feat: support latex

uses `prettier-plugin-latex`

README.md

@@ -146,6 +146,14 @@ Formatting embedded HTML code doesn't require other plugins and uses the parsers
 
 Formatting embedded INI code requires [`prettier-plugin-ini`](https://github.com/kddnewton/prettier-plugin-ini) to be loaded as well. And [options](https://github.com/kddnewton/prettier-plugin-ini#configuration) supported by `prettier-plugin-ini` can therefore be used to further control the formatting behavior.
 
+#### LaTeX
+
+|           Option           |                  Default                   | Description                                                                                         |
+| :------------------------: | :----------------------------------------: | --------------------------------------------------------------------------------------------------- |
+| `embeddedLatexIdentifiers` | [`[...]`](./src/embedded/latex/options.ts) | Tag or comment identifiers that make their subsequent template literals be identified as LaTeX code |
+
+Formatting embedded LaTeX code requires [`prettier-plugin-latex`](https://github.com/siefkenj/prettier-plugin-latex) to be loaded as well.
+
 #### Markdown
 
 |            Option             |                    Default                    | Description                                                                                            |

package.json

@@ -85,6 +85,7 @@
     "prettier": "^3.0.0",
     "prettier-plugin-glsl": ">=0.1.2 <1",
     "prettier-plugin-ini": "^1.1.0",
+    "prettier-plugin-latex": "^2.0.1",
     "prettier-plugin-organize-imports": "^3.2.4",
     "prettier-plugin-sql": ">=0.15.0 <1",
     "prettier-plugin-toml": "^2.0.1",

src/embedded/latex/embedded-language.ts

@@ -0,0 +1,7 @@
+export const embeddedLanguage = "embeddedLatex";
+
+declare module "../types.js" {
+  interface EmbeddedLanguagesHolder {
+    [embeddedLanguage]: void;
+  }
+}

src/embedded/latex/embedder.ts

@@ -0,0 +1,88 @@
+import type { Options } from "prettier";
+import { builders } from "prettier/doc";
+import type { Embedder } from "../../types.js";
+import {
+  preparePlaceholder,
+  printTemplateExpressions,
+  simpleRehydrateDoc,
+  throwIfPluginIsNotFound,
+} from "../utils.js";
+import { embeddedLanguage } from "./embedded-language.js";
+
+const { line, group, indent, softline } = builders;
+
+export const embedder: Embedder<Options> = async (
+  textToDoc,
+  print,
+  path,
+  options,
+  { identifier, embeddedOverrideOptions },
+) => {
+  throwIfPluginIsNotFound("prettier-plugin-latex", options, identifier);
+
+  options = {
+    ...options,
+    ...embeddedOverrideOptions,
+  };
+
+  const { node } = path;
+
+  const { createPlaceholder, placeholderRegex } = preparePlaceholder();
+
+  const text = node.quasis
+    .map((quasi, index, { length }) =>
+      index === length - 1
+        ? quasi.value.cooked
+        : quasi.value.cooked + createPlaceholder(index),
+    )
+    .join("");
+
+  const leadingWhitespaces = text.match(/^\s+/)?.[0] ?? "";
+  const trailingWhitespaces = text.match(/\s+$/)?.[0] ?? "";
+
+  const trimmedText = text.slice(
+    leadingWhitespaces.length,
+    -trailingWhitespaces.length || undefined,
+  );
+
+  const expressionDocs = printTemplateExpressions(path, print);
+
+  const doc = await textToDoc(trimmedText, {
+    ...options,
+    parser: "latex-parser",
+  });
+
+  const contentDoc = simpleRehydrateDoc(doc, placeholderRegex, expressionDocs);
+
+  if (options.preserveEmbeddedExteriorWhitespaces?.includes(identifier)) {
+    // TODO: should we label the doc with { hug: false } ?
+    // https://github.com/prettier/prettier/blob/5cfb76ee50cf286cab267cf3cb7a26e749c995f7/src/language-js/embed/html.js#L88
+    return group([
+      "`",
+      leadingWhitespaces,
+      options.noEmbeddedMultiLineIndentation?.includes(identifier)
+        ? [group(contentDoc)]
+        : indent([group(contentDoc)]),
+      trailingWhitespaces,
+      "`",
+    ]);
+  }
+
+  const leadingLineBreak = leadingWhitespaces.length ? line : softline;
+  const trailingLineBreak = trailingWhitespaces.length ? line : softline;
+
+  return group([
+    "`",
+    options.noEmbeddedMultiLineIndentation?.includes(identifier)
+      ? [leadingLineBreak, group(contentDoc)]
+      : indent([leadingLineBreak, group(contentDoc)]),
+    trailingLineBreak,
+    "`",
+  ]);
+};
+
+declare module "../types.js" {
+  interface EmbeddedEmbedders {
+    [embeddedLanguage]: typeof embedder;
+  }
+}

src/embedded/latex/index.ts

@@ -0,0 +1,3 @@
+export * from "./embedded-language.js";
+export * from "./embedder.js";
+export * from "./options.js";

src/embedded/latex/options.ts

@@ -0,0 +1,54 @@
+import type { CoreCategoryType, SupportOptions } from "prettier";
+import {
+  makeIdentifiersOptionName,
+  type AutocompleteStringList,
+  type StringListToInterfaceKey,
+} from "../utils.js";
+import { embeddedLanguage } from "./embedded-language.js";
+
+/** References:
+ * - https://github.com/github-linguist/linguist/blob/7ca3799b8b5f1acde1dd7a8dfb7ae849d3dfb4cd/lib/linguist/languages.yml#L6994
+ */
+const DEFAULT_IDENTIFIERS = [
+  "latex",
+  "tex",
+  "aux",
+  "cls",
+  "bbl",
+  "bib",
+  "toc",
+  "sty",
+] as const;
+type Identifiers = AutocompleteStringList<typeof DEFAULT_IDENTIFIERS>;
+type DefaultIdentifiersHolder = StringListToInterfaceKey<
+  typeof DEFAULT_IDENTIFIERS
+>;
+
+const embeddedLanguageIdentifiers = makeIdentifiersOptionName(embeddedLanguage);
+
+export interface PrettierPluginDepsOptions {}
+
+export const options = {
+  [embeddedLanguageIdentifiers]: {
+    category: "Global",
+    type: "string",
+    array: true,
+    default: [{ value: [...DEFAULT_IDENTIFIERS] }],
+    description:
+      'Specify embedded LaTeX language identifiers. This requires "prettier-plugin-latex".',
+  },
+} satisfies SupportOptions & Record<string, { category: CoreCategoryType }>;
+
+type Options = typeof options;
+
+declare module "../types.js" {
+  interface EmbeddedOptions extends Options {}
+  interface EmbeddedDefaultIdentifiersHolder extends DefaultIdentifiersHolder {}
+  interface PrettierPluginEmbedOptions {
+    [embeddedLanguageIdentifiers]?: Identifiers;
+  }
+}
+
+declare module "prettier" {
+  export interface Options extends PrettierPluginDepsOptions {}
+}