Enichan · December 16, 2021 21:38
diff --git a/interpretoy.html b/interpretoy.html
 <html>
 <head>
 <title>Interpretoy REPL</title>
 </head>
 <body>

 <script>
 // based on lispy by Peter Norvig: http://norvig.com/lispy.html

 function load(source) {
    return parse(tokenize(source));
 }

 function tokenize(source) {
    return source.replaceAll("'", " ' ").replaceAll("(", " ( ").replaceAll(")", " ) ").replaceAll("\n", "").replaceAll("\r", "").replaceAll("\t", "").split(" ").filter(i => i);
 }

 function parse(tokens) {
    if (!tokens.length) {
        throw new Error("Unexpected EOF");
    }
    let token = tokens.shift();
    if (token === "(") {
        let l = [];
        while (tokens[0] !== ")") {
            l.push(parse(tokens));
        }
        tokens.shift();
        return l;
    }
    else if (token === "'") {
        let next = parse(tokens);
        return [ "quote", next ];
    }
    else if (token === ")") {
        throw new Error("Unexpected ')'");
    }
    else {
        return atom(token);
    }
 }

 function atom(token) {
    let num = token * 1;
    if (num || num === 0) {
        return num;
    }
    return token;
 }

 function toLispString(l, s) {
    return [l].map(function join(v) { 
        return Array.isArray(v) ? "(" + v.map(join).join(" ") + ")" : v;
    }).join(" ");
 }

 function makeEnv() {
    var env = new Env();
    Object.getOwnPropertyNames(Math).forEach(property => {
        if(typeof Math[property] === 'function') {
            env[property] = Math[property];
        }
    });
    [ ["+"], ["-"], ["*"], ["/"], ["<"], ["<="], [">"], [">="], [ "=", "===" ], [ "|" ], [ "&" ], [ "<<" ], [ ">>" ]].forEach(op => {
        env[op[0]] = new Function("lhs", "rhs", `return lhs ${op[1] || op[0]} rhs;`);
    });
    Object.assign(env, {
        append: (x, y, ...args) => x.concat(y).concat(...args),
        apply: (f, x) => f.apply(f, x),
        begin: (...args) => Array.isArray(args) ? args[args.length - 1] : undefined,
        car: (x) => x[0],
        cdr: (x) => x.slice(1),
        cons: (x, y) => [x].concat(y),
        display: (...args) => console.log(...args),
        "eq?": (x, y) => x === y,
        //"equal?" list contents equality D:
        length: (x) => x.length,
        list: (...args) => args,
        "list?": (x) => Array.isArray(x),
        map: (f, x) => x.map(f),
        not: (x) => x === false ? true : false,
        "null?": (x) => (Array.isArray(x) && x.length == 0) || (typeof x === "undefined") || (x === null),
        "number?": (x) => typeof x === "number",
        "procedure?": (x) => typeof x === "function",
        reverse: (x) => x.reverse(),
        "symbol?": (x) => typeof x === "string",
    });
    return env;
 };

 class Env {
    constructor(parms, args, outer) {
        if (typeof parms === "undefined") parms = []
        if (typeof args === "undefined") args = []
        parms.map((k, i) => this[k] = args[i]);
        this.outer = outer;
    }
    
    find(symbol) {
        if (typeof this[symbol] !== "undefined") {
            return this;
        }
        if (this.outer) {
            return this.outer.find(symbol);
        }
        throw new Error(`Symbol ${symbol} undefined`);
    }
 }

 var g = makeEnv();

 function makeProc(parms, body, env) {
    return function(...args) {
        return interp(body, new Env(parms, args, env));
    };
 }

 function interp(x, env) {
    env = env || g;
    if (typeof x === "string") { // symbol
        return env.find(x)[x];
    }
    else if (!Array.isArray(x)) { // constant literal
        return x;
    }
    else if (x[0] === "quote") { // (quote exp)
        let exp = x[1];
        return exp;
    }
    else if (x[0] === "if") { // (if test conseq alt)
        let test = x[1], conseq = x[2], alt = x[3];
        let exp = interp(test, env) ? conseq : alt;
        return interp(exp, env);
    }
    else if (x[0] === "define") { // (define symbol exp)
        let symbol = x[1], exp = x[2];
        env[symbol] = interp(exp, env);
    }
    else if (x[0] === "set!") { // (set! symbol exp)
        let symbol = x[1], exp = x[2];
        return (env.find(symbol)[symbol] = interp(exp, env));
    }
    else if (x[0] === "eval") { // custom shenanigans
        let exp = interp(x[1], env);
        return interp(exp, env);
    }
    else if (x[0] === "lambda") { // (lambda (symbol...) body)
        let parms = x[1], body = x[2];
        return makeProc(parms, body, env);
    }
    else {
        let proc = interp(x[0], env);
        let args = x.slice(1).map(exp => interp(exp, env));
        if (typeof proc !== "function") {
            throw new Error("Expected function, got " + (proc || "").toString());
        }
        return proc.apply(proc, args);
    }
 }

 function repl(source, out) {
    out.innerHTML += "<br>";
    out.innerHTML += "> " + source;

    let val;
    try {
        val = interp(load(source));
    }
    catch (e) {
        val = "ERROR: " + e.message;
    }
    if (typeof val !== "undefined") {
        out.innerHTML += "<br>";
        out.innerHTML += toLispString(val);
    }
 }

 function replSubmit(e) {
    e = e || window.event;
    if (e.keyCode == 13) {
        let elem = e.srcElement || e.target;
        repl(elem.value, document.getElementById("replOut"));
        elem.value = "";
        elem.scrollIntoView();
    }
 }

 </script>

 <div id="replOut">REPL:<br></div>
 <br>
 <input type="text" size="50" onkeydown="replSubmit()"/>  

 </body>
 </html>
	<html>
	<head>
	<title>Interpretoy REPL</title>
	</head>
	<body>

	<script>
	// based on lispy by Peter Norvig: http://norvig.com/lispy.html

	function load(source) {
	return parse(tokenize(source));
	}

	function tokenize(source) {
	return source.replaceAll("'", " ' ").replaceAll("(", " ( ").replaceAll(")", " ) ").replaceAll("\n", "").replaceAll("\r", "").replaceAll("\t", "").split(" ").filter(i => i);
	}

	function parse(tokens) {
	if (!tokens.length) {
	throw new Error("Unexpected EOF");
	}
	let token = tokens.shift();
	if (token === "(") {
	let l = [];
	while (tokens[0] !== ")") {
	l.push(parse(tokens));
	}
	tokens.shift();
	return l;
	}
	else if (token === "'") {
	let next = parse(tokens);
	return [ "quote", next ];
	}
	else if (token === ")") {
	throw new Error("Unexpected ')'");
	}
	else {
	return atom(token);
	}
	}

	function atom(token) {
	let num = token * 1;
	if (num \|\| num === 0) {
	return num;
	}
	return token;
	}

	function toLispString(l, s) {
	return [l].map(function join(v) {
	return Array.isArray(v) ? "(" + v.map(join).join(" ") + ")" : v;
	}).join(" ");
	}

	function makeEnv() {
	var env = new Env();
	Object.getOwnPropertyNames(Math).forEach(property => {
	if(typeof Math[property] === 'function') {
	env[property] = Math[property];
	}
	});
	[ ["+"], ["-"], ["*"], ["/"], ["<"], ["<="], [">"], [">="], [ "=", "===" ], [ "\|" ], [ "&" ], [ "<<" ], [ ">>" ]].forEach(op => {
	env[op[0]] = new Function("lhs", "rhs", `return lhs ${op[1] \|\| op[0]} rhs;`);
	});
	Object.assign(env, {
	append: (x, y, ...args) => x.concat(y).concat(...args),
	apply: (f, x) => f.apply(f, x),
	begin: (...args) => Array.isArray(args) ? args[args.length - 1] : undefined,
	car: (x) => x[0],
	cdr: (x) => x.slice(1),
	cons: (x, y) => [x].concat(y),
	display: (...args) => console.log(...args),
	"eq?": (x, y) => x === y,
	//"equal?" list contents equality D:
	length: (x) => x.length,
	list: (...args) => args,
	"list?": (x) => Array.isArray(x),
	map: (f, x) => x.map(f),
	not: (x) => x === false ? true : false,
	"null?": (x) => (Array.isArray(x) && x.length == 0) \|\| (typeof x === "undefined") \|\| (x === null),
	"number?": (x) => typeof x === "number",
	"procedure?": (x) => typeof x === "function",
	reverse: (x) => x.reverse(),
	"symbol?": (x) => typeof x === "string",
	});
	return env;
	};

	class Env {
	constructor(parms, args, outer) {
	if (typeof parms === "undefined") parms = []
	if (typeof args === "undefined") args = []
	parms.map((k, i) => this[k] = args[i]);
	this.outer = outer;
	}

	find(symbol) {
	if (typeof this[symbol] !== "undefined") {
	return this;
	}
	if (this.outer) {
	return this.outer.find(symbol);
	}
	throw new Error(`Symbol ${symbol} undefined`);
	}
	}

	var g = makeEnv();

	function makeProc(parms, body, env) {
	return function(...args) {
	return interp(body, new Env(parms, args, env));
	};
	}

	function interp(x, env) {
	env = env \|\| g;
	if (typeof x === "string") { // symbol
	return env.find(x)[x];
	}
	else if (!Array.isArray(x)) { // constant literal
	return x;
	}
	else if (x[0] === "quote") { // (quote exp)
	let exp = x[1];
	return exp;
	}
	else if (x[0] === "if") { // (if test conseq alt)
	let test = x[1], conseq = x[2], alt = x[3];
	let exp = interp(test, env) ? conseq : alt;
	return interp(exp, env);
	}
	else if (x[0] === "define") { // (define symbol exp)
	let symbol = x[1], exp = x[2];
	env[symbol] = interp(exp, env);
	}
	else if (x[0] === "set!") { // (set! symbol exp)
	let symbol = x[1], exp = x[2];
	return (env.find(symbol)[symbol] = interp(exp, env));
	}
	else if (x[0] === "eval") { // custom shenanigans
	let exp = interp(x[1], env);
	return interp(exp, env);
	}
	else if (x[0] === "lambda") { // (lambda (symbol...) body)
	let parms = x[1], body = x[2];
	return makeProc(parms, body, env);
	}
	else {
	let proc = interp(x[0], env);
	let args = x.slice(1).map(exp => interp(exp, env));
	if (typeof proc !== "function") {
	throw new Error("Expected function, got " + (proc \|\| "").toString());
	}
	return proc.apply(proc, args);
	}
	}

	function repl(source, out) {
	out.innerHTML += "<br>";
	out.innerHTML += "> " + source;

	let val;
	try {
	val = interp(load(source));
	}
	catch (e) {
	val = "ERROR: " + e.message;
	}
	if (typeof val !== "undefined") {
	out.innerHTML += "<br>";
	out.innerHTML += toLispString(val);
	}
	}

	function replSubmit(e) {
	e = e \|\| window.event;
	if (e.keyCode == 13) {
	let elem = e.srcElement \|\| e.target;
	repl(elem.value, document.getElementById("replOut"));
	elem.value = "";
	elem.scrollIntoView();
	}
	}

	</script>

	<div id="replOut">REPL:<br></div>
	<br>
	<input type="text" size="50" onkeydown="replSubmit()"/>

	</body>
	</html>