def repl():
code = ''
while True:
code += input()
try:
parsed = parse(code)
except SyntaxError as e:
code += '\n'
continue
else:
result = scheme_eval(parsed, global_env)
print(result if result is not None else 'Unspecified value')
code = ''
def file_eval(filename):
with open(filename, 'r') as program_file:
code = program_file.read()
code = '(begin ' + code + ')'
parsed = parse(code)
scheme_eval(parsed, global_env)
