[Python-Dev] RE: PEP 285: Adding a bool type (original) (raw)

Andrew Koenig ark@research.att.com
30 Mar 2002 10:52:47 -0500

Guido> You've been staring at standards too much, haven't you? The Guido> difference between MUST and SHOULD isn't as clear-cut as most Guido> standards people use them.

In the ISO standards world, ``must'' doesn't mean what you probably think it does:

    should:    encouraged, but not required
    shall:     required
    must:      it is impossible for things to be otherwise

So, for example, one can imagine describing a function with a Boolean parameter named x by saying something like:

    If x is true, the result shall be foo.
    Otherwise, x must be false, and the result shall be bar.

-- Andrew Koenig, ark@research.att.com, http://www.research.att.com/info/ark