gravlax - npm Package Compare versions

Comparing version 0.10.0 to 0.11.0

lib/ast-printer.js

@@ -14,2 +14,3 @@ import {
   call: (expr) => parenthesize(expr.callee, ...expr.args),
+  class: (stmt) => parenthesizeText("class", stmt.name.lexeme, "..."),
   expr: (stmt) => visitExpr(stmt.expression, astPrinter),
@@ -21,2 +22,3 @@ func: (stmt) => parenthesizeText(
   ),
+  get: (expr) => parenthesize("get", expr.object, expr.name.lexeme),
   grouping: (expr) => parenthesize("group", expr.expr),
@@ -33,2 +35,4 @@ if: (stmt) => parenthesizeText(
   return: (stmt) => parenthesize("return", ...stmt.value ? [stmt.value] : []),
+  set: (expr) => parenthesize("set", expr.object, expr.name.lexeme, expr.value),
+  this: () => parenthesize("this"),
   unary: (expr) => parenthesize(expr.operator.lexeme, expr.right),
@@ -35,0 +39,0 @@ "var-expr": (expr) => String(expr.name.literal),

lib/interpreter.js

@@ -7,3 +7,5 @@ import {
 import { Environment } from "./environment.js";
+import { LoxClass } from "./lox-class.js";
 import { LoxFunction } from "./lox-function.js";
+import { LoxInstance } from "./lox-instance.js";
 import { isCurrency } from "./lox-value.js";
@@ -160,5 +162,22 @@ import { runtimeError } from "./main.js";
   }
+  class(stmt) {
+    this.#environment.define(stmt.name.lexeme, null);
+    const methods = /* @__PURE__ */ new Map();
+    for (const method of stmt.methods) {
+      const func = new LoxFunction(
+        method,
+        this.#environment,
+        method.name.lexeme === "init"
+      );
+      methods.set(method.name.lexeme, func);
+    }
+    const klass = new LoxClass(stmt.name.lexeme, methods);
+    this.#environment.assign(stmt.name, klass);
+  }
   evaluate(expr) {
     return visitExpr(expr, this);
   }
+  this(expr) {
+    return this.#lookUpVariable(expr.keyword, expr);
+  }
   execute(stmt) {
@@ -182,5 +201,12 @@ visitStmt(stmt, this);
   func(stmt) {
-    const func = new LoxFunction(stmt, this.#environment);
+    const func = new LoxFunction(stmt, this.#environment, false);
     this.#environment.define(stmt.name.lexeme, func);
   }
+  get(expr) {
+    const obj = this.evaluate(expr.object);
+    if (obj instanceof LoxInstance) {
+      return obj.get(expr.name);
+    }
+    throw new RuntimeError(expr.name, "Only instances have properties.");
+  }
   grouping(expr) {
@@ -227,2 +253,11 @@ return this.evaluate(expr.expr);
   }
+  set(expr) {
+    const obj = this.evaluate(expr.object);
+    if (!(obj instanceof LoxInstance)) {
+      throw new RuntimeError(expr.name, "Only instances have fields.");
+    }
+    const value = this.evaluate(expr.value);
+    obj.set(expr.name, value);
+    return value;
+  }
   unary(expr) {
@@ -229,0 +264,0 @@ const right = this.evaluate(expr.right);

lib/lox-function.js

@@ -5,8 +5,10 @@ import { LoxCallable } from "./callable.js";
 class LoxFunction extends LoxCallable {
+  #isInitializer;
   closure;
   declaration;
-  constructor(declaration, closure) {
+  constructor(declaration, closure, isInitializer) {
     super();
     this.declaration = declaration;
     this.closure = closure;
+    this.#isInitializer = isInitializer;
   }
@@ -16,2 +18,7 @@ arity() {
   }
+  bindThis(instance) {
+    const env = new Environment(this.closure);
+    env.define("this", instance);
+    return new LoxFunction(this.declaration, env, this.#isInitializer);
+  }
   // Why, oh why, do I need type annotations here?
@@ -31,2 +38,5 @@ call(interpreter, args) {
     }
+    if (this.#isInitializer) {
+      return this.closure.getAt(0, "this");
+    }
     return null;
@@ -33,0 +43,0 @@ }

lib/parser.js

@@ -59,3 +59,5 @@ import { errorOnToken } from "./main.js";
     try {
-      if (match("fun")) {
+      if (match("class")) {
+        return classDecl();
+      } else if (match("fun")) {
         return func("function");
@@ -74,2 +76,12 @@ } else if (match("var")) {
   };
+  const classDecl = () => {
+    const name = consume("identifier", "Expect class name.");
+    consume("{", "Expect '{' before class body.");
+    const methods = [];
+    while (!check("}") && !isAtEnd()) {
+      methods.push(func("method"));
+    }
+    consume("}", "Expect '}' after class body.");
+    return { kind: "class", methods, name };
+  };
   const func = (kind) => {
@@ -199,2 +211,4 @@ const name = consume("identifier", `Expect ${kind} name.`);
         return { kind: "assign", name, value };
+      } else if (expr.kind == "get") {
+        return { ...expr, kind: "set", value };
       }
@@ -236,2 +250,5 @@ error(equals, "Invalid assignment target.");
         expr = finishCall(expr);
+      } else if (match(".")) {
+        const name = consume("identifier", "Expect property name after '.'.");
+        expr = { kind: "get", name, object: expr };
       } else {
@@ -269,2 +286,4 @@ break;
       return { expr, kind: "grouping" };
+    } else if (match("this")) {
+      return { keyword: previous(), kind: "this" };
     } else if (match("identifier")) {
@@ -271,0 +290,0 @@ return { kind: "var-expr", name: previous() };

lib/resolver.js

@@ -9,2 +9,3 @@ import {
   let currentFunc = "none";
+  let currentClass = "none";
   const beginScope = () => {
@@ -74,2 +75,18 @@ scopes.push(/* @__PURE__ */ new Map());
     },
+    class(stmt) {
+      const encClass = currentClass;
+      currentClass = "class";
+      declare(stmt.name);
+      define(stmt.name);
+      beginScope();
+      scopes.at(-1)?.set("this", true);
+      for (const method of stmt.methods) {
+        resolveFunction(
+          method,
+          method.name.lexeme === "init" ? "initializer" : "method"
+        );
+      }
+      endScope();
+      currentClass = encClass;
+    },
     expr(stmt) {
@@ -83,2 +100,5 @@ resolveExpr(stmt.expression);
     },
+    get(expr) {
+      resolveExpr(expr.object);
+    },
     grouping(expr) {
@@ -108,5 +128,22 @@ resolveExpr(expr.expr);
       if (stmt.value) {
+        if (currentFunc === "initializer") {
+          errorOnToken(
+            stmt.keyword,
+            "Can't return a value from an initializer."
+          );
+        }
         resolveExpr(stmt.value);
       }
     },
+    set(expr) {
+      resolveExpr(expr.value);
+      resolveExpr(expr.object);
+    },
+    this(expr) {
+      if (currentClass === "none") {
+        errorOnToken(expr.keyword, "Can't use 'this' outside of a class.");
+        this.return;
+      }
+      resolveLocal(expr, expr.keyword);
+    },
     unary(expr) {
@@ -113,0 +150,0 @@ resolveExpr(expr.right);

package.json

 {
 	"name": "gravlax",
-	"version": "0.10.0",
+	"version": "0.11.0",
 	"description": "A Lox interpreter with tasty TypeScript seasoning",
@@ -24,2 +24,3 @@ "repository": {
 		"build": "tsup",
+		"coverage": "pnpm test -- --coverage --no-watch",
 		"format": "prettier \"**/*\" --ignore-unknown",
@@ -86,3 +87,3 @@ "lint": "eslint . .*js --max-warnings 0",
 	},
-	"packageManager": "pnpm@8.14.1",
+	"packageManager": "pnpm@8.14.3",
 	"engines": {
@@ -89,0 +90,0 @@ "node": ">=20"

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Improved metrics

Total package byte prevSize

133105

increased by12.93%

Number of package files

39

increased by11.43%

Lines of code

1478

increased by12.65%

No dependency changes