import rdstdin, tables, sequtils, os, types, reader, printer, env, core proc read(str: string): MalType = str.read_str proc is_pair(x: MalType): bool = x.kind in {List, Vector} and x.list.len > 0 proc quasiquote(ast: MalType): MalType = if not ast.is_pair: return list(symbol "quote", ast) elif ast.list[0] == symbol "unquote": return ast.list[1] elif ast.list[0].is_pair and ast.list[0].list[0] == symbol "splice-unquote": return list(symbol "concat", ast.list[0].list[1], quasiquote(list ast.list[1 .. -1])) else: return list(symbol "cons", quasiquote(ast.list[0]), quasiquote(list(ast.list[1 .. -1]))) proc is_macro_call(ast: MalType, env: Env): bool = ast.kind == List and ast.list.len > 0 and ast.list[0].kind == Symbol and env.find(ast.list[0].str) != nil and env.get(ast.list[0].str).macro_q proc macroexpand(ast: MalType, env: Env): MalType = result = ast while result.is_macro_call(env): let mac = env.get(result.list[0].str) result = mac.malfun.fn(result.list[1 .. -1]).macroexpand(env) proc eval(ast: MalType, env: Env): MalType proc eval_ast(ast: MalType, env: var Env): MalType = case ast.kind of Symbol: result = env.get(ast.str) of List: result = list ast.list.mapIt(MalType, it.eval(env)) of Vector: result = vector ast.list.mapIt(MalType, it.eval(env)) of HashMap: result = hash_map() for k, v in ast.hash_map.pairs: result.hash_map[k] = v.eval(env) else: result = ast proc eval(ast: MalType, env: Env): MalType = var ast = ast var env = env template defaultApply = let el = ast.eval_ast(env) let f = el.list[0] case f.kind of MalFun: ast = f.malfun.ast env = initEnv(f.malfun.env, f.malfun.params, list(el.list[1 .. -1])) else: return f.fun(el.list[1 .. -1]) while true: if ast.kind != List: return ast.eval_ast(env) ast = ast.macroexpand(env) if ast.kind != List: return ast if ast.list.len == 0: return ast let a0 = ast.list[0] case a0.kind of Symbol: case a0.str of "def!": let a1 = ast.list[1] a2 = ast.list[2] res = a2.eval(env) return env.set(a1.str, res) of "let*": let a1 = ast.list[1] a2 = ast.list[2] var let_env = Env(env) case a1.kind of List, Vector: for i in countup(0, a1.list.high, 2): let_env.set(a1.list[i].str, a1.list[i+1].eval(let_env)) else: raise newException(ValueError, "Illegal kind in let*") ast = a2 env = let_env # Continue loop (TCO) of "quote": return ast.list[1] of "quasiquote": ast = ast.list[1].quasiquote # Continue loop (TCO) of "defmacro!": var fun = ast.list[2].eval(env) fun.malfun.is_macro = true return env.set(ast.list[1].str, fun) of "macroexpand": return ast.list[1].macroexpand(env) of "try*": let a1 = ast.list[1] a2 = ast.list[2] if a2.list[0].str == "catch*": try: return a1.eval(env) except MalError: let exc = (ref MalError) getCurrentException() var catchEnv = initEnv(env, list a2.list[1], exc.t) return a2.list[2].eval(catchEnv) except: let exc = getCurrentExceptionMsg() var catchEnv = initEnv(env, list a2.list[1], list str(exc)) return a2.list[2].eval(catchEnv) else: return a1.eval(env) of "do": let last = ast.list.high let el = (list ast.list[1 .. 3: ast = ast.list[3] else: ast = nilObj else: ast = a2 of "fn*": let a1 = ast.list[1] a2 = ast.list[2] var env2 = env let fn = proc(a: varargs[MalType]): MalType = var newEnv = initEnv(env2, a1, list(a)) a2.eval(newEnv) return malfun(fn, a2, a1, env) else: defaultApply() else: defaultApply() proc print(exp: MalType): string = exp.pr_str var repl_env = initEnv() for k, v in ns.items: repl_env.set(k, v) repl_env.set("eval", fun(proc(xs: varargs[MalType]): MalType = eval(xs[0], repl_env))) var ps = commandLineParams() repl_env.set("*ARGV*", list((if paramCount() > 1: ps[1..ps.high] else: @[]).map(str))) # core.nim: defined using nim proc rep(str: string): string {.discardable.} = str.read.eval(repl_env).print # core.mal: defined using mal 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))))))))" rep "(def! *host-language* \"nim\")" if paramCount() >= 1: rep "(load-file \"" & paramStr(1) & "\")" quit() rep "(println (str \"Mal [\" *host-language* \"]\"))" while true: try: let line = readLineFromStdin("user> ") echo line.rep except Blank: discard except: echo getCurrentExceptionMsg() echo getCurrentException().getStackTrace()