我想使用 pexpect 从 python 中使用 maxima，每当 maxima 启动时，它都会打印一堆这种形式的东西：
$ maxima
Maxima 5.27.0 http://maxima.sourceforge.net
using Lisp SBCL 1.0.57-1.fc17
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1)
我想像这样启动pexpect：
import pexpect
cmd = 'maxima'
child = pexpect.spawn(cmd)
child.expect (' match all that stuff up to and including (%i1)')
child.sendline ('integrate(sin(x),x)')
chil.expect( match (%i2) i think ; see below sample session )
print child.before
如何将起始横幅与提示符 (%i1) 匹配？依此类推，随着会话的进行，最大值也会将 (%i1) 的值加一，
(%i1) integrate(sin(x),x);
(%o1) - cos(x)
(%i2) integrate(log(x),x);
(%o2) x log(x) - x
(%i3)
所以下一个期望是：
child.expect ('match (%i2)')
child.sendline ('integrate(log(x),x)')
child.expect( match (%i3) )
print child.before
我如何匹配（递增）整数？基本上我需要在打印（%o#）时匹配（%i#）。