feat: very basic type computer (#596)

Closes partially #541

### Summary of Changes

Add a very basic implementation of a type computer that can only deal
with literals and template strings. It does, however, lay the groundwork
to implement more complex features later, by adding a system to access
builtin classes like `String` and registering the type computer as an
added service.

---------

Co-authored-by: megalinter-bot <129584137+megalinter-bot@users.noreply.github.com>

src/language/builtins/fileFinder.ts

@@ -0,0 +1,37 @@
+import path from 'path';
+import { URI } from 'langium';
+import { SAFE_DS_FILE_EXTENSIONS } from '../helpers/fileExtensions.js';
+import { globSync } from 'glob';
+
+let builtinsPath: string;
+if (__filename.endsWith('.ts')) {
+    // Before running ESBuild
+    builtinsPath = path.join(__dirname, '..', '..', 'resources', 'builtins');
+} /* c8 ignore start */ else {
+    // After running ESBuild
+    builtinsPath = path.join(__dirname, '..', 'resources', 'builtins');
+} /* c8 ignore stop */
+
+/**
+ * Lists all Safe-DS files in `src/resources/builtins`.
+ *
+ * @return URIs of all discovered files.
+ */
+export const listBuiltinsFiles = (): URI[] => {
+    const pattern = `**/*.{${SAFE_DS_FILE_EXTENSIONS.join(',')}}`;
+    const relativePaths = globSync(pattern, { cwd: builtinsPath, nodir: true });
+    return relativePaths.map((relativePath) => {
+        const absolutePath = path.join(builtinsPath, relativePath);
+        return URI.file(absolutePath);
+    });
+};
+
+/**
+ * Resolves a relative path to a builtin file.
+ *
+ * @param relativePath
+ */
+export const resolveRelativePathToBuiltinFile = (relativePath: string): URI => {
+    const absolutePath = path.join(builtinsPath, relativePath);
+    return URI.file(absolutePath);
+};

src/language/builtins/safe-ds-core-classes.ts

@@ -0,0 +1,93 @@
+import { SafeDsServices } from '../safe-ds-module.js';
+import { resolveRelativePathToBuiltinFile } from './fileFinder.js';
+import { isSdsClass, isSdsModule, SdsClass } from '../generated/ast.js';
+import { LangiumDocuments } from 'langium';
+import { moduleMembersOrEmpty } from '../helpers/shortcuts.js';
+
+const CORE_CLASSES_URI = resolveRelativePathToBuiltinFile('safeds/lang/coreClasses.sdsstub');
+
+export class SafeDsCoreClasses {
+    private readonly langiumDocuments: LangiumDocuments;
+
+    constructor(services: SafeDsServices) {
+        this.langiumDocuments = services.shared.workspace.LangiumDocuments;
+    }
+
+    private cachedAny: SdsClass | undefined;
+
+    /* c8 ignore start */
+    get Any(): SdsClass | undefined {
+        if (!this.cachedAny) {
+            this.cachedAny = this.getClass('Any');
+        }
+        return this.cachedAny;
+    }
+
+    private cachedBoolean: SdsClass | undefined;
+    /* c8 ignore stop */
+
+    get Boolean(): SdsClass | undefined {
+        if (!this.cachedBoolean) {
+            this.cachedBoolean = this.getClass('Boolean');
+        }
+        return this.cachedBoolean;
+    }
+
+    private cachedFloat: SdsClass | undefined;
+
+    get Float(): SdsClass | undefined {
+        if (!this.cachedFloat) {
+            this.cachedFloat = this.getClass('Float');
+        }
+        return this.cachedFloat;
+    }
+
+    private cachedInt: SdsClass | undefined;
+
+    get Int(): SdsClass | undefined {
+        if (!this.cachedInt) {
+            this.cachedInt = this.getClass('Int');
+        }
+        return this.cachedInt;
+    }
+
+    private cachedNothing: SdsClass | undefined;
+
+    get Nothing(): SdsClass | undefined {
+        if (!this.cachedNothing) {
+            this.cachedNothing = this.getClass('Nothing');
+        }
+        return this.cachedNothing;
+    }
+
+    private cachedString: SdsClass | undefined;
+
+    get String(): SdsClass | undefined {
+        if (!this.cachedString) {
+            this.cachedString = this.getClass('String');
+        }
+        return this.cachedString;
+    }
+
+    private getClass(name: string): SdsClass | undefined {
+        if (!this.langiumDocuments.hasDocument(CORE_CLASSES_URI)) {
+            /* c8 ignore next 2 */
+            return undefined;
+        }
+
+        const document = this.langiumDocuments.getOrCreateDocument(CORE_CLASSES_URI);
+        const root = document.parseResult.value;
+        if (!isSdsModule(root)) {
+            /* c8 ignore next 2 */
+            return undefined;
+        }
+
+        const firstMatchingModuleMember = moduleMembersOrEmpty(root).find((m) => m.name === name);
+        if (!isSdsClass(firstMatchingModuleMember)) {
+            /* c8 ignore next 2 */
+            return undefined;
+        }
+
+        return firstMatchingModuleMember;
+    }
+}

src/language/builtins/safe-ds-workspace-manager.ts

@@ -1,8 +1,6 @@
-import { DefaultWorkspaceManager, LangiumDocument, LangiumDocumentFactory, LangiumSharedServices, URI } from 'langium';
+import { DefaultWorkspaceManager, LangiumDocument, LangiumDocumentFactory, LangiumSharedServices } from 'langium';
 import { WorkspaceFolder } from 'vscode-languageserver';
-import { SAFE_DS_FILE_EXTENSIONS } from '../helpers/fileExtensions.js';
-import { globSync } from 'glob';
-import path from 'path';
+import { listBuiltinsFiles } from './fileFinder.js';
 
 export class SafeDsWorkspaceManager extends DefaultWorkspaceManager {
     private documentFactory: LangiumDocumentFactory;
@@ -18,31 +16,9 @@ export class SafeDsWorkspaceManager extends DefaultWorkspaceManager {
     ): Promise<void> {
         await super.loadAdditionalDocuments(folders, collector);
 
+        // Load builtin files
         for (const uri of listBuiltinsFiles()) {
             collector(this.documentFactory.create(uri));
         }
     }
 }
-
-let builtinsPath: string;
-if (__filename.endsWith('.ts')) {
-    // Before running ESBuild
-    builtinsPath = path.join(__dirname, '..', '..', 'resources', 'builtins');
-} /* c8 ignore start */ else {
-    // After running ESBuild
-    builtinsPath = path.join(__dirname, '..', 'resources', 'builtins');
-} /* c8 ignore stop */
-
-/**
- * Lists all Safe-DS files in `src/resources/builtins`.
- *
- * @return URIs of all discovered files.
- */
-export const listBuiltinsFiles = (): URI[] => {
-    const pattern = `**/*.{${SAFE_DS_FILE_EXTENSIONS.join(',')}}`;
-    const relativePaths = globSync(pattern, { cwd: builtinsPath, nodir: true });
-    return relativePaths.map((relativePath) => {
-        const absolutePath = path.join(builtinsPath, relativePath);
-        return URI.file(absolutePath);
-    });
-};

src/language/helpers/shortcuts.ts

@@ -3,6 +3,7 @@ import {
     isSdsBlockLambdaResult,
     isSdsDeclaration,
     isSdsModule,
+    isSdsModuleMember,
     isSdsPlaceholder,
     SdsAnnotatedObject,
     SdsAnnotationCall,
@@ -19,6 +20,7 @@ import {
     SdsLiteral,
     SdsLiteralType,
     SdsModule,
+    SdsModuleMember,
     SdsParameter,
     SdsParameterList,
     SdsPlaceholder,
@@ -77,6 +79,10 @@ export const importsOrEmpty = function (node: SdsModule | undefined): SdsImport[
     return node?.imports ?? [];
 };
 
+export const moduleMembersOrEmpty = function (node: SdsModule | undefined): SdsModuleMember[] {
+    return node?.members?.filter(isSdsModuleMember) ?? [];
+};
+
 export const packageNameOrNull = function (node: AstNode | undefined): string | null {
     return getContainerOfType(node, isSdsModule)?.name ?? null;
 };

src/language/safe-ds-module.ts

@@ -10,19 +10,24 @@ import {
     PartialLangiumServices,
 } from 'langium';
 import { SafeDsGeneratedModule, SafeDsGeneratedSharedModule } from './generated/module.js';
-import { registerValidationChecks, SafeDsValidator } from './validation/safe-ds-validator.js';
+import { registerValidationChecks } from './validation/safe-ds-validator.js';
 import { SafeDsFormatter } from './formatting/safe-ds-formatter.js';
 import { SafeDsWorkspaceManager } from './builtins/safe-ds-workspace-manager.js';
 import { SafeDsScopeComputation } from './scoping/safe-ds-scope-computation.js';
 import { SafeDsScopeProvider } from './scoping/safe-ds-scope-provider.js';
 import { SafeDsValueConverter } from './grammar/safe-ds-value-converter.js';
+import { SafeDsTypeComputer } from './typing/safe-ds-type-computer.js';
+import { SafeDsCoreClasses } from './builtins/safe-ds-core-classes.js';
 
 /**
  * Declaration of custom services - add your own service classes here.
  */
 export type SafeDsAddedServices = {
-    validation: {
-        SafeDsValidator: SafeDsValidator;
+    builtins: {
+        CoreClasses: SafeDsCoreClasses;
+    };
+    types: {
+        TypeComputer: SafeDsTypeComputer;
     };
 };
 
@@ -38,6 +43,9 @@ export type SafeDsServices = LangiumServices & SafeDsAddedServices;
  * selected services, while the custom services must be fully specified.
  */
 export const SafeDsModule: Module<SafeDsServices, PartialLangiumServices & SafeDsAddedServices> = {
+    builtins: {
+        CoreClasses: (services) => new SafeDsCoreClasses(services),
+    },
     lsp: {
         Formatter: () => new SafeDsFormatter(),
     },
@@ -48,8 +56,8 @@ export const SafeDsModule: Module<SafeDsServices, PartialLangiumServices & SafeD
         ScopeComputation: (services) => new SafeDsScopeComputation(services),
         ScopeProvider: (services) => new SafeDsScopeProvider(services),
     },
-    validation: {
-        SafeDsValidator: () => new SafeDsValidator(),
+    types: {
+        TypeComputer: (services) => new SafeDsTypeComputer(services),
     },
 };
 

src/language/scoping/safe-ds-scope-provider.ts

@@ -1,14 +1,12 @@
 import {
     AstNode,
     AstNodeDescription,
-    AstNodeDescriptionProvider,
     AstNodeLocator,
     DefaultScopeProvider,
     EMPTY_SCOPE,
     getContainerOfType,
     getDocument,
     LangiumDocuments,
-    LangiumServices,
     MultiMap,
     ReferenceInfo,
     Scope,
@@ -59,18 +57,20 @@ import {
 } from '../helpers/shortcuts.js';
 import { isContainedIn } from '../helpers/ast.js';
 import { isStatic, isWildcardImport } from '../helpers/checks.js';
+import { SafeDsServices } from '../safe-ds-module.js';
+import { SafeDsTypeComputer } from '../typing/safe-ds-type-computer.js';
 
 export class SafeDsScopeProvider extends DefaultScopeProvider {
-    readonly documents: LangiumDocuments;
-    readonly astNodeDescriptionProvider: AstNodeDescriptionProvider;
-    readonly astNodeLocator: AstNodeLocator;
+    private readonly astNodeLocator: AstNodeLocator;
+    private readonly langiumDocuments: LangiumDocuments;
+    private readonly typeComputer: SafeDsTypeComputer;
 
-    constructor(services: LangiumServices) {
+    constructor(services: SafeDsServices) {
         super(services);
 
-        this.documents = services.shared.workspace.LangiumDocuments;
-        this.astNodeDescriptionProvider = services.workspace.AstNodeDescriptionProvider;
         this.astNodeLocator = services.workspace.AstNodeLocator;
+        this.langiumDocuments = services.shared.workspace.LangiumDocuments;
+        this.typeComputer = services.types.TypeComputer;
     }
 
     override getScope(context: ReferenceInfo): Scope {
@@ -388,7 +388,7 @@ export class SafeDsScopeProvider extends DefaultScopeProvider {
             /* c8 ignore next 2 */
             return nodeDescription.node;
         }
-        const document = this.documents.getOrCreateDocument(nodeDescription.documentUri);
+        const document = this.langiumDocuments.getOrCreateDocument(nodeDescription.documentUri);
         return this.astNodeLocator.getAstNode(document.parseResult.value, nodeDescription.path);
     }