From 088b1d301a051a7f5977c40dd114cf58d94a9b24 Mon Sep 17 00:00:00 2001
From: Drew Youngwerth <drew@youngwerth.com>
Date: Sat, 31 Aug 2024 15:08:18 -0700
Subject: [PATCH] Support nominal object initialization

---
 src/semantics/init-entities.ts        | 42 ++++++++++++++++++++-------
 src/semantics/init-primitive-types.ts |  2 ++
 src/syntax-objects/list.ts            |  7 +++++
 src/syntax-objects/types.ts           |  9 +++---
 4 files changed, 45 insertions(+), 15 deletions(-)

diff --git a/src/semantics/init-entities.ts b/src/semantics/init-entities.ts
index f8794e4c..6d1dc7de 100644
--- a/src/semantics/init-entities.ts
+++ b/src/semantics/init-entities.ts
@@ -40,10 +40,16 @@ export const initEntities: SemanticProcessor = (expr) => {
     return initTypeAlias(expr);
   }
 
+  // Object literal
   if (expr.calls("object")) {
     return initObjectLiteral(expr);
   }
 
+  // Nominal object definition
+  if (expr.calls("obj")) {
+    return initNominalObjectType(expr);
+  }
+
   return initCall(expr);
 };
 
@@ -228,22 +234,36 @@ const initTypeExprEntities = (type?: Expr): Expr | undefined => {
   throw new Error("Invalid type entity");
 };
 
+const initNominalObjectType = (obj: List) => {
+  const hasExtension = obj.optionalIdentifierAt(2)?.is("extends");
+  return new ObjectType({
+    ...obj.metadata,
+    name: obj.identifierAt(1),
+    parentObjExpr: hasExtension ? obj.at(3) : undefined,
+    value: extractObjectFields(hasExtension ? obj.listAt(4) : obj.listAt(2)),
+  });
+};
+
 const initObjectType = (obj: List) => {
   return new ObjectType({
     ...obj.metadata,
     name: obj.syntaxId.toString(),
-    value: obj.sliceAsArray(1).map((v) => {
-      if (!v.isList()) {
-        throw new Error("Invalid object field");
-      }
-      const name = v.identifierAt(1);
-      const typeExpr = initTypeExprEntities(v.at(2));
+    value: extractObjectFields(obj),
+  });
+};
 
-      if (!name || !typeExpr) {
-        throw new Error("Invalid object field");
-      }
+const extractObjectFields = (obj: List) => {
+  return obj.sliceAsArray(1).map((v) => {
+    if (!v.isList()) {
+      throw new Error("Invalid object field");
+    }
+    const name = v.identifierAt(1);
+    const typeExpr = initTypeExprEntities(v.at(2));
 
-      return { name: name.value, typeExpr };
-    }),
+    if (!name || !typeExpr) {
+      throw new Error("Invalid object field");
+    }
+
+    return { name: name.value, typeExpr };
   });
 };
diff --git a/src/semantics/init-primitive-types.ts b/src/semantics/init-primitive-types.ts
index 4f56815f..a12ca346 100644
--- a/src/semantics/init-primitive-types.ts
+++ b/src/semantics/init-primitive-types.ts
@@ -1,4 +1,5 @@
 import { i32, f32, i64, f64, bool, dVoid } from "../syntax-objects/types.js";
+import { voidBaseObject } from "../syntax-objects/types.js";
 import { SemanticProcessor } from "./types.js";
 
 export const initPrimitiveTypes: SemanticProcessor = (expr) => {
@@ -8,5 +9,6 @@ export const initPrimitiveTypes: SemanticProcessor = (expr) => {
   expr.registerEntity(f64);
   expr.registerEntity(bool);
   expr.registerEntity(dVoid);
+  expr.registerEntity(voidBaseObject);
   return expr;
 };
diff --git a/src/syntax-objects/list.ts b/src/syntax-objects/list.ts
index f093dae6..639c8191 100644
--- a/src/syntax-objects/list.ts
+++ b/src/syntax-objects/list.ts
@@ -57,6 +57,13 @@ export class List extends Syntax {
     return id;
   }
 
+  optionalIdentifierAt(index: number): Identifier | undefined {
+    const id = this.at(index);
+    if (id?.isIdentifier()) {
+      return id;
+    }
+  }
+
   listAt(index: number): List {
     const id = this.at(index);
     if (!id?.isList()) {
diff --git a/src/syntax-objects/types.ts b/src/syntax-objects/types.ts
index d7257540..651acea6 100644
--- a/src/syntax-objects/types.ts
+++ b/src/syntax-objects/types.ts
@@ -163,6 +163,7 @@ export type ObjectField = { name: string; typeExpr: Expr; type?: Type };
 export class ObjectType extends BaseType {
   readonly kindOfType = "object";
   fields: ObjectField[];
+  parentObjExpr?: Expr;
   parentObj?: ObjectType;
   /** Type used for locals, globals, function return type */
   binaryenType?: number;
@@ -170,13 +171,14 @@ export class ObjectType extends BaseType {
   constructor(
     opts: NamedEntityOpts & {
       value: ObjectField[];
-      parentObj?: ObjectType | null;
+      parentObjExpr?: Expr;
+      parentObj?: ObjectType;
     }
   ) {
     super(opts);
     this.fields = opts.value;
-    this.parentObj =
-      opts.parentObj !== null ? opts.parentObj ?? voidBaseObject : undefined;
+    this.parentObj = opts.parentObj;
+    this.parentObjExpr = opts.parentObjExpr;
   }
 
   get size() {
@@ -293,6 +295,5 @@ export const dVoid = PrimitiveType.from("void");
 export const voidBaseObject = new ObjectType({
   name: "Object",
   value: [],
-  parentObj: null,
 });
 export const CDT_ADDRESS_TYPE = i32;