elisp: Buffer-Local Variables
11.10 Buffer-Local Variables
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Global and local variable bindings are found in most programming
languages in one form or another. Emacs, however, also supports
additional, unusual kinds of variable binding, such as “buffer-local”
bindings, which apply only in one buffer. Having different values for a
variable in different buffers is an important customization method.
(Variables can also have bindings that are local to each terminal.
Multiple Terminals.)
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