moved generator API to a dedicated package export, solves #1285

examples/domainmodel/src/benchmark/generate.ts

@@ -4,7 +4,8 @@
  * terms of the MIT License, which is available in the project root.
  ******************************************************************************/
 
-import { expandToString, URI } from 'langium';
+import { URI } from 'langium';
+import { expandToString } from 'langium/generate';
 import type { DomainModelServices } from '../language-server/domain-model-module.js';
 
 export function generateWorkspace(services: DomainModelServices, width: number, size: number): void {

examples/domainmodel/src/cli/generator.ts

@@ -4,18 +4,17 @@
  * terms of the MIT License, which is available in the project root.
  ******************************************************************************/
 
-import type { IndentNode } from 'langium';
-import type { AbstractElement, Domainmodel, Entity, Feature, Type } from '../language-server/generated/ast.js';
-import * as fs from 'node:fs';
-import * as path from 'node:path';
 import chalk from 'chalk';
+import { type Generated, expandToNode, joinToNode, toString } from 'langium/generate';
+import { NodeFileSystem } from 'langium/node';
 import _ from 'lodash';
-import { CompositeGeneratorNode, NL, toString } from 'langium';
-import { isEntity, isPackageDeclaration } from '../language-server/generated/ast.js';
-import { extractAstNode, extractDestinationAndName, setRootFolder } from './cli-util.js';
+import * as fs from 'node:fs';
+import * as path from 'node:path';
 import { createDomainModelServices } from '../language-server/domain-model-module.js';
+import type { AbstractElement, Domainmodel, Entity, Feature, Type } from '../language-server/generated/ast.js';
+import { isEntity, isPackageDeclaration } from '../language-server/generated/ast.js';
 import { DomainModelLanguageMetaData } from '../language-server/generated/module.js';
-import { NodeFileSystem } from 'langium/node';
+import { extractAstNode, extractDestinationAndName, setRootFolder } from './cli-util.js';
 
 export const generateAction = async (fileName: string, opts: GenerateOptions): Promise<void> => {
     try {
@@ -57,9 +56,11 @@ function generateAbstractElements(destination: string, elements: Array<AbstractE
             if (isPackageDeclaration(elem)) {
                 generateAbstractElementsInternal(elem.elements, path.join(filePath, elem.name.replace(/\./g, '/')));
             } else if (isEntity(elem)) {
-                const fileNode = new CompositeGeneratorNode();
-                fileNode.append(`package ${packagePath};`, NL, NL);
-                generateEntity(elem, fileNode);
+                const fileNode = expandToNode`
+                    package ${packagePath};
+
+                    ${generateEntity(elem)}
+                `;
                 fs.writeFileSync(path.join(fullPath, `${elem.name}.java`), toString(fileNode));
             }
         }
@@ -69,40 +70,32 @@ function generateAbstractElements(destination: string, elements: Array<AbstractE
     return generateAbstractElementsInternal(elements, filePath);
 }
 
-function generateEntity(entity: Entity, fileNode: CompositeGeneratorNode): void {
+function generateEntity(entity: Entity): Generated {
     const maybeExtends = entity.superType ? ` extends ${entity.superType.$refText}` : '';
-    fileNode.append(`class ${entity.name}${maybeExtends} {`, NL);
-    fileNode.indent(classBody => {
-        const featureData = entity.features.map(f => generateFeature(f, classBody));
-        featureData.forEach(([generateField, , ]) => generateField());
-        featureData.forEach(([, generateSetter, generateGetter]) => { generateSetter(); generateGetter(); } );
-    });
-    fileNode.append('}', NL);
+    const featureData = entity.features.map(generateFeature);
+    return expandToNode`
+        class ${entity.name}${maybeExtends} {
+            ${joinToNode(featureData, ([field]) => field, { appendNewLineIfNotEmpty: true})}
+            ${joinToNode(featureData, ([, setterAndGetter]) => setterAndGetter, { appendNewLineIfNotEmpty: true} )}
+        }
+    `.appendNewLine();
 }
 
-function generateFeature(feature: Feature, classBody: IndentNode): [() => void, () => void, () => void] {
+function generateFeature(feature: Feature): [ string, Generated ] {
     const name = feature.name;
     const type = feature.type.$refText + (feature.many ? '[]' : '');
 
     return [
-        () => { // generate the field
-            classBody.append(`private ${type} ${name};`, NL);
-        },
-        () => { // generate the setter
-            classBody.append(NL);
-            classBody.append(`public void set${_.upperFirst(name)}(${type} ${name}) {`, NL);
-            classBody.indent(methodBody => {
-                methodBody.append(`this.${name} = ${name};`, NL);
-            });
-            classBody.append('}', NL);
-        },
-        () => { // generate the getter
-            classBody.append(NL);
-            classBody.append(`public ${type} get${_.upperFirst(name)}() {`, NL);
-            classBody.indent(methodBody => {
-                methodBody.append(`return ${name};`, NL);
-            });
-            classBody.append('}', NL);
-        }
+        `private ${type} ${name};`,
+        expandToNode`
+
+            public void set${_.upperFirst(name)}(${type} ${name}) {
+                this.${name} = ${name};
+            }
+
+            public ${type} get${_.upperFirst(name)}() {
+                return ${name};
+            }
+        `
     ];
 }

examples/requirements/src/cli/generator.ts

@@ -4,10 +4,10 @@
  * terms of the MIT License, which is available in the project root.
  ******************************************************************************/
 
-import type { RequirementModel, TestModel } from '../language-server/generated/ast.js';
+import { expandToNode, joinToNode, toString } from 'langium/generate';
 import * as fs from 'node:fs';
 import * as path from 'node:path';
-import { CompositeGeneratorNode, NL, toString } from 'langium';
+import type { RequirementModel, TestModel } from '../language-server/generated/ast.js';
 import { extractDestinationAndName } from './cli-util.js';
 
 /**
@@ -17,26 +17,34 @@ import { extractDestinationAndName } from './cli-util.js';
  * @returns the content of the HTML file.
  */
 export function generateSummaryFileHTMLContent(model: RequirementModel, testModels: TestModel[]): string {
-    const fileNode = new CompositeGeneratorNode();
-    fileNode.append('<html>', NL);
-    fileNode.append('<body>', NL);
-    fileNode.append('<h1>Requirement coverage (demo generator)</h1>', NL);
-    fileNode.append(`<div>Source: ${model.$document?.uri.fsPath}</div>`, NL);
-    fileNode.append('<table border="1">', NL);
-    fileNode.append('<TR><TH>Requirement ID</TH><TH>Testcase ID</TH></TR>', NL);
-    model.requirements.forEach(requirement => {
-        fileNode.append(`<TR><TD>${requirement.name}</TD><TD>`, NL);
-        testModels.forEach(testModel => testModel.tests.forEach(test => {
-            if (test.requirements.map(r => r.ref).includes(requirement)) {
-                fileNode.append(`<div>${test.name} (from ${testModel.$document?.uri.fsPath})<div>`, NL);
-            }
-        }));
-        fileNode.append('</TD></TR>', NL);
-    });
-    fileNode.append('</table>', NL);
-    fileNode.append('</body>', NL);
-    fileNode.append('</html>', NL);
-    return toString(fileNode);
+    /* eslint-disable @typescript-eslint/indent */
+    return toString(
+        expandToNode`
+            <html>
+            <body>
+            <h1>Requirement coverage (demo generator)</h1>
+            <div>Source: ${model.$document?.uri.fsPath}</div>
+            <table border="1">
+            <TR><TH>Requirement ID</TH><TH>Testcase ID</TH></TR>
+            ${joinToNode(
+                model.requirements,
+                requirement => expandToNode`
+                    <TR><TD>${requirement.name}</TD><TD>
+                    ${joinToNode(
+                        testModels.flatMap(testModel => testModel.tests.map(test => ({ testModel, test }))).filter( ({ test }) => test.requirements.map(r => r.ref).includes(requirement) ),
+                        ({ testModel, test }) => `<div>${test.name} (from ${testModel.$document?.uri?.fsPath})<div>`,
+                        { appendNewLineIfNotEmpty: true }
+                    )}
+                    </TD></TR>
+                `,
+                { appendNewLineIfNotEmpty: true }
+            )}
+            </table>
+            </body>
+            </html>
+        `.appendNewLine()
+    );
+    /* eslint-enable @typescript-eslint/indent */
 }
 
 export function generateSummary(model: RequirementModel, testModels: TestModel[], filePath: string, destination: string | undefined): string {

examples/statemachine/src/cli/generator.ts

@@ -6,8 +6,7 @@
 
 import * as fs from 'node:fs';
 import * as path from 'node:path';
-import { expandToNode as toNode, joinToNode as join, toString } from 'langium';
-import type { Generated } from 'langium';
+import { type Generated, expandToNode as toNode, joinToNode as join, toString } from 'langium/generate';
 import type { State, Statemachine } from '../language-server/generated/ast.js';
 import { extractDestinationAndName } from './cli-util.js';
 

examples/statemachine/test/generator.test.ts

@@ -4,12 +4,12 @@
  * terms of the MIT License, which is available in the project root.
  ******************************************************************************/
 
-import type { Generated } from 'langium';
-import type { Statemachine } from '../src/language-server/generated/ast.js';
-import { describe, expect, test } from 'vitest';
-import { EmptyFileSystem, expandToStringWithNL, toString } from 'langium';
+import { EmptyFileSystem } from 'langium';
+import { expandToStringWithNL, toString, type Generated } from 'langium/generate';
 import { parseHelper } from 'langium/test';
+import { describe, expect, test } from 'vitest';
 import { generateCppContent } from '../src/cli/generator.js';
+import type { Statemachine } from '../src/language-server/generated/ast.js';
 import { createStatemachineServices } from '../src/language-server/statemachine-module.js';
 
 describe('Tests the code generator', () => {

packages/generator-langium/templates/cli/src/cli/generator.ts

@@ -1,16 +1,18 @@
 import type { Model } from '../language/generated/ast.js';
+import { expandToNode, joinToNode, toString } from 'langium/generate';
 import * as fs from 'node:fs';
-import { CompositeGeneratorNode, NL, toString } from 'langium';
 import * as path from 'node:path';
 import { extractDestinationAndName } from './cli-util.js';
 
 export function generateJavaScript(model: Model, filePath: string, destination: string | undefined): string {
     const data = extractDestinationAndName(filePath, destination);
     const generatedFilePath = `${path.join(data.destination, data.name)}.js`;
 
-    const fileNode = new CompositeGeneratorNode();
-    fileNode.append('"use strict";', NL, NL);
-    model.greetings.forEach(greeting => fileNode.append(`console.log('Hello, ${greeting.person.ref?.name}!');`, NL));
+    const fileNode = expandToNode`
+        "use strict";
+
+        ${joinToNode(model.greetings, greeting => `console.log('Hello, ${greeting.person.ref?.name}!');`, { appendNewLineIfNotEmpty: true })}
+    `.appendNewLineIfNotEmpty();
 
     if (!fs.existsSync(data.destination)) {
         fs.mkdirSync(data.destination, { recursive: true });

packages/generator-langium/test/yeoman-generator.test.ts

@@ -4,11 +4,11 @@
  * terms of the MIT License, which is available in the project root.
  ******************************************************************************/
 
-import { describe, test } from 'vitest';
-import { normalizeEOL } from 'langium';
-import { createHelpers } from 'yeoman-test';
+import { normalizeEOL } from 'langium/generate';
 import * as path from 'node:path';
 import * as url from 'node:url';
+import { describe, test } from 'vitest';
+import { createHelpers } from 'yeoman-test';
 
 const __dirname = url.fileURLToPath(new URL('../', import.meta.url));