Add support for modules that import other Pkl modules

codegen/snippet-tests/input/10-namedMod.pkl

@@ -0,0 +1,3 @@
+module n10.pkl.typescript.tests.namedModule
+
+x: String

codegen/snippet-tests/input/11-withImport.pkl

@@ -0,0 +1,3 @@
+import "support/moduleWithClass.pkl"
+
+value: moduleWithClass.ExampleClass

codegen/snippet-tests/input/support/moduleWithClass.pkl

@@ -0,0 +1,4 @@
+class ExampleClass {
+  x: String
+  y: Int
+}

codegen/snippet-tests/output/11_with_import.pkl.ts

@@ -0,0 +1,33 @@
+// This file was generated by `pkl-typescript` from Pkl module `11-withImport`.
+// DO NOT EDIT.
+import * as pklTypescript from "@pkl-community/pkl-typescript"
+
+// Ref: Module root.
+export interface N11WithImport {
+  value: ExampleClass
+}
+
+// Ref: Pkl class `moduleWithClass.ExampleClass`.
+export interface ExampleClass {
+  x: string
+
+  y: number
+}
+
+// Ref: Module root.
+export interface ModuleWithClass {
+}
+
+// LoadFromPath loads the pkl module at the given path and evaluates it into a N11WithImport
+export const loadFromPath = async (path: string): Promise<N11WithImport> => {
+  const evaluator = await pklTypescript.newEvaluator(pklTypescript.PreconfiguredOptions);
+  try {
+    const result = await load(evaluator, pklTypescript.FileSource(path));
+    return result
+  } finally {
+    evaluator.close()
+  }
+};
+
+export const load = (evaluator: pklTypescript.Evaluator, source: pklTypescript.ModuleSource): Promise<N11WithImport> =>
+  evaluator.evaluateModule(source) as Promise<N11WithImport>;

codegen/snippet-tests/output/n10_pkl_typescript_tests_named_module.pkl.ts

@@ -0,0 +1,22 @@
+// This file was generated by `pkl-typescript` from Pkl module `n10.pkl.typescript.tests.namedModule`.
+// DO NOT EDIT.
+import * as pklTypescript from "@pkl-community/pkl-typescript"
+
+// Ref: Module root.
+export interface NamedModule {
+  x: string
+}
+
+// LoadFromPath loads the pkl module at the given path and evaluates it into a NamedModule
+export const loadFromPath = async (path: string): Promise<NamedModule> => {
+  const evaluator = await pklTypescript.newEvaluator(pklTypescript.PreconfiguredOptions);
+  try {
+    const result = await load(evaluator, pklTypescript.FileSource(path));
+    return result
+  } finally {
+    evaluator.close()
+  }
+};
+
+export const load = (evaluator: pklTypescript.Evaluator, source: pklTypescript.ModuleSource): Promise<NamedModule> =>
+  evaluator.evaluateModule(source) as Promise<NamedModule>;

codegen/src/Generator.pkl

@@ -51,7 +51,7 @@ local modules = allMappings
   .mapValues((`_moduleName`: String?, _mappings: List<TypescriptMapping>) -> new TypescriptModule {
     typescriptModule = _moduleName
     `module` = _mappings.first.source.enclosingDeclaration
-    mappings = allMappings
+    mappings = _mappings
   })
 
 output {

codegen/src/internal/ClassGen.pkl

@@ -15,11 +15,6 @@ classInfo: TypescriptMapping.Class = mapping as TypescriptMapping.Class
 local isModule: Boolean = clazz.enclosingDeclaration.moduleClass == clazz
 
 contents = new Listing {
-  when (!imports.isEmpty) {
-    utils.renderImports(imports)
-    ""
-  }
-
   when (interface != null) {
     if (isModule) "// Ref: Module root." else "// Ref: Pkl class `\(clazz.enclosingDeclaration.name).\(clazz.name)`."
 
@@ -35,13 +30,12 @@ local superClass: TypescriptMapping.Class? = mappings.findOrNull((c) -> c is Typ
 
 local fields: Map<String, TypescriptInterfaceProperty> = getFields(clazz, mappings)
 
-local imports =
+imports =
   fields.values
     .flatMap((f) -> f.type.imports)
     .filter((i) -> i != classInfo.typescriptModule).distinct
   + (if (superClass != null && superClass.typescriptModule != classInfo.typescriptModule) List(superClass.typescriptModule) else List())
   + (if (isModule && !isAbstract)
-    // List("../src")
     List("@pkl-community/pkl-typescript")
     else List())
 
@@ -61,11 +55,11 @@ local function isSameType(typeA: reflect.Type, typeB: reflect.Type) =
     true
   else if (typeA is reflect.StringLiteralType && typeB is reflect.StringLiteralType)
     typeA.value == typeB.value
-  // union types turn into Go's `any`, so we can say that this is always fine.
-  // TODO(Jason): this was true in Go, what does it mean here?
-  // TODO(Jason): need to figure out how to deep-check union types structures??
   else if (typeA is reflect.UnionType && typeB is reflect.UnionType)
-    true
+    typeA.members.length == typeB.members.length &&
+    typeA.members
+      .zip(typeB.members)
+      .every((pair) -> isSameType(pair.first, pair.second))
   // remaining types: `FunctionType`, `TypeParameter`, `ModuleType`.
   // we can actually check if `ModuleType` refers to the same type by checking if the enclosing declaration is the same,
   // but we will pretend it is always false for now.
@@ -88,11 +82,10 @@ function getFields(
           // Okay if the property is overridden but does not define a type, but don't render as its own field.
           // E.g. `class Foo extends Bar { bar = "mybar" }`
           else if (prop.type is reflect.UnknownType) !isSuperOpen
-          // Otherwise, the property's type has been overridden and this is impossible to
-          // represent in Go.
-          // TODO(Jason): I think this _can_ be handled by how TypeScript does interface inheritance.
+          // Otherwise, the property's type has been overridden, and this is currently
+          // not supported - would require something like `extends Omit<ParentClass, 'overriddenField'>`
           else throw("""
-              Illegal: Class `\(clazz.reflectee)` overrides property `\(propName)`. This is not supported when generating Go.
+              Illegal: Class `\(clazz.reflectee)` overrides property `\(propName)`. This is not supported when generating TypeScript.
 
               \(prop.location.displayUri)
               """)

codegen/src/internal/TypescriptModule.pkl

@@ -60,14 +60,22 @@ local generated: List<Gen>(hasUniqueNames()) =
         mapping = it
       }
   )
-  // If not a class, what then?
+
+local imports = generated
+  .filter((it) -> it is ClassGen)
+  .map((it) -> it.imports)
+  .flatten()
+  .distinct
 
 contents: String = new Listing {
   """
   // This file was generated by `pkl-typescript` from Pkl module `\(`module`.moduleClass.enclosingDeclaration.name)`.
   // DO NOT EDIT.
   """
 
+  utils.renderImports(imports)
+  ""
+
   for (gen in generated) {
     gen.contents
     ""