feat: support toml (uses prettier-plugin-toml)

README.md

@@ -173,6 +173,14 @@ Formatting embedded SQL code requires [`prettier-plugin-sql`](https://github.com
 
 Note that `prettier-plugin-sql` supports many different SQL dialects and they are specified by the [`language` or `database` option](https://github.com/un-ts/prettier/tree/master/packages/sql#parser-options). To map a subset of identifiers to another dialect, please use [`embeddedOverrides`](#embeddedoverrides).
 
+#### TOML
+
+|          Option           |                  Default                  | Description                                                                                        |
+| :-----------------------: | :---------------------------------------: | -------------------------------------------------------------------------------------------------- |
+| `embeddedTomlIdentifiers` | [`[...]`](./src/embedded/toml/options.ts) | Tag or comment identifiers that make their subsequent template literals be identified as TOML code |
+
+Formatting embedded TOML code requires [`prettier-plugin-toml`](https://github.com/un-ts/prettier/tree/master/packages/toml#readme) to be loaded as well. And options supported by `prettier-plugin-toml` can therefore be used to further control the formatting behavior.
+
 #### TS
 
 |         Option          |                    Default                     | Description                                                                                              |

package.json

@@ -63,6 +63,9 @@
   "devDependencies": {
     "@commitlint/cli": "^18.4.3",
     "@commitlint/config-conventional": "^18.4.3",
+    "@prettier/plugin-php": ">=0.20.1 <1",
+    "@prettier/plugin-ruby": "^4.0.0",
+    "@prettier/plugin-xml": "^3.1.0",
     "@semantic-release/git": "^10.0.1",
     "@types/estree": "^1.0.5",
     "@types/node": "^20.10.0",
@@ -71,26 +74,24 @@
     "@vitest/browser": "^0.34.6",
     "@vitest/coverage-istanbul": "^0.34.6",
     "@vitest/ui": "^0.34.6",
+    "@xml-tools/parser": "^1.0.11",
+    "chevrotain": "7.1.1",
     "code-tag": "^1.1.0",
     "esbuild": "^0.19.8",
     "eslint": "^8.54.0",
     "fast-glob": "^3.3.2",
     "npm-check-updates": "^16.14.11",
     "playwright": "^1.40.0",
+    "prettier": "^3.0.0",
+    "prettier-plugin-glsl": ">=0.1.2 <1",
     "prettier-plugin-organize-imports": "^3.2.4",
+    "prettier-plugin-sql": ">=0.15.0 <1",
+    "prettier-plugin-toml": "^2.0.1",
     "semantic-release": "^22.0.8",
     "tsx": "^4.5.0",
     "typescript": "^5.3.2",
     "vite": "^5.0.2",
-    "vitest": "^0.34.6",
-    "@prettier/plugin-php": ">=0.20.1 <1",
-    "@prettier/plugin-ruby": "^4.0.0",
-    "@prettier/plugin-xml": "^3.1.0",
-    "@xml-tools/parser": "^1.0.11",
-    "chevrotain": "7.1.1",
-    "prettier": "^3.0.0",
-    "prettier-plugin-glsl": ">=0.1.2 <1",
-    "prettier-plugin-sql": ">=0.15.0 <1"
+    "vitest": "^0.34.6"
   },
   "dependencies": {
     "micro-memoize": "^4.1.2",

src/embedded/toml/embedded-language.ts

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

src/embedded/toml/embedder.ts

@@ -0,0 +1,110 @@
+import type { Options } from "prettier";
+import { builders, utils } from "prettier/doc";
+import type { Embedder } from "../../types.js";
+import {
+  preparePlaceholder,
+  printTemplateExpressions,
+  throwIfPluginIsNotFound,
+} from "../utils.js";
+import { embeddedLanguage } from "./embedded-language.js";
+
+const { line, group, indent, softline, hardline } = builders;
+const { mapDoc } = utils;
+
+export const embedder: Embedder<Options> = async (
+  textToDoc,
+  print,
+  path,
+  options,
+  { identifier, embeddedOverrideOptions },
+) => {
+  throwIfPluginIsNotFound("prettier-plugin-toml", 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: "toml",
+  });
+
+  const contentDoc = mapDoc(doc, (doc) => {
+    if (typeof doc !== "string") {
+      return doc;
+    }
+    const parts = [];
+    const components = doc.split(placeholderRegex);
+    for (let i = 0; i < components.length; i++) {
+      let component = components[i];
+      if (i % 2 == 0) {
+        if (!component) {
+          continue;
+        }
+        component = component.replaceAll(/([\\`]|\${)/g, "\\$1");
+        component
+          .split(/(\n)/)
+          .forEach((c) => (c === "\n" ? parts.push(hardline) : parts.push(c)));
+      } else {
+        const placeholderIndex = Number(component);
+        parts.push(expressionDocs[placeholderIndex]);
+      }
+    }
+    return parts;
+  });
+
+  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/toml/index.ts

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

src/embedded/toml/options.ts

@@ -0,0 +1,46 @@
+import type { CoreCategoryType, SupportOptions } from "prettier";
+import type { PrettierTaploOptions } from "prettier-plugin-toml";
+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#L6890
+ */
+const DEFAULT_IDENTIFIERS = ["toml"] as const;
+type Identifiers = AutocompleteStringList<typeof DEFAULT_IDENTIFIERS>;
+type DefaultIdentifiersHolder = StringListToInterfaceKey<
+  typeof DEFAULT_IDENTIFIERS
+>;
+
+const embeddedLanguageIdentifiers = makeIdentifiersOptionName(embeddedLanguage);
+
+export interface PrettierPluginDepsOptions extends PrettierTaploOptions {}
+
+export const options = {
+  [embeddedLanguageIdentifiers]: {
+    category: "Global",
+    type: "string",
+    array: true,
+    default: [{ value: [...DEFAULT_IDENTIFIERS] }],
+    description:
+      'Specify embedded TOML language identifiers. This requires "prettier-plugin-toml".',
+  },
+} 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 {}
+}