1 --- step3_env -----------------------------------
2 import types, reader, printer, env
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)))
14 if not list?(ast): return eval_ast(ast, env)
15 if empty?(ast): return ast
17 'def!: return env.set(ast[1], EVAL(ast[2], env))
18 'let*: let_env = ...; return EVAL(ast[2], let_env)
19 _default_: f, args = eval_ast(ast, env)
22 PRINT(exp): return printer.pr_str(exp)
25 rep(str): return PRINT(EVAL(READ(str),repl_env))
27 repl_env.set('+, add_fn)
31 try: println(rep(readline("user> ")))
32 catch e: println("Error: ", e)
34 --- env module ----------------------------------
35 class Env (outer=null)
37 set(k,v): return data.set(k,v)
38 find(k): return data.has(k) ? this : (if outer ? find(outer) : null)
39 get(k): return data.find(k).get(k) OR raise "'" + k + "' not found"