mirror of
https://github.com/kanaka/mal.git
synced 2024-11-11 00:52:44 +03:00
321 lines
11 KiB
TypeScript
321 lines
11 KiB
TypeScript
import { readline } from "./node_readline";
|
|
|
|
import { Node, MalType, MalString, MalNil, MalList, MalVector, MalHashMap, MalSymbol, MalFunction, isAST, isSeq } from "./types";
|
|
import { Env } from "./env";
|
|
import * as core from "./core";
|
|
import { readStr } from "./reader";
|
|
import { prStr } from "./printer";
|
|
|
|
// READ
|
|
function read(str: string): MalType {
|
|
return readStr(str);
|
|
}
|
|
|
|
function quasiquote(ast: MalType): MalType {
|
|
if (!isPair(ast)) {
|
|
return new MalList([MalSymbol.get("quote"), ast]);
|
|
}
|
|
if (!isSeq(ast)) {
|
|
throw new Error(`unexpected token type: ${ast.type}, expected: list or vector`);
|
|
}
|
|
const [arg1, arg2] = ast.list;
|
|
if (arg1.type === Node.Symbol && arg1.v === "unquote") {
|
|
return arg2;
|
|
}
|
|
if (isPair(arg1)) {
|
|
if (!isSeq(arg1)) {
|
|
throw new Error(`unexpected token type: ${arg1.type}, expected: list or vector`);
|
|
}
|
|
const [arg11, arg12] = arg1.list;
|
|
if (arg11.type === Node.Symbol && arg11.v === "splice-unquote") {
|
|
return new MalList([
|
|
MalSymbol.get("concat"),
|
|
arg12,
|
|
quasiquote(new MalList(ast.list.slice(1))),
|
|
]);
|
|
}
|
|
}
|
|
|
|
return new MalList([
|
|
MalSymbol.get("cons"),
|
|
quasiquote(arg1),
|
|
quasiquote(new MalList(ast.list.slice(1))),
|
|
]);
|
|
|
|
function isPair(ast: MalType) {
|
|
if (!isSeq(ast)) {
|
|
return false;
|
|
}
|
|
|
|
return 0 < ast.list.length;
|
|
}
|
|
}
|
|
|
|
function isMacro(ast: MalType, env: Env): boolean {
|
|
if (!isSeq(ast)) {
|
|
return false;
|
|
}
|
|
const s = ast.list[0];
|
|
if (s.type !== Node.Symbol) {
|
|
return false;
|
|
}
|
|
const foundEnv = env.find(s);
|
|
if (!foundEnv) {
|
|
return false;
|
|
}
|
|
|
|
const f = foundEnv.get(s);
|
|
if (f.type !== Node.Function) {
|
|
return false;
|
|
}
|
|
|
|
return f.isMacro;
|
|
}
|
|
|
|
function macroexpand(ast: MalType, env: Env): MalType {
|
|
while (isMacro(ast, env)) {
|
|
if (!isSeq(ast)) {
|
|
throw new Error(`unexpected token type: ${ast.type}, expected: list or vector`);
|
|
}
|
|
const s = ast.list[0];
|
|
if (s.type !== Node.Symbol) {
|
|
throw new Error(`unexpected token type: ${s.type}, expected: symbol`);
|
|
}
|
|
const f = env.get(s);
|
|
if (f.type !== Node.Function) {
|
|
throw new Error(`unexpected token type: ${f.type}, expected: function`);
|
|
}
|
|
ast = f.func(...ast.list.slice(1));
|
|
}
|
|
|
|
return ast;
|
|
}
|
|
|
|
function evalAST(ast: MalType, env: Env): MalType {
|
|
switch (ast.type) {
|
|
case Node.Symbol:
|
|
const f = env.get(ast);
|
|
if (!f) {
|
|
throw new Error(`unknown symbol: ${ast.v}`);
|
|
}
|
|
return f;
|
|
case Node.List:
|
|
return new MalList(ast.list.map(ast => evalMal(ast, env)));
|
|
case Node.Vector:
|
|
return new MalVector(ast.list.map(ast => evalMal(ast, env)));
|
|
case Node.HashMap:
|
|
const list: MalType[] = [];
|
|
for (const [key, value] of ast.entries()) {
|
|
list.push(key);
|
|
list.push(evalMal(value, env));
|
|
}
|
|
return new MalHashMap(list);
|
|
default:
|
|
return ast;
|
|
}
|
|
}
|
|
|
|
// EVAL
|
|
function evalMal(ast: MalType, env: Env): MalType {
|
|
loop: while (true) {
|
|
if (ast.type !== Node.List) {
|
|
return evalAST(ast, env);
|
|
}
|
|
|
|
ast = macroexpand(ast, env);
|
|
if (!isSeq(ast)) {
|
|
return evalAST(ast, env);
|
|
}
|
|
|
|
if (ast.list.length === 0) {
|
|
return ast;
|
|
}
|
|
const first = ast.list[0];
|
|
switch (first.type) {
|
|
case Node.Symbol:
|
|
switch (first.v) {
|
|
case "def!": {
|
|
const [, key, value] = ast.list;
|
|
if (key.type !== Node.Symbol) {
|
|
throw new Error(`unexpected token type: ${key.type}, expected: symbol`);
|
|
}
|
|
if (!value) {
|
|
throw new Error(`unexpected syntax`);
|
|
}
|
|
return env.set(key, evalMal(value, env))
|
|
}
|
|
case "let*": {
|
|
env = new Env(env);
|
|
const pairs = ast.list[1];
|
|
if (!isSeq(pairs)) {
|
|
throw new Error(`unexpected token type: ${pairs.type}, expected: list or vector`);
|
|
}
|
|
for (let i = 0; i < pairs.list.length; i += 2) {
|
|
const key = pairs.list[i];
|
|
const value = pairs.list[i + 1];
|
|
if (key.type !== Node.Symbol) {
|
|
throw new Error(`unexpected token type: ${key.type}, expected: symbol`);
|
|
}
|
|
if (!key || !value) {
|
|
throw new Error(`unexpected syntax`);
|
|
}
|
|
|
|
env.set(key, evalMal(value, env));
|
|
}
|
|
ast = ast.list[2];
|
|
continue loop;
|
|
}
|
|
case "quote": {
|
|
return ast.list[1];
|
|
}
|
|
case "quasiquote": {
|
|
ast = quasiquote(ast.list[1]);
|
|
continue loop;
|
|
}
|
|
case "defmacro!": {
|
|
const [, key, value] = ast.list;
|
|
if (key.type !== Node.Symbol) {
|
|
throw new Error(`unexpected token type: ${key.type}, expected: symbol`);
|
|
}
|
|
if (!value) {
|
|
throw new Error(`unexpected syntax`);
|
|
}
|
|
const f = evalMal(value, env);
|
|
if (f.type !== Node.Function) {
|
|
throw new Error(`unexpected token type: ${f.type}, expected: function`);
|
|
}
|
|
f.isMacro = true;
|
|
return env.set(key, f);
|
|
}
|
|
case "macroexpand": {
|
|
return macroexpand(ast.list[1], env);
|
|
}
|
|
case "try*": {
|
|
try {
|
|
return evalMal(ast.list[1], env);
|
|
} catch (e) {
|
|
const catchBody = ast.list[2];
|
|
if (!isSeq(catchBody)) {
|
|
throw new Error(`unexpected return type: ${catchBody.type}, expected: list or vector`);
|
|
}
|
|
const catchSymbol = catchBody.list[0];
|
|
if (catchSymbol.type === Node.Symbol && catchSymbol.v === "catch*") {
|
|
const errorSymbol = catchBody.list[1];
|
|
if (errorSymbol.type !== Node.Symbol) {
|
|
throw new Error(`unexpected return type: ${errorSymbol.type}, expected: symbol`);
|
|
}
|
|
if (!isAST(e)) {
|
|
e = new MalString((e as Error).message);
|
|
}
|
|
return evalMal(catchBody.list[2], new Env(env, [errorSymbol], [e]));
|
|
}
|
|
throw e;
|
|
}
|
|
}
|
|
case "do": {
|
|
const list = ast.list.slice(1, -1);
|
|
evalAST(new MalList(list), env);
|
|
ast = ast.list[ast.list.length - 1];
|
|
continue loop;
|
|
}
|
|
case "if": {
|
|
const [, cond, thenExpr, elseExrp] = ast.list;
|
|
const ret = evalMal(cond, env);
|
|
let b = true;
|
|
if (ret.type === Node.Boolean && !ret.v) {
|
|
b = false;
|
|
} else if (ret.type === Node.Nil) {
|
|
b = false;
|
|
}
|
|
if (b) {
|
|
ast = thenExpr;
|
|
} else if (elseExrp) {
|
|
ast = elseExrp;
|
|
} else {
|
|
ast = MalNil.instance;
|
|
}
|
|
continue loop;
|
|
}
|
|
case "fn*": {
|
|
const [, params, bodyAst] = ast.list;
|
|
if (!isSeq(params)) {
|
|
throw new Error(`unexpected return type: ${params.type}, expected: list or vector`);
|
|
}
|
|
const symbols = params.list.map(param => {
|
|
if (param.type !== Node.Symbol) {
|
|
throw new Error(`unexpected return type: ${param.type}, expected: symbol`);
|
|
}
|
|
return param;
|
|
});
|
|
return MalFunction.fromLisp(evalMal, env, symbols, bodyAst);
|
|
}
|
|
}
|
|
}
|
|
const result = evalAST(ast, env);
|
|
if (!isSeq(result)) {
|
|
throw new Error(`unexpected return type: ${result.type}, expected: list or vector`);
|
|
}
|
|
const [f, ...args] = result.list;
|
|
if (f.type !== Node.Function) {
|
|
throw new Error(`unexpected token: ${f.type}, expected: function`);
|
|
}
|
|
if (f.ast) {
|
|
ast = f.ast;
|
|
env = f.newEnv(args);
|
|
continue loop;
|
|
}
|
|
|
|
return f.func(...args);
|
|
}
|
|
}
|
|
|
|
// PRINT
|
|
function print(exp: MalType): string {
|
|
return prStr(exp);
|
|
}
|
|
|
|
const replEnv = new Env();
|
|
function rep(str: string): string {
|
|
return print(evalMal(read(str), replEnv));
|
|
}
|
|
|
|
// core.EXT: defined using Racket
|
|
core.ns.forEach((value, key) => {
|
|
replEnv.set(key, value);
|
|
});
|
|
replEnv.set(MalSymbol.get("eval"), MalFunction.fromBootstrap(ast => {
|
|
if (!ast) {
|
|
throw new Error(`undefined argument`);
|
|
}
|
|
return evalMal(ast, replEnv);
|
|
}));
|
|
replEnv.set(MalSymbol.get("*ARGV*"), new MalList([]));
|
|
|
|
// core.mal: defined using the language itself
|
|
rep("(def! not (fn* (a) (if a false true)))");
|
|
rep(`(def! load-file (fn* (f) (eval (read-string (str "(do " (slurp f) ")")))))`);
|
|
rep(`(defmacro! cond (fn* (& xs) (if (> (count xs) 0) (list 'if (first xs) (if (> (count xs) 1) (nth xs 1) (throw "odd number of forms to cond")) (cons 'cond (rest (rest xs)))))))`);
|
|
rep('(defmacro! or (fn* (& xs) (if (empty? xs) nil (if (= 1 (count xs)) (first xs) `(let* (or_FIXME ~(first xs)) (if or_FIXME or_FIXME (or ~@(rest xs))))))))');
|
|
|
|
if (typeof process !== "undefined" && 2 < process.argv.length) {
|
|
replEnv.set(MalSymbol.get("*ARGV*"), new MalList(process.argv.slice(3).map(s => new MalString(s))));
|
|
rep(`(load-file "${process.argv[2]}")`);
|
|
process.exit(0);
|
|
}
|
|
|
|
while (true) {
|
|
const line = readline("user> ");
|
|
if (line == null) {
|
|
break;
|
|
}
|
|
if (line === "") {
|
|
continue;
|
|
}
|
|
try {
|
|
console.log(rep(line));
|
|
} catch (e) {
|
|
const err: Error = e;
|
|
console.error(err.message);
|
|
}
|
|
}
|