OK. Here it is.
I want to make a monitor tool for linux. It runs for a long time, and give
out a certain process's io stat per second. The way I get io stat is to read
from /proc/pid/io. But the data in this file is a total, I need to read it
first, then next second, read it again, and shows the difference, and go on.
So, what is your idea?
-----邮件原件-----
发件人: David Roundy [mailto:daveroundy@gmail.com]
发送时间: 2008年6月17日 1:17
收件人: Magicloud Magiclouds
抄送: haskell-cafe@haskell.org
主题: Re: [Haskell-cafe] How to do this in FP way?
2008/6/15 Magicloud Magiclouds
Hello, I am getting familiar with FP now, and I have a "program design" kind of question. Say I have something like this in C: static int old; int diff (int now) { /* this would be called once a second */ int ret = now - old; old = now; return ret; } Because there is no "variable" in Haskell. So how to do this in a FP way?
A better question would be to think about what you are trying to accomplish, and then ask how to achieve that through functional programming. David