gravlax - npm Package Compare versions

Comparing version 0.11.1 to 0.12.0

lib/ast-printer.js

@@ -34,2 +34,3 @@ import {
   set: (expr) => parenthesize("set", expr.object, expr.name.lexeme, expr.value),
+  super: () => "super",
   this: () => parenthesize("this"),
@@ -36,0 +37,0 @@ unary: (expr) => parenthesize(expr.operator.lexeme, expr.right),

lib/environment.js

 import { RuntimeError } from "./interpreter.js";
 class Environment {
-  #enclosing;
   #values;
+  enclosing;
   constructor(enclosing) {
     this.#values = /* @__PURE__ */ new Map();
-    this.#enclosing = enclosing;
+    this.enclosing = enclosing;
   }
@@ -12,3 +12,3 @@ ancestor(distance) {
     for (let i = 0; i < distance; i++) {
-      const enclosing = env.#enclosing;
+      const enclosing = env.enclosing;
       if (!enclosing) {
@@ -15,0 +15,0 @@ throw new Error("Tried to go past last ancestor!");

lib/interpreter.js

@@ -130,3 +130,17 @@ import { LoxCallable } from "./callable.js";
   class(stmt) {
+    let superclass = null;
+    if (stmt.superclass) {
+      superclass = this.evaluate(stmt.superclass);
+      if (!(superclass instanceof LoxClass)) {
+        throw new RuntimeError(
+          stmt.superclass.name,
+          "Superclass must be a class."
+        );
+      }
+    }
     this.#environment.define(stmt.name.lexeme, null);
+    if (superclass) {
+      this.#environment = new Environment(this.#environment);
+      this.#environment.define("super", superclass);
+    }
     const methods = /* @__PURE__ */ new Map();
@@ -141,3 +155,6 @@ for (const method of stmt.methods) {
     }
-    const klass = new LoxClass(stmt.name.lexeme, methods);
+    const klass = new LoxClass(stmt.name.lexeme, superclass, methods);
+    if (superclass) {
+      this.#environment = this.#environment.enclosing;
+    }
     this.#environment.assign(stmt.name, klass);
@@ -192,2 +209,21 @@ }
       }
+      case "super": {
+        const distance2 = this.#locals.get(expr);
+        const superclass = this.#environment.getAt(
+          distance2,
+          "super"
+        );
+        const object = this.#environment.getAt(
+          distance2 - 1,
+          "this"
+        );
+        const method = superclass.findMethod(expr.method.lexeme);
+        if (!method) {
+          throw new RuntimeError(
+            expr.method,
+            `Undefined property ${expr.method.lexeme}.`
+          );
+        }
+        return method.bindThis(object);
+      }
       case "unary":
@@ -194,0 +230,0 @@ const right = this.evaluate(expr.right);

lib/lox-class.js

@@ -6,6 +6,8 @@ import { LoxCallable } from "./callable.js";
   name;
-  constructor(name, methods) {
+  superclass;
+  constructor(name, superclass, methods) {
     super();
     this.name = name;
     this.#methods = methods;
+    this.superclass = superclass;
   }
@@ -25,3 +27,4 @@ arity() {
   findMethod(name) {
-    return this.#methods.get(name);
+    const meth = this.#methods.get(name);
+    return meth ?? this.superclass?.findMethod(name);
   }
@@ -28,0 +31,0 @@ toString() {

lib/parser.js

@@ -77,2 +77,7 @@ import { errorOnToken } from "./main.js";
     const name = consume("identifier", "Expect class name.");
+    let superclass = null;
+    if (match("<")) {
+      consume("identifier", "Expect superclass name.");
+      superclass = { kind: "var-expr", name: previous() };
+    }
     consume("{", "Expect '{' before class body.");
@@ -84,3 +89,3 @@ const methods = [];
     consume("}", "Expect '}' after class body.");
-    return { kind: "class", methods, name };
+    return { kind: "class", methods, name, superclass };
   };
@@ -288,2 +293,7 @@ const func = (kind) => {
       return { kind: "var-expr", name: previous() };
+    } else if (match("super")) {
+      const keyword = previous();
+      consume(".", "Expect '.' after 'super'.");
+      const method = consume("identifier", "Expect superclass method name.");
+      return { keyword, kind: "super", method };
     }
@@ -290,0 +300,0 @@ throw error(peek(), "Expect expression.");

lib/resolver.js

@@ -79,2 +79,16 @@ import {
       define(stmt.name);
+      if (stmt.superclass && stmt.name.lexeme === stmt.superclass.name.lexeme) {
+        errorOnToken(
+          stmt.superclass.name,
+          "A class can't inherit from itself."
+        );
+      }
+      if (stmt.superclass) {
+        currentClass = "subclass";
+        resolveExpr(stmt.superclass);
+      }
+      if (stmt.superclass) {
+        beginScope();
+        scopes.at(-1).set("super", true);
+      }
       beginScope();
@@ -89,2 +103,5 @@ scopes.at(-1)?.set("this", true);
       endScope();
+      if (stmt.superclass) {
+        endScope();
+      }
       currentClass = encClass;
@@ -140,2 +157,13 @@ },
     },
+    super(expr) {
+      if (currentClass === "none") {
+        errorOnToken(expr.keyword, "Can't use 'super' outside of a class.");
+      } else if (currentClass === "class") {
+        errorOnToken(
+          expr.keyword,
+          "Can't use 'super' in a class with no superclass."
+        );
+      }
+      resolveLocal(expr, expr.keyword);
+    },
     this(expr) {
@@ -142,0 +170,0 @@ if (currentClass === "none") {

package.json

 {
 	"name": "gravlax",
-	"version": "0.11.1",
+	"version": "0.12.0",
 	"description": "A Lox interpreter with tasty TypeScript seasoning",
@@ -87,3 +87,3 @@ "repository": {
 	},
-	"packageManager": "pnpm@8.14.3",
+	"packageManager": "pnpm@8.15.1",
 	"engines": {
@@ -90,0 +90,0 @@ "node": ">=20"

No alert changes

Improved metrics

Total package byte prevSize

141541

increased by5.38%

Lines of code

1557

increased by5.27%

No dependency changes