括号，658字节
((()()())(()(((()))))((()()((())))))((()()())(()(((())))()()())((())()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()))((()()())(()(((())))())((()())((()(((())))()()))((()()()())((()(())(()))(()(((())))()())(()((()))))(()((())))((()((()))())((()(())(())())((()(()))(()(((())))()()())((()(()()))((())()()()()()()()()()()()()()()()()()()()()()()()()())((()(()()))((()(()())())((()((()))(()))(()(((())))()())))(()(((())))()()())))))((()(((())))())((()((()))()())(()(((())))()())))))))((()(())(()))((()()()(()))((()()()()())(()(((()))))))((()(((())))())((()()()()())(()(((())))))))
使用此脚本的修改后的版本，现在仅适用于所有不带空格的大写字母，以便支持从stdin读取：
#!/usr/bin/env python
from collections import defaultdict
from itertools import izip
import copy
import operator
import os
import sys
# map from paren strings to english names
# for the predefined symbols (lambda, etc)
to_english = defaultdict(lambda:None,\
{'()': 'lambda',
'()()': 'define',
'(())': 'plus',
'(()())': 'minus',
'()(())': 'mult',
'(())()': 'div',
'()()()': 'if',
'((()))': 'empty',
'()()()()': 'charsof',
'()()(())': 'reverse',
'()(())()': 'LE',
'()(()())': 'not',
'(()())()': 'intofchar',
'()((()))': 'readline',
'((()))()': 'cons',
'(())(())': 'equal',
'((()))(())': 'car',
'((()))()()': 'cdr',
'(())(())()': 'char',
'(())()(())': 'string'})
# map from english to parenthetic
to_scheme = defaultdict(lambda:None)
for k,v in to_english.iteritems():
to_scheme[v] = k
def Error(errorString = 'unmatched parens', debug_mode = True):
if debug_mode:
print "Error: " + errorString
sys.exit()
else:
raise Exception('paren mismatch')
def bracketsMatch(chars):
"""Returns False if any parentheses in `chars` are not matched
properly. Returns True otherwise.
"""
level = 0
for p in chars:
if p == '(':
level += 1
elif p == ')':
level -= 1
if level < 0:
return False
return level == 0
def get_exprs(chars):
"""Returns a list of character sequences such that for each sequence,
the first and last parenthesis match.
For example, "(())()()" would be split into ["(())", "()", "()"]
"""
level = 0
current = []
for p in chars:
if p == '(' or p == ')':
current.append(p)
if p == '(':
level += 1
elif p == ')':
level -= 1
if level == 0:
yield current
current = []
## built-in functions ##
def builtin_accumulate(init, accumulate, environment, params):
"""Helper function that handles common logic for builtin functions.
Given an initial value, and a two-parameter function, the environment, and
a list of params to reduce, this function will reduce [init] + params using
the accumulate function and finally returns the resulting value.
"""
result = init
for param in params:
value = interpret(param, environment)
try: result = accumulate(result, value)
except: Error(str(value) + ' is not the correct type')
return result
def builtin_plus(environment, params):
if len(params) >= 1:
return builtin_accumulate(interpret(params[0], environment), operator.add, environment, params[1:])
else:
return 0.0
def builtin_minus(environment, params):
if len(params) == 0:
Error('subtraction requires at least 1 param')
return builtin_accumulate(interpret(params[0], environment), operator.sub, environment, params[1:])
def builtin_mult(environment, params):
return builtin_accumulate(1.0, operator.mul, environment, params)
def builtin_div(environment, params):
if len(params) == 0:
Error('division requires at least 1 param')
return builtin_accumulate(interpret(params[0], environment), operator.div, environment, params[1:])
def builtin_LE(environment, params):
return interpret(params[0], environment) <= interpret(params[1], environment)
def builtin_lambda(environment, params):
bodies = [body for body in params[1:]]
params = params[0][1]
if len(bodies) == 0:
Error("a function had no body")
for kind, name in params:
if kind != 'symbol':
Error('lambda must have only symbols as arguments')
def ret(old_environment, arguments):
#print bodies
try:
# create new environment based on args
environment = copy.copy(old_environment)
for param, arg in izip(params, arguments):
environment[param[1]] = interpret(arg, old_environment)
# evaluate the function bodies using the new environment
return interpret_trees(bodies, environment, False)
except:
Error("Error evaluating a function")
return ret
def builtin_equal(environment, params):
for param1, param2 in izip(params[:-1], params[1:]):
if interpret(param1, environment) != interpret(param2, environment):
return False
return True
def builtin_if(environment, params):
if len(params) != 3:
Error("'if' takes in exactly 3 params")
if interpret(params[0], environment):
return interpret(params[1], environment)
return interpret(params[2], environment)
def builtin_not(environment, params):
return False if interpret(params[0], environment) else True
def builtin_cons(environment, params):
return (interpret(params[0], environment), interpret(params[1], environment))
def builtin_car(environment, params):
result = interpret(params[0], environment)
if not isinstance(result, tuple):
Error("car must only be called on tuples")
return result[0]
def builtin_cdr(environment, params):
result = interpret(params[0], environment)
if not isinstance(result, tuple):
Error("cdr must only be called on tuples")
return result[1]
def builtin_char(environment, params):
result = interpret(params[0], environment)
if result != int(result):
Error("char must only be called on integers")
return chr(int(result))
def builtin_intofchar(environment, params):
result = interpret(params[0], environment)
result = ord(result)
return result
def builtin_string(environment, params):
result = ''
cur = interpret(params[0], environment)
while cur != ():
if not isinstance(cur, tuple) or not isinstance(cur[1], tuple):
Error("string only works on linked lists")
result += cur[0]
cur = cur[1]
return result
def unmakelinked(llist):
result = ()
while llist != ():
if not isinstance(llist, tuple) or not isinstance(llist[1], tuple):
Error("only works on linked lists")
result += (llist[0],)
llist = llist[1]
return result
def makelinked(tup):
result = ()
while tup != ():
result = (tup[-1],result)
tup = tup[:-1]
return result
def builtin_reverse(environment, params):
result = interpret(params[0], environment)
result = makelinked(unmakelinked(result)[::-1])
return result
def builtin_charsof(environment, params):
result = interpret(params[0], environment)
result = makelinked(tuple(result))
return result
def builtin_readline(environment, params):
result = raw_input()
return result
# define the default (top-level) scope
default_environment = \
{to_scheme['plus']: builtin_plus,
to_scheme['minus']: builtin_minus,
to_scheme['mult']: builtin_mult,
to_scheme['div']: builtin_div,
to_scheme['lambda']: builtin_lambda,
to_scheme['if']: builtin_if,
to_scheme['equal']: builtin_equal,
to_scheme['LE']: builtin_LE,
to_scheme['not']: builtin_not,
to_scheme['empty']: (),
to_scheme['car']: builtin_car,
to_scheme['cdr']: builtin_cdr,
to_scheme['cons']: builtin_cons,
to_scheme['char']: builtin_char,
to_scheme['string']: builtin_string,
to_scheme['readline']: builtin_readline,
to_scheme['charsof']: builtin_charsof,
to_scheme['reverse']: builtin_reverse,
to_scheme['intofchar']: builtin_intofchar}
# parse the tokens into an AST
def parse(tokens):
"""Accepts a list of parentheses and returns a list of ASTs.
Each AST is a pair (type, value).
If type is 'symbol', value will be the paren sequence corresponding
to the symbol.
If type is 'int', value will be a float that is equal to an int.
If type is expr, value will be a list of ASTs.
"""
# check for errors
if not bracketsMatch(tokens):
Error('paren mismatch')
# to return - a list of exprs
exprs = []
for expr in get_exprs(tokens):
# check for errors
if len(expr) < 2:
Error('too few tokens in: ' + ''.join(expr))
elif expr[0] != '(' or expr[-1] != ')':
Error('expression found without () as wrapper')
# pop off starting and ending ()s
expr = expr[1:-1]
# symbol
if expr[:2] == ['(', ')'] and len(expr) > 2:
exprs.append(('symbol', ''.join(expr[2:])))
# integer
elif expr[:4] == ['(', '(', ')', ')'] and len(expr) >= 4:
exprs.append(('num', expr[4:].count('(')))
# expr
else:
exprs.append(('expr', parse(expr)))
return exprs
def interpret(tree, environment):
"""Interpret a single tree (may not be a define) and return the result"""
kind, value = tree
if kind == 'num':
return float(value)
elif kind == 'symbol':
if value in environment:
return environment[value]
else:
Error('Unresolved symbol - ' + value)
elif kind == 'expr':
function = interpret(value[0], environment)
if not hasattr(function, '__call__'):
Error('Symbol "'+value[0]+'" is not a function.')
return function(environment, value[1:])
else:
Error("Unknown tree kind")
def interpret_trees(trees, environment, doprint = True):
"""Interpret a sequence of trees (may contain defines)
and output the result.
The trees passed in should be ASTs as returned by parse().
If doprint is true, the post-interpretation value of each tree is printed.
"""
environment = copy.copy(environment)
# hoist define statements (note: trees.sort is stable)
#trees.sort(key = lambda x: 0 if x[0] == 'expr' and x[1][0][1] == to_scheme['define'] else 1)
ret = None
for tree in trees:
if tree[0] == 'expr' and tree[1][0][0] == 'symbol' and tree[1][0][1] == to_scheme['define']:
try:
symbol = tree[1][1]
if symbol[0] != 'symbol':
Error('first argument to define must be a symbol')
symbol = symbol[1]
value = tree[1][2]
environment[symbol] = interpret(value, environment)
except:
Error('error evaluating define statement')
else:
ret = interpret(tree, environment)
if doprint:
print ret,
return ret
# read in the code ignoring all characters but '(' and ')'
f = open(sys.argv[1],'r')
code = []
for line in f.readlines():
code += [c for c in line if c in '()']
# parse and interpret the code. print 'Parenthesis Mismatch'
# if an error occured.
#try:
syntax_trees = parse(code)
interpret_trees(syntax_trees, default_environment)
#except:
# print 'Parenthesis Mismatch'
说明
(
define
(() ()())
input [[[[]]]]
(() (((()))))
exec readline
( (() ()((()))) )
)
(
define
(() ()())
value of 'A' [[[[]]]] [][][]
(() (((())))()()())
65
((()) ()()()()()()()()()()
()()()()()()()()()()
()()()()()()()()()()
()()()()()()()()()()
()()()()()()()()()()
()()()()()()()()()()
()()()()())
)
(
define
(() ()())
atbash [[[[]]]] []
(() (((())))())
(
lambda
(() ())
(
list [[[[]]]] [][]
(() (((())))()())
)
(
if
(() ()()())
(
equal
(() (())(()))
list
(() (((())))()())
empty
(() ((())))
)
then return empty
(() ((())))
else
(
cons
(() ((()))())
(
char
(() (())(())())
(
plus
(() (()))
value of 'A' 65
(() (((())))()()())
(
minus
(() (()()))
25
((()) ()()()()()()()()()()
()()()()()()()()()()
()()()()())
(
minus
(() (()()))
(
intofchar
(() (()())())
(
car
(() ((()))(()))
list
(() (((())))()())
)
)
value of 'A' 65
(() (((())))()()())
)
)
)
)
(
atbash
(() (((())))())
(
cdr
(() ((()))()())
list
(() (((())))()())
)
)
)
)
)
)
(
equals
(() (())(()))
(
reverse
(() ()()(()))
(
charsof
(() ()()()())
input
(() (((()))))
)
)
(
atbash
(() (((())))())
(
charsof
(() ()()()())
input
(() (((()))))
)
)
)