#! /usr/bin/env python class Markov:    def __init__(self, histsize, choice):        self.histsize = histsize        self.choice = choice        self.trans = {}    def add(self, state, next):        if not self.trans.has_key(state):            self.trans[state] = [next]        else:            self.trans[state].append(next)    def put(self, seq):        n = self.histsize        add = self.add        add(None, seq[:0])        for i in range(len(seq)):            add(seq[max(0, i-n):i], seq[i:i+1])        add(seq[len(seq)-n:], None)    def get(self):        choice = self.choice        trans = self.trans        n = self.histsize        seq = choice(trans[None])        while 1:            subseq = seq[max(0, len(seq)-n):]            options = trans[subseq]            next = choice(options)            if not next: break            seq = seq + next        return seq def test():    import sys, string, random, getopt    args = sys.argv[1:]    try:        opts, args = getopt.getopt(args, '0123456789cdw')    except getopt.error:        print 'Usage: markov [-#] [-cddqw] [file] ...'        print 'Options:'        print '-#: 1-digit history size (default 2)'        print '-c: characters (default)'        print '-w: words'        print '-d: more debugging output'        print '-q: no debugging output'        print 'Input files (default stdin) are split in paragraphs'        print 'separated blank lines and each paragraph is split'        print 'in words by whitespace, then reconcatenated with'        print 'exactly one space separating words.'        print 'Output consists of paragraphs separated by blank'        print 'lines, where lines are no longer than 72 characters.'    histsize = 2    do_words = 0    debug = 1    for o, a in opts:        if '-0' <= o <= '-9': histsize = eval(o[1:])        if o == '-c': do_words = 0        if o == '-d': debug = debug + 1        if o == '-q': debug = 0        if o == '-w': do_words = 1    if not args: args = ['-']    m = Markov(histsize, random.choice)    try:        for filename in args:            if filename == '-':                f = sys.stdin                if f.isatty():                    print 'Sorry, need stdin from file'                    continue            else:                f = open(filename, 'r')            if debug: print 'processing', filename, '...'            text = f.read()            f.close()            paralist = string.splitfields(text, '\n\n')            for para in paralist:                if debug > 1: print 'feeding ...'                words = string.split(para)                if words:                    if do_words: data = tuple(words)                    else: data = string.joinfields(words, ' ')                    m.put(data)    except KeyboardInterrupt:        print 'Interrupted -- continue with data read so far'    if not m.trans:        print 'No valid input files'        return    if debug: print 'done.'    if debug > 1:        for key in m.trans.keys():            if key is None or len(key) < histsize:                print repr(key), m.trans[key]        if histsize == 0: print repr(''), m.trans['']        print    while 1:        data = m.get()        if do_words: words = data        else: words = string.split(data)        n = 0        limit = 72        for w in words:            if n + len(w) > limit:                print                n = 0            print w,            n = n + len(w) + 1        print        print def tuple(list):    if len(list) == 0: return ()    if len(list) == 1: return (list[0],)    i = len(list)/2    return tuple(list[:i]) + tuple(list[i:]) if __name__ == "__main__":    test()