release: Vs Code New Extension with layout Support

editors/vscode/language-configuration.json

@@ -46,7 +46,7 @@
   "folding": {
     "offSide": false,
     "markers": {
-      "start": "^\\s*(?:page|component|api|middleware|realtime|view|seo|props|functions)\\b.*\\{\\s*$",
+      "start": "^\\s*(?:page|component|layout|api|middleware|realtime|view|seo|props|functions)\\b.*\\{\\s*$",
       "end": "^\\s*\\}\\s*$"
     }
   }

editors/vscode/package.json

@@ -2,7 +2,7 @@
   "name": "wrnexus",
   "displayName": "WRNexus Language Support",
   "description": "Syntax highlighting, formatting, diagnostics, snippets and completions for WrNexus .wrn files.",
-  "version": "0.2.4",
+  "version": "0.2.5",
   "publisher": "wrnexus",
   "private": true,
   "license": "SEE LICENSE IN LICENSE",

editors/vscode/snippets/wrn.json

@@ -56,6 +56,20 @@
     ]
   },
 
+  "WRN layout": {
+    "prefix": ["wrn-layout", "layout"],
+    "description": "Create a WRN layout",
+    "body": [
+      "layout ${1:LayoutName} {",
+      "    view {",
+      "        <main>",
+      "            {content}",
+      "        </main>",
+      "    }",
+      "}"
+    ]
+  },
+
   "WRN state": {
     "prefix": ["wrn-state", "state"],
     "description": "Create reactive state",

editors/vscode/src/compiler.cjs

@@ -274,10 +274,10 @@ function parse(source) {
   };
   try {
     const opener = lx.next();
-    if (opener.type !== "ident" || opener.value !== "page" && opener.value !== "component") {
-      throw new ParseError(`Expected 'page' or 'component' but got '${opener.value || opener.type}' at offset ${opener.pos}`);
+    if (opener.type !== "ident" || !["page", "component", "layout"].includes(opener.value)) {
+      throw new ParseError(`Expected 'page', 'component', or 'layout' but got '${opener.value || opener.type}' at offset ${opener.pos}`);
     }
-    const kind = opener.value === "component" ? "component" : "page";
+    const kind = opener.value;
     const name = expect("ident").value;
     expect("lbrace");
     let layout;
@@ -448,12 +448,12 @@ function parse(source) {
 function parseHtmlView(src, pos) {
   let i = pos;
   const isNameStart = (c) => /[A-Za-z_]/.test(c);
-  const isNamePart = (c) => /[A-Za-z0-9_:.[\]%-]/.test(c);
+  const isTagNamePart = (c) => /[A-Za-z0-9_$:.-]/.test(c);
   const isAttributeNamePart = (c, next) => {
     if (c === "/") {
       return next !== ">";
     }
-    return isNamePart(c);
+    return /[A-Za-z0-9_$:.[\]%-]/.test(c);
   };
   const isWs2 = (c) => c === " " || c === "\t" || c === `
 ` || c === "\r";
@@ -491,9 +491,21 @@ function parseHtmlView(src, pos) {
     i++;
     return value;
   };
-  const readName = () => {
-    if (i >= src.length || !isNameStart(src[i]))
-      return fail("Expected a tag or attribute name");
+  const readTagName = () => {
+    if (i >= src.length || !isNameStart(src[i])) {
+      return fail("Expected a tag name");
+    }
+    const start = i++;
+    while (i < src.length && isTagNamePart(src[i])) {
+      i++;
+    }
+    return src.slice(start, i);
+  };
+  const readAttributeName = () => {
+    const first = src[i];
+    if (i >= src.length || !isNameStart(first) && first !== ":" && first !== "$") {
+      return fail("Expected an attribute name");
+    }
     const start = i++;
     while (i < src.length && isAttributeNamePart(src[i], src[i + 1])) {
       i++;
@@ -502,7 +514,7 @@ function parseHtmlView(src, pos) {
   };
   const parseTag = () => {
     i++;
-    const tag = readName();
+    const tag = readTagName();
     const attrs = [];
     for (;; ) {
       skipWs();
@@ -519,7 +531,7 @@ function parseHtmlView(src, pos) {
       }
       if (c === "@") {
         i++;
-        const name2 = readName();
+        const name2 = readAttributeName();
         skipWs();
         if (src[i] !== "=")
           return fail(`Expected '=' after @${name2}`);
@@ -528,7 +540,7 @@ function parseHtmlView(src, pos) {
         attrs.push({ name: name2, value: readQuoted(), event: true });
         continue;
       }
-      const name = readName();
+      const name = readAttributeName();
       skipWs();
       if (src[i] === "=") {
         i++;
@@ -546,7 +558,7 @@ function parseHtmlView(src, pos) {
       return fail(`Expected </${tag}>`);
     i += 2;
     skipWs();
-    const close = readName();
+    const close = readTagName();
     if (close !== tag)
       return fail(`Mismatched </${close}>, expected </${tag}>`);
     skipWs();
@@ -674,6 +686,9 @@ function parseHtmlView(src, pos) {
 }
 
 // ../../packages/compiler/src/codegen.ts
+function isComponentTag(tag) {
+  return /^[A-Z][A-Za-z0-9_$]*$/.test(tag);
+}
 function attrEscape(value) {
   return value.replace(/&/g, "&amp;").replace(/"/g, "&quot;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
 }
@@ -804,21 +819,30 @@ function bakeLoopAttr(raw) {
   return out + escLit(attrEscape(raw.slice(last)));
 }
 function renderLoopBody(node) {
-  if (node.type === "text")
+  if (node.type === "text") {
     return bakeLoopText(node.value);
-  if (node.type === "each")
+  }
+  if (node.type === "each") {
     return compileEachExpr(node);
-  if (node.type === "if")
+  }
+  if (node.type === "if") {
     return compileIfExpr(node);
-  const attrs = node.attrs.map((a) => {
-    const name = a.event ? eventAttribute(a.name) : a.name;
-    if (a.boolean)
+  }
+  const componentTag = isComponentTag(node.tag);
+  const attrs = node.attrs.filter((attr) => attr.name !== "data-component").map((attr) => {
+    const name = attr.event ? eventAttribute(attr.name) : attr.name;
+    if (attr.boolean) {
       return escLit(` ${name}`);
-    return escLit(` ${name}="`) + bakeLoopAttr(a.value) + escLit(`"`);
+    }
+    return escLit(` ${name}="`) + bakeLoopAttr(attr.value) + escLit(`"`);
   }).join("");
-  if (VOID_ELEMENTS.has(node.tag.toLowerCase()))
-    return escLit(`<${node.tag}`) + attrs + escLit(">");
   const inner = node.children.map(renderLoopBody).join("");
+  if (componentTag) {
+    return escLit(`<div data-component="${attrEscape(node.tag)}"`) + attrs + escLit(">") + inner + escLit("</div>");
+  }
+  if (VOID_ELEMENTS.has(node.tag.toLowerCase())) {
+    return escLit(`<${node.tag}`) + attrs + escLit(">");
+  }
   return escLit(`<${node.tag}`) + attrs + escLit(">") + inner + escLit(`</${node.tag}>`);
 }
 function compileEachExpr(node) {
@@ -862,6 +886,9 @@ function renderNode(node, ssrBindings, csrBindings, apiBindings, loops, reactive
     loops.push(node.type === "each" ? compileEachExpr(node) : compileIfExpr(node));
     return `\x00WRNEACH${loops.length - 1}\x00`;
   }
+  if (isComponentTag(node.tag)) {
+    return renderPageComponentInvocation(node, ssrBindings, csrBindings, apiBindings, loops, reactive);
+  }
   const apiName = attrValue(node.attrs, "api");
   const apiBinding = apiName ? apiBindings.get(apiName) : undefined;
   if (apiName && !apiBinding) {
@@ -888,6 +915,35 @@ function renderNode(node, ssrBindings, csrBindings, apiBindings, loops, reactive
   }) : node.children.map((child) => renderNode(child, ssrBindings, csrBindings, apiBindings, loops, reactive)).join("");
   return `<${node.tag}${renderAttrs(node.attrs, csrId, reactive)}>${inner}</${node.tag}>`;
 }
+function renderPageComponentInvocation(node, ssrBindings, csrBindings, apiBindings, loops, reactive) {
+  const attrs = node.attrs.filter((attr) => attr.name !== "data-component");
+  const inner = node.children.map((child) => renderNode(child, ssrBindings, csrBindings, apiBindings, loops, reactive)).join("");
+  return `<div data-component="${attrEscape(node.tag)}"${renderAttrs(attrs, undefined, reactive)}>${inner}</div>`;
+}
+function renderNestedComponentInvocation(node, ctx) {
+  let bindIndex = 0;
+  const attrs = node.attrs.filter((attr) => attr.name !== "data-component").map((attr) => {
+    if (attr.event) {
+      return ` ${eventAttribute(attr.name)}="${compileAttrValue(attr.value, ctx)}"`;
+    }
+    if (attr.boolean) {
+      return ` ${attr.name}`;
+    }
+    const rendered = ` ${attr.name}="` + `${compileAttrValue(attr.value, ctx)}"`;
+    if (!attr.value.includes("{") || !exprRefsState(attr.value, ctx.stateNames)) {
+      return rendered;
+    }
+    const marker = attrEscape(JSON.stringify([attr.name, attr.value]));
+    return rendered + ` data-wrn-bind-${bindIndex++}="${escLit(marker)}"`;
+  }).join("");
+  const loops = loopVarsOf(node);
+  const childCtx = loops.length > 0 ? {
+    ...ctx,
+    loopVars: new Set([...ctx.loopVars ?? [], ...loops])
+  } : ctx;
+  const inner = node.children.map((child) => renderComponentNode(child, childCtx)).join("");
+  return `<div data-component="${attrEscape(node.tag)}"${attrs}>${inner}</div>`;
+}
 function ssrMarker(bindings, binding) {
   const marker = `<!--wrnexus-ssr:${bindings.length}-->`;
   bindings.push({ marker, ...binding });
@@ -1000,8 +1056,9 @@ async function __wrnexusRenderSsrBindings(html: string, ctx: any): Promise<strin
 }`;
 }
 function generate(ast) {
-  if (ast.kind === "component")
+  if (ast.kind === "component" || ast.kind === "layout") {
     return generateComponent(ast);
+  }
   const out = [];
   const ssrBindings = [];
   const csrBindings = [];
@@ -1230,6 +1287,8 @@ function compileText(raw, ctx) {
       out += escLit(`{${expr}}`);
     } else if (exprRefsState(expr, ctx.stateNames)) {
       out += escLit(`<span data-text="${attrEscape(expr)}">`) + `\${__wireHtml(${ctx.resolveExpr(expr)})}` + escLit(`</span>`);
+    } else if (expr === "content") {
+      out += `\${__wireRaw(${ctx.resolveExpr(expr)})}`;
     } else {
       out += `\${__wireHtml(${ctx.resolveExpr(expr)})}`;
     }
@@ -1262,6 +1321,9 @@ function renderComponentNode(node, ctx) {
   if (node.type === "each" || node.type === "if") {
     throw new Error("Server `{#each}` / `{#if}` blocks are supported in pages, not components. Move them into a page (or use data-for / data-show on the client).");
   }
+  if (isComponentTag(node.tag)) {
+    return renderNestedComponentInvocation(node, ctx);
+  }
   let bindIndex = 0;
   const staticClasses = [];
   const conditionalClasses = [];
@@ -1309,10 +1371,18 @@ function renderComponentNode(node, ctx) {
 }
 function generateComponent(ast) {
   const out = [];
+  const effectiveProps = ast.kind === "layout" && !ast.props.some((prop) => prop.name === "content") ? [
+    {
+      name: "content",
+      default: '""'
+    },
+    ...ast.props
+  ] : ast.props;
   const stateNames = new Set(ast.states.map((s) => s.name));
   const nameRefs = new Map;
-  for (const p of ast.props)
+  for (const p of effectiveProps) {
     nameRefs.set(p.name, safeRef(p.name));
+  }
   for (const s of ast.states)
     nameRefs.set(s.name, safeRef(s.name));
   const resolveExpr = (expr) => {
@@ -1331,9 +1401,12 @@ ${styles.map(styleEscape).join(`
 `)}
 </style>`) : "";
   const needsScope = ast.states.length > 0 || viewHasEvents(ast.view);
-  const scopeKeys = [...ast.props.map((p) => p.name), ...ast.states.map((s) => s.name)];
+  const scopeKeys = [
+    ...effectiveProps.map((prop) => prop.name),
+    ...ast.states.map((state) => state.name)
+  ];
   const decls = [];
-  for (const prop of ast.props) {
+  for (const prop of effectiveProps) {
     decls.push(`  const ${nameRefs.get(prop.name)} = __coerce(__p[${JSON.stringify(prop.name)}], (${resolveExpr(prop.default)}));`);
   }
   for (const state of ast.states) {
@@ -1343,7 +1416,11 @@ ${styles.map(styleEscape).join(`
   const scopeLine = needsScope && scopeKeys.length > 0 ? `  const __scope = __wrnexusScopeDecl({ ${scopeKeys.map((k) => `${JSON.stringify(k)}: ${nameRefs.get(k)}`).join(", ")} });
 ` : needsScope ? `  const __scope = "";
 ` : "";
-  out.push(`export const __wrnexusComponent = ${JSON.stringify(ast.name)};`);
+  if (ast.kind === "layout") {
+    out.push(`export const __wrnexusLayout = ${JSON.stringify(ast.name)};`);
+  } else {
+    out.push(`export const __wrnexusComponent = ${JSON.stringify(ast.name)};`);
+  }
   out.push(`function __coerce(v: any, def: any): any {
   if (v === undefined || v === null) return def;
   if (typeof def === "number") return Number(v);

editors/vscode/src/completion.js

@@ -33,6 +33,20 @@ const BLOCK_COMPLETIONS = [
       "}",
     ].join("\n"),
   },
+  {
+    label: "layout",
+    detail: "WRN layout",
+    documentation: "Create a reusable WRN layout.",
+    snippet: [
+      "layout ${1:LayoutName} {",
+      "    view {",
+      "        <main>",
+      "            {content}",
+      "        </main>",
+      "    }",
+      "}",
+    ].join("\n"),
+  },
   {
     label: "seo",
     detail: "SEO metadata block",

editors/vscode/src/definition.js

@@ -0,0 +1,134 @@
+"use strict";
+
+const vscode = require("vscode");
+
+const COMPONENT_DECLARATION =
+  /^\s*(component|layout)\s+([A-Za-z_$][\w$]*)\s*\{/gm;
+
+function getTagAtPosition(document, position) {
+  const range = document.getWordRangeAtPosition(
+    position,
+    /[A-Za-z_$][\w$]*/,
+  );
+
+  if (!range) {
+    return null;
+  }
+
+  const name = document.getText(range);
+
+  if (!/^[A-Z][A-Za-z0-9_$]*$/.test(name)) {
+    return null;
+  }
+
+  const line = document.lineAt(position.line).text;
+  const offset = document.offsetAt(position);
+  const lineStart = document.offsetAt(
+    new vscode.Position(position.line, 0),
+  );
+
+  const characterOffset = offset - lineStart;
+  const before = line.slice(0, characterOffset);
+  const after = line.slice(characterOffset);
+
+  const insideTag =
+    before.lastIndexOf("<") > before.lastIndexOf(">") &&
+    after.includes(">");
+
+  if (!insideTag) {
+    return null;
+  }
+
+  return {
+    name,
+    range,
+  };
+}
+
+async function findDeclaration(name) {
+  const files = await vscode.workspace.findFiles(
+    "**/*.wrn",
+    "**/{node_modules,dist,.wrnexus,.git}/**",
+  );
+
+  const matches = [];
+
+  for (const uri of files) {
+    let document;
+
+    try {
+      document = await vscode.workspace.openTextDocument(uri);
+    } catch {
+      continue;
+    }
+
+    const source = document.getText();
+
+    COMPONENT_DECLARATION.lastIndex = 0;
+
+    let match;
+
+    while ((match = COMPONENT_DECLARATION.exec(source)) !== null) {
+      const declarationName = match[2];
+
+      if (declarationName !== name) {
+        continue;
+      }
+
+      const nameOffset =
+        match.index +
+        match[0].indexOf(declarationName);
+
+      const start = document.positionAt(nameOffset);
+      const end = document.positionAt(
+        nameOffset + declarationName.length,
+      );
+
+      matches.push(
+        new vscode.Location(
+          uri,
+          new vscode.Range(start, end),
+        ),
+      );
+    }
+  }
+
+  return matches;
+}
+
+async function provideDefinition(document, position) {
+  const tag = getTagAtPosition(document, position);
+
+  if (!tag) {
+    return null;
+  }
+
+  const matches = await findDeclaration(tag.name);
+
+  if (matches.length === 0) {
+    return null;
+  }
+
+  return matches.length === 1 ? matches[0] : matches;
+}
+
+function registerDefinitionProvider(context) {
+  const disposable = vscode.languages.registerDefinitionProvider(
+    {
+      language: "wrn",
+      scheme: "file",
+    },
+    {
+      provideDefinition,
+    },
+  );
+
+  context.subscriptions.push(disposable);
+}
+
+module.exports = {
+  findDeclaration,
+  getTagAtPosition,
+  provideDefinition,
+  registerDefinitionProvider,
+};

editors/vscode/src/diagnostics.js

@@ -0,0 +1,761 @@
+"use strict";
+
+const vscode = require("vscode");
+
+const COLLECTION_NAME = "wrnexus";
+const WRN_LANGUAGE_ID = "wrn";
+
+const TOP_LEVEL_PATTERN =
+  /^\s*(page|component|layout)\s+([A-Za-z_$][\w$]*)\s*\{/;
+
+const VALID_TOP_LEVEL_KINDS = new Set([
+  "page",
+  "component",
+  "layout",
+]);
+
+const VALID_MEMBERS = {
+  page: new Set([
+    "layout",
+    "state",
+    "view",
+    "seo",
+    "style",
+    "functions",
+    "api",
+    "ssr",
+    "client",
+    "realtime",
+  ]),
+
+  component: new Set([
+    "props",
+    "state",
+    "view",
+    "style",
+    "functions",
+  ]),
+
+  layout: new Set([
+    "props",
+    "state",
+    "view",
+    "style",
+    "functions",
+  ]),
+};
+
+function createDiagnostic(
+  document,
+  startOffset,
+  endOffset,
+  message,
+  severity = vscode.DiagnosticSeverity.Error,
+  code,
+) {
+  const diagnostic = new vscode.Diagnostic(
+    new vscode.Range(
+      document.positionAt(startOffset),
+      document.positionAt(endOffset),
+    ),
+    message,
+    severity,
+  );
+
+  diagnostic.source = "WRNexus";
+
+  if (code) {
+    diagnostic.code = code;
+  }
+
+  return diagnostic;
+}
+
+function lineDiagnostic(
+  document,
+  lineNumber,
+  message,
+  severity = vscode.DiagnosticSeverity.Error,
+  code,
+) {
+  const line = document.lineAt(lineNumber);
+
+  const diagnostic = new vscode.Diagnostic(
+    line.range,
+    message,
+    severity,
+  );
+
+  diagnostic.source = "WRNexus";
+
+  if (code) {
+    diagnostic.code = code;
+  }
+
+  return diagnostic;
+}
+
+function stripComments(source) {
+  return source.replace(/<!--[\s\S]*?-->/g, (comment) =>
+    comment.replace(/[^\n]/g, " "),
+  );
+}
+
+function findTopLevelDeclaration(document, source) {
+  const match = TOP_LEVEL_PATTERN.exec(source);
+
+  if (!match) {
+    const firstMeaningfulLine = source
+      .split(/\r?\n/)
+      .findIndex((line) => line.trim().length > 0);
+
+    return {
+      diagnostic: lineDiagnostic(
+        document,
+        Math.max(0, firstMeaningfulLine),
+        "A .wrn file must start with `page`, `component`, or `layout`.",
+        vscode.DiagnosticSeverity.Error,
+        "wrn-invalid-root",
+      ),
+    };
+  }
+
+  return {
+    kind: match[1],
+    name: match[2],
+    match,
+  };
+}
+
+function validateBalancedCharacters(document, source) {
+  const diagnostics = [];
+  const stack = [];
+
+  let quote = null;
+  let escaped = false;
+
+  const pairs = {
+    "}": "{",
+    "]": "[",
+    ")": "(",
+  };
+
+  for (let index = 0; index < source.length; index += 1) {
+    const character = source[index];
+
+    if (quote !== null) {
+      if (escaped) {
+        escaped = false;
+        continue;
+      }
+
+      if (character === "\\") {
+        escaped = true;
+        continue;
+      }
+
+      if (character === quote) {
+        quote = null;
+      }
+
+      continue;
+    }
+
+    if (character === '"' || character === "'") {
+      quote = character;
+      continue;
+    }
+
+    if (
+      source.startsWith("<!--", index)
+    ) {
+      const commentEnd = source.indexOf("-->", index + 4);
+
+      if (commentEnd === -1) {
+        diagnostics.push(
+          createDiagnostic(
+            document,
+            index,
+            Math.min(source.length, index + 4),
+            "Unclosed HTML comment.",
+            vscode.DiagnosticSeverity.Error,
+            "wrn-unclosed-comment",
+          ),
+        );
+
+        break;
+      }
+
+      index = commentEnd + 2;
+      continue;
+    }
+
+    if (
+      character === "{" ||
+      character === "[" ||
+      character === "("
+    ) {
+      stack.push({
+        character,
+        offset: index,
+      });
+
+      continue;
+    }
+
+    if (
+      character === "}" ||
+      character === "]" ||
+      character === ")"
+    ) {
+      const expectedOpening = pairs[character];
+      const opening = stack.pop();
+
+      if (!opening || opening.character !== expectedOpening) {
+        diagnostics.push(
+          createDiagnostic(
+            document,
+            index,
+            index + 1,
+            `Unexpected \`${character}\`.`,
+            vscode.DiagnosticSeverity.Error,
+            "wrn-unexpected-closing",
+          ),
+        );
+      }
+    }
+  }
+
+  for (const opening of stack) {
+    const expectedClosing =
+      opening.character === "{"
+        ? "}"
+        : opening.character === "["
+          ? "]"
+          : ")";
+
+    diagnostics.push(
+      createDiagnostic(
+        document,
+        opening.offset,
+        opening.offset + 1,
+        `Missing closing \`${expectedClosing}\`.`,
+        vscode.DiagnosticSeverity.Error,
+        "wrn-missing-closing",
+      ),
+    );
+  }
+
+  if (quote !== null) {
+    diagnostics.push(
+      createDiagnostic(
+        document,
+        Math.max(0, source.length - 1),
+        source.length,
+        `Unclosed ${quote === '"' ? "double" : "single"} quote.`,
+        vscode.DiagnosticSeverity.Error,
+        "wrn-unclosed-string",
+      ),
+    );
+  }
+
+  return diagnostics;
+}
+
+function validateHtmlTags(document, source) {
+  const diagnostics = [];
+  const stack = [];
+
+  const voidElements = new Set([
+    "area",
+    "base",
+    "br",
+    "col",
+    "embed",
+    "hr",
+    "img",
+    "input",
+    "link",
+    "meta",
+    "param",
+    "source",
+    "track",
+    "wbr",
+  ]);
+
+  const cleaned = stripComments(source);
+  const tagPattern =
+    /<\/?([A-Za-z][A-Za-z0-9_$:.-]*)(?:\s[\s\S]*?)?\/?>/g;
+
+  let match;
+
+  while ((match = tagPattern.exec(cleaned)) !== null) {
+    const completeTag = match[0];
+    const tagName = match[1];
+    const lowerTag = tagName.toLowerCase();
+
+    const isClosing = completeTag.startsWith("</");
+    const isSelfClosing = completeTag.endsWith("/>");
+    const isVoid = voidElements.has(lowerTag);
+
+    if (isClosing) {
+      const last = stack.pop();
+
+      if (!last) {
+        diagnostics.push(
+          createDiagnostic(
+            document,
+            match.index,
+            match.index + completeTag.length,
+            `Unexpected closing tag </${tagName}>.`,
+            vscode.DiagnosticSeverity.Error,
+            "wrn-unexpected-html-close",
+          ),
+        );
+
+        continue;
+      }
+
+      if (last.tagName !== tagName) {
+        diagnostics.push(
+          createDiagnostic(
+            document,
+            match.index,
+            match.index + completeTag.length,
+            `Mismatched closing tag </${tagName}>. Expected </${last.tagName}>.`,
+            vscode.DiagnosticSeverity.Error,
+            "wrn-mismatched-html-tag",
+          ),
+        );
+      }
+
+      continue;
+    }
+
+    if (!isSelfClosing && !isVoid) {
+      stack.push({
+        tagName,
+        offset: match.index,
+        length: completeTag.length,
+      });
+    }
+  }
+
+  for (const tag of stack) {
+    diagnostics.push(
+      createDiagnostic(
+        document,
+        tag.offset,
+        tag.offset + tag.length,
+        `Missing closing tag </${tag.tagName}>.`,
+        vscode.DiagnosticSeverity.Error,
+        "wrn-missing-html-close",
+      ),
+    );
+  }
+
+  return diagnostics;
+}
+
+function getRootBodyRange(source, rootMatch) {
+  const openingBrace =
+    rootMatch.index + rootMatch[0].lastIndexOf("{");
+
+  let depth = 0;
+  let quote = null;
+  let escaped = false;
+
+  for (
+    let index = openingBrace;
+    index < source.length;
+    index += 1
+  ) {
+    const character = source[index];
+
+    if (quote !== null) {
+      if (escaped) {
+        escaped = false;
+        continue;
+      }
+
+      if (character === "\\") {
+        escaped = true;
+        continue;
+      }
+
+      if (character === quote) {
+        quote = null;
+      }
+
+      continue;
+    }
+
+    if (character === '"' || character === "'") {
+      quote = character;
+      continue;
+    }
+
+    if (character === "{") {
+      depth += 1;
+      continue;
+    }
+
+    if (character === "}") {
+      depth -= 1;
+
+      if (depth === 0) {
+        return {
+          start: openingBrace + 1,
+          end: index,
+        };
+      }
+    }
+  }
+
+  return {
+    start: openingBrace + 1,
+    end: source.length,
+  };
+}
+
+function findRootMembers(source, bodyStart, bodyEnd) {
+  const members = [];
+  let index = bodyStart;
+  let depth = 0;
+  let quote = null;
+  let escaped = false;
+
+  while (index < bodyEnd) {
+    const character = source[index];
+
+    if (quote !== null) {
+      if (escaped) {
+        escaped = false;
+        index += 1;
+        continue;
+      }
+
+      if (character === "\\") {
+        escaped = true;
+        index += 1;
+        continue;
+      }
+
+      if (character === quote) {
+        quote = null;
+      }
+
+      index += 1;
+      continue;
+    }
+
+    if (character === '"' || character === "'") {
+      quote = character;
+      index += 1;
+      continue;
+    }
+
+    if (source.startsWith("<!--", index)) {
+      const end = source.indexOf("-->", index + 4);
+      index = end === -1 ? bodyEnd : end + 3;
+      continue;
+    }
+
+    if (character === "{") {
+      depth += 1;
+      index += 1;
+      continue;
+    }
+
+    if (character === "}") {
+      depth = Math.max(0, depth - 1);
+      index += 1;
+      continue;
+    }
+
+    if (
+      depth === 0 &&
+      /[A-Za-z_]/.test(character)
+    ) {
+      const start = index;
+      index += 1;
+
+      while (
+        index < bodyEnd &&
+        /[A-Za-z0-9_-]/.test(source[index])
+      ) {
+        index += 1;
+      }
+
+      const name = source.slice(start, index);
+
+      members.push({
+        name,
+        start,
+        end: index,
+      });
+
+      continue;
+    }
+
+    index += 1;
+  }
+
+  return members;
+}
+
+function validateRootMembers(
+  document,
+  source,
+  rootKind,
+  rootMatch,
+) {
+  const diagnostics = [];
+  const allowed = VALID_MEMBERS[rootKind];
+
+  if (!allowed) {
+    return diagnostics;
+  }
+
+  const bodyRange = getRootBodyRange(source, rootMatch);
+  const members = findRootMembers(
+    source,
+    bodyRange.start,
+    bodyRange.end,
+  );
+
+  for (const member of members) {
+    if (allowed.has(member.name)) {
+      continue;
+    }
+
+    diagnostics.push(
+      createDiagnostic(
+        document,
+        member.start,
+        member.end,
+        `Unknown ${rootKind} member \`${member.name}\`.`,
+        vscode.DiagnosticSeverity.Error,
+        "wrn-unknown-member",
+      ),
+    );
+  }
+
+  return diagnostics;
+}
+
+function validateRequiredView(
+  document,
+  source,
+  rootKind,
+  rootMatch,
+) {
+  const bodyRange = getRootBodyRange(source, rootMatch);
+  const body = source.slice(bodyRange.start, bodyRange.end);
+
+  if (/\bview\s*\{/.test(body)) {
+    return [];
+  }
+
+  return [
+    createDiagnostic(
+      document,
+      rootMatch.index,
+      rootMatch.index + rootMatch[0].length,
+      `The ${rootKind} \`${rootMatch[2]}\` does not contain a \`view { ... }\` block.`,
+      vscode.DiagnosticSeverity.Warning,
+      "wrn-missing-view",
+    ),
+  ];
+}
+
+function validateLayoutUsage(
+  document,
+  source,
+  rootKind,
+) {
+  const diagnostics = [];
+
+  if (
+    rootKind !== "page" &&
+    /^\s*layout\s*=/m.test(source)
+  ) {
+    const match = /^\s*layout\s*=/m.exec(source);
+
+    if (match) {
+      diagnostics.push(
+        createDiagnostic(
+          document,
+          match.index,
+          match.index + match[0].length,
+          "`layout = \"...\"` is only valid inside a page.",
+          vscode.DiagnosticSeverity.Error,
+          "wrn-invalid-layout-member",
+        ),
+      );
+    }
+  }
+
+  return diagnostics;
+}
+
+function validateDocument(document) {
+  if (document.languageId !== WRN_LANGUAGE_ID) {
+    return [];
+  }
+
+  const source = document.getText();
+
+  if (!source.trim()) {
+    return [];
+  }
+
+  const diagnostics = [];
+  const declaration = findTopLevelDeclaration(
+    document,
+    source,
+  );
+
+  if (declaration.diagnostic) {
+    diagnostics.push(declaration.diagnostic);
+    diagnostics.push(
+      ...validateBalancedCharacters(document, source),
+    );
+
+    return diagnostics;
+  }
+
+  if (!VALID_TOP_LEVEL_KINDS.has(declaration.kind)) {
+    diagnostics.push(
+      createDiagnostic(
+        document,
+        declaration.match.index,
+        declaration.match.index +
+          declaration.match[0].length,
+        `Unsupported WRN declaration \`${declaration.kind}\`.`,
+        vscode.DiagnosticSeverity.Error,
+        "wrn-invalid-kind",
+      ),
+    );
+
+    return diagnostics;
+  }
+
+  diagnostics.push(
+    ...validateBalancedCharacters(document, source),
+  );
+
+  diagnostics.push(
+    ...validateHtmlTags(document, source),
+  );
+
+  diagnostics.push(
+    ...validateRootMembers(
+      document,
+      source,
+      declaration.kind,
+      declaration.match,
+    ),
+  );
+
+  diagnostics.push(
+    ...validateRequiredView(
+      document,
+      source,
+      declaration.kind,
+      declaration.match,
+    ),
+  );
+
+  diagnostics.push(
+    ...validateLayoutUsage(
+      document,
+      source,
+      declaration.kind,
+    ),
+  );
+
+  return diagnostics;
+}
+
+function registerDiagnostics(context) {
+  const collection =
+    vscode.languages.createDiagnosticCollection(
+      COLLECTION_NAME,
+    );
+
+  const timers = new Map();
+
+  const update = (document) => {
+    if (document.languageId !== WRN_LANGUAGE_ID) {
+      return;
+    }
+
+    const previousTimer = timers.get(
+      document.uri.toString(),
+    );
+
+    if (previousTimer) {
+      clearTimeout(previousTimer);
+    }
+
+    const timer = setTimeout(() => {
+      timers.delete(document.uri.toString());
+
+      collection.set(
+        document.uri,
+        validateDocument(document),
+      );
+    }, 150);
+
+    timers.set(document.uri.toString(), timer);
+  };
+
+  for (const document of vscode.workspace.textDocuments) {
+    update(document);
+  }
+
+  context.subscriptions.push(
+    collection,
+
+    vscode.workspace.onDidOpenTextDocument(update),
+
+    vscode.workspace.onDidChangeTextDocument((event) => {
+      update(event.document);
+    }),
+
+    vscode.workspace.onDidSaveTextDocument(update),
+
+    vscode.workspace.onDidCloseTextDocument(
+      (document) => {
+        const key = document.uri.toString();
+        const timer = timers.get(key);
+
+        if (timer) {
+          clearTimeout(timer);
+          timers.delete(key);
+        }
+
+        collection.delete(document.uri);
+      },
+    ),
+
+    {
+      dispose() {
+        for (const timer of timers.values()) {
+          clearTimeout(timer);
+        }
+
+        timers.clear();
+      },
+    },
+  );
+}
+
+module.exports = {
+  registerDiagnostics,
+  validateBalancedCharacters,
+  validateDocument,
+  validateHtmlTags,
+  validateRootMembers,
+};

editors/vscode/src/extension.js

@@ -4,6 +4,8 @@
 const vscode = require("vscode");
 const { formatWrn } = require("./formatter");
 const { registerCompletionProvider } = require("./completion");
+const { registerDefinitionProvider } = require("./definition");
+const { registerDiagnostics } = require("./diagnostics");
 
 // The .wrn compiler, bundled to CJS by `bun run build:compiler`. Loaded
 // defensively so the rest of the extension (highlighting, snippets, completion)
@@ -68,7 +70,9 @@ const EVENTS = [
  * @param {vscode.ExtensionContext} context
  */
 function activate(context) {
+  registerDiagnostics(context);
   registerCompletionProvider(context);
+  registerDefinitionProvider(context);
 
   const diagnostics = vscode.languages.createDiagnosticCollection("wrn");
   context.subscriptions.push(diagnostics);

editors/vscode/syntaxes/wrn.tmLanguage.json

@@ -14,7 +14,7 @@
     },
 
     "declaration": {
-      "match": "\\b(page|component)\\b\\s+([A-Za-z_][A-Za-z0-9_]*)?",
+      "match": "\\b(page|component|layout)\\b\\s+([A-Za-z_][A-Za-z0-9_]*)?",
       "captures": {
         "1": { "name": "storage.type.wrn keyword.control.wrn" },
         "2": { "name": "entity.name.type.wrn" }