def let(args, env):
var_list = args.car
body = args.cdr
argnames = cons_list(i.car for i in var_list)
arg_values = cons_list(scheme_eval(i.cdr.car, env) for i in var_list)
l = create_lambda(Cell(argnames, body), env)
return l(arg_values)
def scheme_wrap(expr):
if isinstance(expr, bool):
return scheme_true if expr else scheme_false
elif isinstance(expr, Real):
return Number(expr)
elif isinstance(expr, str):
return String(expr)
elif isinstance(expr, Iterable):
return cons_list(map(scheme_wrap, expr))
else:
return expr
def __call__(self, arguments):
if type(self.argnames) is Symbol:
name_bind = {self.argnames: arguments}
elif Symbol('.') in self.argnames:
names_l = list(self.argnames)
args_l = list(arguments)
positionals = names_l.index(Symbol('.'))
name_bind = {s: v for s, v in zip(names_l[:positionals], args_l[:positionals])}
name_bind[names_l[positionals + 1]] = cons_list(args_l[positionals:])
else:
name_bind = {s: v for s, v in zip(self.argnames, arguments)}
call_env = Environment(self.parent_env, name_bind)
return scheme_eval(self.code, call_env)
def scheme_eval_list(lst, env):
return cons_list(map(lambda x: scheme_eval(x, env), iter(lst)))
def scheme_if(args, env):
return cond(cons_list([cons_list([args.car, args.cdr.car]),
cons_list([Symbol('else'), args.cdr.cdr.car])]), env)