feat: customize rendering of @param, @result, and @typeParam tags (#764)

Closes partially #669

### Summary of Changes

Write tag in bold and the declaration name in italics for rendered
`@param`, `@result` and `@typeParam` tags.

Author: lars-reimann

packages/safe-ds-lang/src/helpers/stringUtils.ts

@@ -1,3 +1,13 @@
+/**
+ * Normalizes line breaks to `\n`.
+ *
+ * @param text The text to normalize.
+ * @return The normalized text.
+ */
+export const normalizeLineBreaks = (text: string | undefined): string => {
+    return text?.replace(/\r\n?/gu, '\n') ?? '';
+};
+
 /**
  * Based on the given count, returns the singular or plural form of the given word.
  */

packages/safe-ds-lang/src/language/documentation/safe-ds-documentation-provider.ts

@@ -5,6 +5,7 @@ import {
     JSDocComment,
     JSDocDocumentationProvider,
     JSDocRenderOptions,
+    type JSDocTag,
     parseJSDoc,
 } from 'langium';
 import {
@@ -17,6 +18,10 @@ import {
     SdsTypeParameter,
 } from '../generated/ast.js';
 
+const PARAM_TAG = 'param';
+const RESULT_TAG = 'result';
+const TYPE_PARAM_TAG = 'typeParam';
+
 export class SafeDsDocumentationProvider extends JSDocDocumentationProvider {
     override getDocumentation(node: AstNode): string | undefined {
         if (isSdsParameter(node) || isSdsResult(node) || isSdsTypeParameter(node)) {
@@ -39,6 +44,16 @@ export class SafeDsDocumentationProvider extends JSDocDocumentationProvider {
         }
     }
 
+    protected override documentationTagRenderer(node: AstNode, tag: JSDocTag): string | undefined {
+        if (tag.name === PARAM_TAG || tag.name === RESULT_TAG || tag.name === TYPE_PARAM_TAG) {
+            const contentMd = tag.content.toMarkdown();
+            const [paramName, description] = contentMd.split(/\s(.*)/su);
+            return `**@${tag.name}** *${paramName}* — ${(description ?? '').trim()}`;
+        } else {
+            return super.documentationTagRenderer(node, tag);
+        }
+    }
+
     private getJSDocComment(node: AstNode): JSDocComment | undefined {
         const comment = this.commentProvider.getComment(node);
         if (comment && isJSDoc(comment)) {
@@ -70,11 +85,11 @@ export class SafeDsDocumentationProvider extends JSDocDocumentationProvider {
 
     private getTagName(node: SdsParameter | SdsResult | SdsTypeParameter): string {
         if (isSdsParameter(node)) {
-            return 'param';
+            return PARAM_TAG;
         } else if (isSdsResult(node)) {
-            return 'result';
+            return RESULT_TAG;
         } else {
-            return 'typeParam';
+            return TYPE_PARAM_TAG;
         }
     }
 
@@ -83,6 +98,10 @@ export class SafeDsDocumentationProvider extends JSDocDocumentationProvider {
             renderLink: (link, display) => {
                 return this.documentationLinkRenderer(node, link, display);
             },
+            tag: 'bold',
+            renderTag: (tag: JSDocTag) => {
+                return this.documentationTagRenderer(node, tag);
+            },
         };
     }
 }

packages/safe-ds-lang/tests/helpers/stringUtils.test.ts

@@ -1,5 +1,32 @@
 import { describe, expect, it } from 'vitest';
-import { pluralize } from '../../src/helpers/stringUtils.js';
+import { normalizeLineBreaks, pluralize } from '../../src/helpers/stringUtils.js';
+
+describe('normalizeLineBreaks', () => {
+    it.each([
+        {
+            text: undefined,
+            expected: '',
+        },
+        {
+            text: '',
+            expected: '',
+        },
+        {
+            text: 'foo\nbar',
+            expected: 'foo\nbar',
+        },
+        {
+            text: 'foo\rbar',
+            expected: 'foo\nbar',
+        },
+        {
+            text: 'foo\r\nbar',
+            expected: 'foo\nbar',
+        },
+    ])(`should normalize line breaks (%#)`, ({ text, expected }) => {
+        expect(normalizeLineBreaks(text)).toBe(expected);
+    });
+});
 
 describe('pluralize', () => {
     it.each([

packages/safe-ds-lang/tests/language/documentation/safe-ds-documentation-provider.test.ts

@@ -1,15 +1,16 @@
-import { afterEach, describe, expect, it } from 'vitest';
-import { createSafeDsServices } from '../../../src/language/safe-ds-module.js';
-import { AstNode, EmptyFileSystem } from 'langium';
+import { AstNode, EmptyFileSystem, expandToString } from 'langium';
 import { clearDocuments } from 'langium/test';
-import { getNodeOfType } from '../../helpers/nodeFinder.js';
+import { afterEach, describe, expect, it } from 'vitest';
+import { normalizeLineBreaks } from '../../../src/helpers/stringUtils.js';
 import {
     isSdsAnnotation,
     isSdsFunction,
     isSdsParameter,
     isSdsResult,
     isSdsTypeParameter,
 } from '../../../src/language/generated/ast.js';
+import { createSafeDsServices } from '../../../src/language/index.js';
+import { getNodeOfType } from '../../helpers/nodeFinder.js';
 
 const services = createSafeDsServices(EmptyFileSystem).SafeDs;
 const documentationProvider = services.documentation.DocumentationProvider;
@@ -166,11 +167,39 @@ describe('SafeDsDocumentationProvider', () => {
             predicate: isSdsTypeParameter,
             expectedDocumentation: undefined,
         },
+        {
+            testName: 'custom tag rendering',
+            code: `
+                /**
+                 * ${testDocumentation}
+                 *
+                 * @param param ${testDocumentation}
+                 * @result result ${testDocumentation}
+                 * @typeParam T ${testDocumentation}
+                 * @since 1.0.0
+                 */
+                fun myFunction<T>(param: String) -> result: String
+            `,
+            predicate: isSdsFunction,
+            expectedDocumentation: expandToString`
+                Lorem ipsum.
+
+                **@param** *param* — Lorem ipsum.
+
+                **@result** *result* — Lorem ipsum.
+
+                **@typeParam** *T* — Lorem ipsum.
+
+                **@since** — 1.0.0
+            `,
+        },
     ];
 
     it.each(testCases)('$testName', async ({ code, predicate, expectedDocumentation }) => {
         const node = await getNodeOfType(services, code, predicate);
-        expect(documentationProvider.getDocumentation(node)).toStrictEqual(expectedDocumentation);
+        const normalizedActual = normalizeLineBreaks(documentationProvider.getDocumentation(node));
+        const normalizedExpected = normalizeLineBreaks(expectedDocumentation);
+        expect(normalizedActual).toStrictEqual(normalizedExpected);
     });
 
     it('should resolve links', async () => {

packages/safe-ds-lang/tests/language/lsp/formatting/creator.ts

@@ -1,6 +1,7 @@
 import fs from 'fs';
 import { EmptyFileSystem, URI } from 'langium';
 import { Diagnostic } from 'vscode-languageserver';
+import { normalizeLineBreaks } from '../../../../src/helpers/stringUtils.js';
 import { createSafeDsServices } from '../../../../src/language/index.js';
 import { getSyntaxErrors } from '../../../helpers/diagnostics.js';
 import { TestDescription, TestDescriptionError } from '../../../helpers/testDescription.js';
@@ -64,16 +65,6 @@ const invalidTest = (error: TestDescriptionError): FormattingTest => {
     };
 };
 
-/**
- * Normalizes line breaks to `\n`.
- *
- * @param code The code to normalize.
- * @return The normalized code.
- */
-const normalizeLineBreaks = (code: string): string => {
-    return code.replace(/\r\n?/gu, '\n');
-};
-
 /**
  * A description of a formatting test.
  */