gravlax - npm Package Compare versions

Comparing version 0.7.0 to 0.8.0

lib/ast-printer.js

@@ -12,3 +12,9 @@ import {
   ),
+  call: (expr) => parenthesize(expr.callee, ...expr.args),
   expr: (stmt) => visitExpr(stmt.expression, astPrinter),
+  func: (stmt) => parenthesizeText(
+    "func",
+    parenthesizeText(stmt.name.lexeme, ...stmt.params.map((p) => p.lexeme)),
+    visitStmt({ kind: "block", statements: stmt.body }, astPrinter)
+  ),
   grouping: (expr) => parenthesize("group", expr.expr),
@@ -24,2 +30,3 @@ if: (stmt) => parenthesizeText(
   print: (stmt) => parenthesize("print", stmt.expression),
+  return: (stmt) => parenthesize("return", ...stmt.value ? [stmt.value] : []),
   unary: (expr) => parenthesize(expr.operator.lexeme, expr.right),
@@ -41,4 +48,4 @@ "var-expr": (expr) => String(expr.name.literal),
 }
-function parenthesize(name, ...exprs) {
-  const parts = [name];
+function parenthesize(...exprs) {
+  const parts = [];
   for (const expr of exprs) {
@@ -45,0 +52,0 @@ parts.push(typeof expr == "string" ? expr : visitExpr(expr, astPrinter));

lib/interpreter.js

@@ -5,6 +5,34 @@ import {
 } from "./ast.js";
+import { LoxCallable } from "./callable.js";
 import { Environment } from "./environment.js";
+import { LoxFunction } from "./lox-function.js";
 import { runtimeError } from "./main.js";
+class ClockFn extends LoxCallable {
+  arity() {
+    return 0;
+  }
+  call() {
+    return Date.now();
+  }
+  toString() {
+    return "<native fn>";
+  }
+}
+class ReturnCall extends Error {
+  value;
+  constructor(value) {
+    super();
+    this.value = value;
+  }
+}
 class Interpreter {
-  #environment = new Environment();
+  globals = new Environment();
+  #environment = this.globals;
+  constructor() {
+    this.globals.define("clock", new ClockFn());
+  }
+  return(stmt) {
+    const value = stmt.value && this.evaluate(stmt.value);
+    throw new ReturnCall(value);
+  }
   "var-expr"(expr) {
@@ -79,2 +107,19 @@ return this.#environment.get(expr.name);
   }
+  call(expr) {
+    const callee = this.evaluate(expr.callee);
+    const args = expr.args.map((arg) => this.evaluate(arg));
+    if (!(callee instanceof LoxCallable)) {
+      throw new RuntimeError(
+        expr.paren,
+        "Can only call functions and classes."
+      );
+    }
+    if (args.length != callee.arity()) {
+      throw new RuntimeError(
+        expr.paren,
+        `Expected ${callee.arity()} arguments but got ${args.length}.`
+      );
+    }
+    return callee.call(this, args);
+  }
   evaluate(expr) {
@@ -100,2 +145,6 @@ return visitExpr(expr, this);
   }
+  func(stmt) {
+    const func = new LoxFunction(stmt, this.#environment);
+    this.#environment.define(stmt.name.lexeme, func);
+  }
   grouping(expr) {
@@ -186,2 +235,4 @@ return this.evaluate(expr.expr);
     return "nil";
+  } else if (val === void 0) {
+    throw new Error(`undefined is not a valid Lox value`);
   }
@@ -192,2 +243,3 @@ return String(val);
   Interpreter,
+  ReturnCall,
   RuntimeError,
@@ -194,0 +246,0 @@ isEqual,

lib/parser.js

@@ -59,3 +59,5 @@ import { errorOnToken } from "./main.js";
     try {
-      if (match("var")) {
+      if (match("fun")) {
+        return func("function");
+      } else if (match("var")) {
         return varDeclaration();
@@ -72,2 +74,19 @@ }
   };
+  const func = (kind) => {
+    const name = consume("identifier", `Expect ${kind} name.`);
+    consume("(", "Expect '(' after ${kind} name.");
+    const params = [];
+    if (!check(")")) {
+      do {
+        if (params.length >= 255) {
+          error(peek(), "Can't have more than 255 parameters.");
+        }
+        params.push(consume("identifier", "Expect parameter name."));
+      } while (match(","));
+    }
+    consume(")", "Expect ')' after parameters.");
+    consume("{", `Expect '{' before ${kind} body.`);
+    const body = block();
+    return { body, kind: "func", name, params };
+  };
   const varDeclaration = () => {
@@ -89,2 +108,4 @@ const name = consume("identifier", "Expect variable name.");
       return printStatement();
+    } else if (match("return")) {
+      return returnStatement();
     } else if (match("while")) {
@@ -150,2 +171,11 @@ return whileStatement();
   };
+  const returnStatement = () => {
+    const keyword = previous();
+    let value = null;
+    if (!check(";")) {
+      value = expression();
+    }
+    consume(";", "Expect ';' after return value.");
+    return { keyword, kind: "return", value };
+  };
   const block = () => {
@@ -200,4 +230,28 @@ const statements = [];
     }
-    return primary();
+    return call();
   };
+  const call = () => {
+    let expr = primary();
+    while (true) {
+      if (match("(")) {
+        expr = finishCall(expr);
+      } else {
+        break;
+      }
+    }
+    return expr;
+  };
+  const finishCall = (callee) => {
+    const args = [];
+    if (!check(")")) {
+      do {
+        if (args.length >= 255) {
+          error(peek(), "Can't have more than 255 arguments.");
+        }
+        args.push(expression());
+      } while (match(","));
+    }
+    const paren = consume(")", "Expect ')' after arguments.");
+    return { args, callee, kind: "call", paren };
+  };
   const primary = () => {
@@ -204,0 +258,0 @@ if (match("false")) {

lib/scanner.js

@@ -64,3 +64,4 @@ import { error } from "./main.js";
     const isCurrency = this.source[this.start] === "$";
-    while (isDigit(this.#peek()) || this.#peek() === ",") {
+    while (isDigit(this.#peek()) || // a trailing comma might be part of an argument list.
+    this.#peek() === "," && isDigit(this.#peekNext())) {
       this.#advance();
@@ -67,0 +68,0 @@ }

package.json

 {
 	"name": "gravlax",
-	"version": "0.7.0",
+	"version": "0.8.0",
 	"description": "A Lox interpreter with tasty TypeScript seasoning",
@@ -31,3 +31,3 @@ "repository": {
 		"lint:spelling": "cspell \"**\" \".github/**/*\"",
-		"pre-push": "pnpm run '/^lint(?!:packages).*$/'",
+		"pre-push": "pnpm run '/^(tsc|lint(?!:packages).*)$/'",
 		"prepare": "husky install",
@@ -34,0 +34,0 @@ "repl": "pnpm run:ts src/index.ts",

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Improved metrics

Total package byte prevSize

91920

increased by17.62%

Number of package files

29

increased by16%

Lines of code

1015

increased by18.02%

No dependency changes