feat: implement hover provider for tag names

.changeset/tender-peaches-yell.md

@@ -0,0 +1,6 @@
+---
+"marko-vscode": patch
+"@marko/language-server": patch
+---
+
+Implement hover provider for tag names.

server/src/service/marko/hover/OpenTagName.ts

@@ -0,0 +1,30 @@
+import type { Node } from "../../../utils/parser";
+import { getDocFile } from "../../../utils/doc-file";
+import type { HoverMeta, HoverResult } from ".";
+import getTagNameCompletion from "../util/get-tag-name-completion";
+import { START_OF_FILE } from "../../../utils/utils";
+import type { MarkupContent } from "vscode-languageserver";
+
+export function OpenTagName({
+  document,
+  lookup,
+  parsed,
+  node,
+}: HoverMeta<Node.OpenTagName>): HoverResult {
+  const importer = getDocFile(document);
+  const tag = node.parent;
+  const range = parsed.locationAt(node);
+  const tagDef = tag.nameText && lookup.getTag(tag.nameText);
+
+  if (tagDef) {
+    const completion = getTagNameCompletion({
+      tag: tagDef,
+      range: START_OF_FILE,
+      importer,
+    });
+    return {
+      range,
+      contents: completion.documentation as MarkupContent,
+    };
+  }
+}

server/src/service/marko/hover/index.ts

@@ -0,0 +1,36 @@
+import type { TextDocument } from "vscode-languageserver-textdocument";
+import type { HoverParams, Hover } from "vscode-languageserver";
+import { getCompilerInfo, parse } from "../../../utils/compiler";
+import type { Plugin, Result } from "../../types";
+import { NodeType } from "../../../utils/parser";
+import { OpenTagName } from "./OpenTagName";
+
+export type HoverResult = Result<Hover>;
+export interface HoverMeta<N = unknown>
+  extends ReturnType<typeof getCompilerInfo> {
+  document: TextDocument;
+  params: HoverParams;
+  parsed: ReturnType<typeof parse>;
+  offset: number;
+  code: string;
+  node: N;
+}
+
+const handlers: Record<string, (data: HoverMeta<any>) => HoverResult> = {
+  OpenTagName,
+};
+
+export const doHover: Plugin["doHover"] = async (doc, params) => {
+  const parsed = parse(doc);
+  const offset = doc.offsetAt(params.position);
+  const node = parsed.nodeAt(offset);
+  return await handlers[NodeType[node.type]]?.({
+    document: doc,
+    params,
+    parsed,
+    offset,
+    node,
+    code: doc.getText(),
+    ...getCompilerInfo(doc),
+  });
+};

server/src/service/marko/index.ts

@@ -1,6 +1,7 @@
 import type { Plugin } from "../types";
 import { doComplete } from "./complete";
 import { doValidate } from "./validate";
+import { doHover } from "./hover";
 import { findDefinition } from "./definition";
 import { findDocumentLinks } from "./document-links";
 import { findDocumentSymbols } from "./document-symbols";
@@ -9,6 +10,7 @@ import { format } from "./format";
 export default {
   doComplete,
   doValidate,
+  doHover,
   findDefinition,
   findDocumentLinks,
   findDocumentSymbols,

server/src/service/marko/util/get-tag-name-completion.ts

@@ -32,16 +32,16 @@ export default function getTagNameCompletion({
   );
 
   const nodeModuleName = nodeModuleMatch && nodeModuleMatch[1];
-  const isCoreTag = nodeModuleName === "marko";
-
+  const isCoreTag =
+    /^@?marko[/-]/.test(tag.taglibId) || nodeModuleName === "marko";
   const documentation = {
     kind: MarkupKind.Markdown,
     value: tag.html
-      ? `Built in [<${tag.name}>](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/${tag.name}) HTML tag.`
+      ? `Built in [&lt;${tag.name}&gt;](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/${tag.name}) HTML tag.`
+      : isCoreTag
+      ? `Core Marko &lt;${tag.name}&gt; tag.`
       : nodeModuleName
-      ? isCoreTag
-        ? `Core Marko [<${tag.name}>](${fileURIForTag}) tag.`
-        : `Custom Marko tag discovered from the ["${nodeModuleName}"](${fileURIForTag}) npm package.`
+      ? `Custom Marko tag discovered from the ["${nodeModuleName}"](${fileURIForTag}) npm package.`
       : `Custom Marko tag discovered from:\n\n[${
           importer ? path.relative(importer, fileForTag) : fileForTag
         }](${fileURIForTag})`,