1 --- step5_tco -----------------------------------
2 import types, reader, printer, env, core
4 READ(str): return reader.read_str(str)
8 symbol: return env.get(ast)
9 list,vector: return ast.map((x) -> EVAL(x,env))
10 hash: return ast.map((k,v) -> list(k, EVAL(v,env)))
15 if not list?(ast): return eval_ast(ast, env)
16 if empty?(ast): return ast
18 'def!: return env.set(ast[1], EVAL(ast[2], env))
19 'let*: env = ...; ast = ast[2] // TCO
20 'do: ast = eval_ast(ast[1..-1], env)[-1] // TCO
21 'if: EVAL(ast[1], env) ? ast = ast[2] : ast = ast[3] // TCO
22 'fn*: return new MalFunc(...)
23 _default_: f, args = eval_ast(ast, env)
24 if malfunc?(f): ast = f.fn; env = ... // TCO
25 else: return apply(f, args)
27 PRINT(exp): return printer.pr_str(exp)
30 rep(str): return PRINT(EVAL(READ(str),repl_env))
32 ;; core.EXT: defined using Racket
33 core.ns.map((k,v) -> (repl_env.set(k, v)))
35 ;; core.mal: defined using the language itself
36 rep("(def! not (fn* (a) (if a false true)))")
39 try: println(rep(readline("user> ")))
40 catch e: println("Error: ", e)
42 --- env module ----------------------------------
43 class Env (outer=null,binds=[],exprs=[])
45 foreach b, i in binds:
46 if binds[i] == '&: data[binds[i+1]] = exprs.drop(i); break
47 else: data[binds[i]] = exprs[i]
48 set(k,v): return data.set(k,v)
49 find(k): return data.has(k) ? this : (if outer ? find(outer) : null)
50 get(k): return data.find(k).get(k) OR raise "'" + k + "' not found"
52 --- core module ---------------------------------
55 'pr-str: (a) -> a.map(|s| pr_str(e,true)).join(" ")),
56 'str: (a) -> a.map(|s| pr_str(e,false)).join("")),
57 'prn: (a) -> println(a.map(|s| pr_str(e,true)).join(" ")),
58 'println: (a) -> println(a.map(|s| pr_str(e,false)).join(" ")),