On Thu, 12 May 2011 23:46:12 -0700, rusi wrote:
> Mathematics has existed for millenia. Hindu-arabic numerals (base-10
> numbers) have been known for about one millennium
> The boolean domain is only a 100 years old. Unsurprisingly it is not
> quite 'first-class' yet: See
> http://www.cs.utexas.edu/users/EWD/transcriptions/EWD10xx/EWD1070.html
> [Lifted from http://c2.com/cgi/wiki?EqualVsTrueFalse ]
Th money-quote as regards using arbitrary objects in truth tests:
[quote]
All this changed with the introduction of the two-element
boolean domain {true, false} which provides the vocabulary
needed to assign values to boolean expressions: 3<4 is a
way for writing true, 3>4 is a way for writing false,
whereas the value of x>0 depends on the value of x ...
[end quote]
In Python, [1, 2, 3] is another way of writing true, and [] is another
way of writing false. Similarly with any other arbitrary objects. The
only things that bools True and False are good for are:
* giving functions a canonical way of spelling true/false when they want
to emit a Boolean value;
* giving documentation writers a canonical way of spelling true/false
when they want to discuss passing a Boolean value.
Other than those conveniences, there's nothing you can do with True and
False in Python that you can't do with any other set of objects.
--
Steven
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