name: "string.quoted.double" }
           ]
         },
         {
@@ -39,8 +39,8 @@ export default {
     },
     strings: {
       patterns: [
-        { match: "'(?:\\\\.|[^'\\\\])'", name: "string.quoted.char" },
-        { match: "\"(?:\\\\.|[^\"\\\\])*\"", name: "string.quoted.double" }
+        { match: "'(?:\\\\.|[^'\\\\\\r\\n])'", name: "string.quoted.char" },
+        { match: "\"(?:\\\\.|[^\"\\\\\\r\\n])*\"", name: "string.quoted.double" }
       ]
     },
     "storage-types": {

src/grammars/csharp.js

@@ -26,9 +26,9 @@ export default {
         { match: "@\"(?:\"\"|[^\"])*\"", name: "string.quoted.double.verbatim" },
         { match: "\\$@\"(?:\"\"|\\{\\{|\\}\\}|[^\"])*\"", name: "string.quoted.double.interpolated" },
         { match: "@\\$\"(?:\"\"|\\{\\{|\\}\\}|[^\"])*\"", name: "string.quoted.double.interpolated" },
-        { match: "\\$\"(?:\\\\.|\\{\\{|\\}\\}|[^\"\\\\])*\"", name: "string.quoted.double.interpolated" },
-        { match: "\"(?:\\\\.|[^\"\\\\])*\"", name: "string.quoted.double" },
-        { match: "'(?:\\\\.|[^'\\\\])'", name: "string.quoted.char" }
+        { match: "\\$\"(?:\\\\.|\\{\\{|\\}\\}|[^\"\\\\\\r\\n])*\"", name: "string.quoted.double.interpolated" },
+        { match: "\"(?:\\\\.|[^\"\\\\\\r\\n])*\"", name: "string.quoted.double" },
+        { match: "'(?:\\\\.|[^'\\\\\\r\\n])'", name: "string.quoted.char" }
       ]
     },
     attributes: { match: "\\[[A-Za-z_][\\w.]*\\]", name: "entity.name.decorator" },

src/grammars/css.js

@@ -11,7 +11,7 @@ export default {
   ],
   repository: {
     comments: { begin: "/\\*", end: "\\*/", name: "comment.block" },
-    strings: { match: "(['\"])(?:\\\\.|(?!\\1)[^\\\\])*\\1", name: "string.quoted" },
+    strings: { match: "(['\"])(?:\\\\.|(?!\\1)[^\\\\\\r\\n])*\\1", name: "string.quoted" },
     keyframes: {
       begin: "(@(?:-\\w+-)?keyframes)\\s+([a-zA-Z_-][\\w-]*)\\s*\\{",
       end: "\\}",
@@ -22,7 +22,7 @@ export default {
       patterns: [{ include: "$self" }]
     },
     "at-rule-block": {
-      begin: "(@(?:container|document|font-feature-values|layer|media|scope|starting-style|supports)\\b)[^{;]*\\{",
+      begin: "(@(?:container|counter-style|document|font-face|font-feature-values|font-palette-values|layer|media|page|position-try|scope|starting-style|supports|view-transition)\\b)[^{;]*\\{",
       end: "\\}",
       beginCaptures: { 1: { name: "keyword.control.at-rule" } },
       patterns: [{ include: "$self" }]
@@ -38,7 +38,7 @@ export default {
       ]
     },
     "rule-set": {
-      begin: "([^\\s@{};<][^@{};<;]*?)\\s*\\{",
+      begin: "([^\\s@{};<][^@{};<]*?)\\s*\\{",
       end: "\\}",
       beginCaptures: { 1: { name: "entity.name.selector" } },
       patterns: [

src/grammars/dart.js

@@ -25,8 +25,8 @@ export default {
       patterns: [
         { begin: "r?\"\"\"", end: "\"\"\"", name: "string.quoted.triple.double" },
         { begin: "r?'''", end: "'''", name: "string.quoted.triple.single" },
-        { match: "r?\"(?:\\\\.|[^\"\\\\])*\"", name: "string.quoted.double" },
-        { match: "r?'(?:\\\\.|[^'\\\\])*'", name: "string.quoted.single" }
+        { match: "r?\"(?:\\\\.|[^\"\\\\\\r\\n])*\"", name: "string.quoted.double" },
+        { match: "r?'(?:\\\\.|[^'\\\\\\r\\n])*'", name: "string.quoted.single" }
       ]
     },
     annotations: { match: "@[A-Za-z_][\\w]*", name: "entity.name.decorator" },

src/grammars/graphql.js

@@ -19,7 +19,7 @@ export default {
     strings: {
       patterns: [
         { begin: "\"\"\"", end: "\"\"\"", name: "string.quoted.triple" },
-        { match: "\"(?:\\\\.|[^\"\\\\])*\"", name: "string.quoted.double" }
+        { match: "\"(?:\\\\.|[^\"\\\\\\r\\n])*\"", name: "string.quoted.double" }
       ]
     },
     "type-declaration": {

src/grammars/java.js

@@ -23,8 +23,8 @@ export default {
     strings: {
       patterns: [
         { begin: "\"\"\"", end: "\"\"\"", name: "string.quoted.triple" },
-        { match: "\"(?:\\\\.|[^\"\\\\])*\"", name: "string.quoted.double" },
-        { match: "'(?:\\\\.|[^'\\\\])'", name: "string.quoted.char" }
+        { match: "\"(?:\\\\.|[^\"\\\\\\r\\n])*\"", name: "string.quoted.double" },
+        { match: "'(?:\\\\.|[^'\\\\\\r\\n])'", name: "string.quoted.char" }
       ]
     },
     annotations: { match: "@[A-Za-z_][\\w.]*", name: "entity.name.decorator" },

src/grammars/kotlin.js

@@ -23,8 +23,8 @@ export default {
     strings: {
       patterns: [
         { begin: "\"\"\"", end: "\"\"\"", name: "string.quoted.triple" },
-        { match: "\"(?:\\\\.|[^\"\\\\])*\"", name: "string.quoted.double" },
-        { match: "'(?:\\\\.|[^'\\\\])'", name: "string.quoted.char" }
+        { match: "\"(?:\\\\.|[^\"\\\\\\r\\n])*\"", name: "string.quoted.double" },
+        { match: "'(?:\\\\.|[^'\\\\\\r\\n])'", name: "string.quoted.char" }
       ]
     },
     annotations: { match: "@[A-Za-z_][\\w.]*", name: "entity.name.decorator" },

src/grammars/lua.js

@@ -21,8 +21,8 @@ export default {
     strings: {
       patterns: [
         { begin: "\\[(=*)\\[", end: "\\]\\1\\]", name: "string.quoted.other.multiline" },
-        { match: "\"(?:\\\\.|[^\"\\\\])*\"", name: "string.quoted.double" },
-        { match: "'(?:\\\\.|[^'\\\\])*'", name: "string.quoted.single" }
+        { match: "\"(?:\\\\.|[^\"\\\\\\r\\n])*\"", name: "string.quoted.double" },
+        { match: "'(?:\\\\.|[^'\\\\\\r\\n])*'", name: "string.quoted.single" }
       ]
     },
     "function-declaration": {

src/grammars/swift.js

@@ -23,7 +23,7 @@ export default {
     strings: {
       patterns: [
         { begin: "\"\"\"", end: "\"\"\"", name: "string.quoted.triple" },
-        { match: "\"(?:\\\\.|[^\"\\\\])*\"", name: "string.quoted.double" }
+        { match: "\"(?:\\\\.|[^\"\\\\\\r\\n])*\"", name: "string.quoted.double" }
       ]
     },
     attributes: { match: "@[A-Za-z_][\\w]*", name: "entity.name.decorator" },

src/grammars/toml.js

@@ -25,7 +25,7 @@ export default {
       patterns: [
         { begin: "\"\"\"", end: "\"\"\"", name: "string.quoted.triple.double" },
         { begin: "'''", end: "'''", name: "string.quoted.triple.single" },
-        { match: "\"(?:\\\\.|[^\"\\\\])*\"", name: "string.quoted.double" },
+        { match: "\"(?:\\\\.|[^\"\\\\\\r\\n])*\"", name: "string.quoted.double" },
         { match: "'[^'\\r\\n]*'", name: "string.quoted.single" }
       ]
     },

src/grammars/yaml.js

@@ -6,7 +6,9 @@ export default {
     { match: "^(?:---|\\.\\.\\.)\\s*$|^%YAML\\b.*$", name: "keyword.control.document" },
     { match: "^\\s*(?:-\\s+)?([^#\\s][^\\r\\n:#]*?)(?=\\s*:)", captures: { 1: { name: "entity.name.key" } } },
     { match: "[&*][a-zA-Z_][\\w-]*|![^\\s]+", name: "entity.name.anchor" },
-    { match: "(['\"])(?:\\\\.|(?!\\1)[^\\\\])*\\1", name: "string.quoted" },
+    // Quoted scalars may fold over lines, but only onto more-indented ones, so
+    // a stray apostrophe in a plain scalar cannot swallow the rest of the file.
+    { match: "(['\"])(?:\\\\.|(?!\\1)[^\\\\\\r\\n]|\\r?\\n[ \\t]+)*\\1", name: "string.quoted" },
     { match: "(?<=:\\s)[|>][-+]?\\s*$", name: "keyword.control.block-scalar" },
     { match: "\\b(?:true|false|yes|no|on|off)\\b", name: "constant.language.boolean" },
     { match: "\\bnull\\b|~", name: "constant.language" },

test/highlight.spec.pw.js

@@ -24,6 +24,33 @@ const readHighlights = page =>
     };
   });
 
+/**
+ * Highlight a single injected code block and read back its ranges by category.
+ */
+const highlightSnippet = (page, language, code) =>
+  page.evaluate(async ({ language, code }) => {
+    const root = document.createElement("div");
+    const block = document.createElement("code");
+    const pre = document.createElement("pre");
+    block.className = `language-${language}`;
+    block.textContent = code;
+    pre.append(block);
+    root.append(pre);
+    document.body.append(root);
+
+    const { highlightAll } = await import("/docs/microlighter/index.js");
+    await highlightAll({ root });
+
+    const ranges = {};
+    for (const [category, highlight] of CSS.highlights) {
+      for (const range of highlight) {
+        if (range.startContainer.parentElement !== block) continue;
+        (ranges[category] ??= []).push(range.toString());
+      }
+    }
+    return ranges;
+  }, { language, code });
+
 test.describe("MicroLighter demo site (docs/index.html)", () => {
   test("registers highlight ranges across every code block", async ({ page }) => {
     await page.goto(HOMEPAGE, { waitUntil: "networkidle" });
@@ -231,6 +258,81 @@ test.describe("MicroLighter demo site (docs/index.html)", () => {
     expect(sampleLanguages).toEqual(["html", "markdown", "python", "sql", "cpp", "tsx"]);
   });
 
+  test("stops unterminated quotes from swallowing later lines", async ({ page }) => {
+    await page.goto(HOMEPAGE, { waitUntil: "networkidle" });
+
+    const css = await highlightSnippet(page, "css", [
+      "a { font-family: Don't; }",
+      'b { content: "kept"; }',
+      "c { font-family: Won't; }"
+    ].join("\n"));
+    const yaml = await highlightSnippet(page, "yaml", [
+      "first: don't",
+      'second: "kept"',
+      "third: won't"
+    ].join("\n"));
+
+    expect(css.string).toEqual(['"kept"']);
+    expect(yaml.string).toEqual(['"kept"']);
+  });
+
+  test("terminates single-line string literals at the end of the line", async ({ page }) => {
+    await page.goto(HOMEPAGE, { waitUntil: "networkidle" });
+
+    // Languages whose grammars only allow multi-line strings through a
+    // dedicated triple-quoted or long-bracket rule.
+    const languages = [
+      "assembly", "c", "csharp", "css", "dart", "graphql",
+      "java", "kotlin", "lua", "swift", "toml"
+    ];
+    const unexpected = {};
+
+    for (const language of languages) {
+      const ranges = await highlightSnippet(page, language, 'first = \'x\nsecond = "kept"\nthird = \'y\'\n');
+      const strings = ranges.string ?? [];
+      if (!strings.includes('"kept"') || strings.some(value => value.includes("\n"))) {
+        unexpected[language] = strings;
+      }
+    }
+
+    expect(unexpected).toEqual({});
+  });
+
+  test("keeps highlighting yaml quoted scalars folded over several lines", async ({ page }) => {
+    await page.goto(HOMEPAGE, { waitUntil: "networkidle" });
+
+    const ranges = await highlightSnippet(page, "yaml", 'key: "folded\n  continuation"\nnext: 1\n');
+
+    expect(ranges.string).toEqual(['"folded\n  continuation"']);
+  });
+
+  test("categorizes block at-rules as at-rule keywords, not selectors", async ({ page }) => {
+    await page.goto(HOMEPAGE, { waitUntil: "networkidle" });
+
+    const ranges = await highlightSnippet(page, "css", [
+      '@font-face { font-family: "Example"; }',
+      "@page { margin: 1cm; }",
+      "@counter-style thumbs { system: cyclic; }",
+      "@view-transition { navigation: auto; }"
+    ].join("\n"));
+
+    expect(ranges["at-rule"]).toEqual([
+      "@font-face",
+      "@page",
+      "@counter-style",
+      "@view-transition"
+    ]);
+    expect(ranges.selector ?? []).toEqual([]);
+  });
+
+  test("scopes multi-line selectors without their trailing whitespace", async ({ page }) => {
+    await page.goto(HOMEPAGE, { waitUntil: "networkidle" });
+
+    const ranges = await highlightSnippet(page, "css", "a,\nb\n{\n  color: red;\n}\n");
+
+    expect(ranges.selector).toEqual(["a,\nb"]);
+  });
+
   test("highlights a large stylesheet without pathological rescanning", async ({ page }) => {
     await page.goto(HOMEPAGE, { waitUntil: "networkidle" });