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Binding a variable in one function and using it in another is a powerful technique, but if used without restraint, it can make programs hard to understand. There are two clean ways to use this technique:
You should write comments to inform other programmers that they can see all uses of the variable before them, and to advise them not to add uses elsewhere.
case-fold-search
is
defined as “non-nil
means ignore case when searching”; various
search and replace functions refer to it directly or through their
subroutines, but do not bind or set it.
Then you can bind the variable in other programs, knowing reliably what the effect will be.
In either case, you should define the variable with defvar
. This
helps other people understand your program by telling them to look for
inter-function usage. It also avoids a warning from the byte compiler.
Choose the variable's name to avoid name conflicts—don't use short names
like x
.
Ce document a été généré par Eric Reinbold le 13 Octobre 2007 en utilisant texi2html 1.78.