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Diffstat (limited to 'Doc/ref/ref3.tex')
| -rw-r--r-- | Doc/ref/ref3.tex | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/Doc/ref/ref3.tex b/Doc/ref/ref3.tex index d355b691c8..2056a6c78d 100644 --- a/Doc/ref/ref3.tex +++ b/Doc/ref/ref3.tex @@ -162,7 +162,7 @@ complex numbers: These represent elements from the mathematical set of whole numbers. \obindex{integer} -There are two types of integers: +There are three types of integers: \begin{description} @@ -187,6 +187,17 @@ represented in a variant of 2's complement which gives the illusion of an infinite string of sign bits extending to the left. \obindex{long integer} +\item[Booleans] +These represent the truth values False and True. The two objects +representing the values False and True are the only Boolean objects. +The Boolean type is a subtype of plain integers, and Boolean values +behave like the values 0 and 1, respectively, in almost all contexts, +the exception being that when converted to a string, the strings +\code{"False"} or \code{"True"} are returned, respectively. +\obindex{Boolean} +\ttindex{False} +\ttindex{True} + \end{description} % Integers The rules for integer representation are intended to give the most @@ -222,6 +233,7 @@ and \code{z.imag}. \end{description} % Numbers + \item[Sequences] These represent finite ordered sets indexed by non-negative numbers. The built-in function \function{len()}\bifuncindex{len} returns the @@ -1074,8 +1086,10 @@ wrong hash bucket). \end{methoddesc} \begin{methoddesc}[object]{__nonzero__}{self} -Called to implement truth value testing; should return \code{0} or -\code{1}. When this method is not defined, \method{__len__()} is +Called to implement truth value testing, and the built-in operation +\code{bool()}; should return \code{False} or \code{True}, or their +integer equivalents \code{0} or \code{1}. +When this method is not defined, \method{__len__()} is called, if it is defined (see below). If a class defines neither \method{__len__()} nor \method{__nonzero__()}, all its instances are considered true. |