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authorKim F. Storm <storm@cua.dk>2002-05-13 19:04:27 +0000
committerKim F. Storm <storm@cua.dk>2002-05-13 19:04:27 +0000
commitc152cd2a2015be5659746aea7e713499c65edbee (patch)
tree608b770ca1974da7da5846a567c6a1c39dfe8ec4 /lispref
parent4e792dbd39e6229446931c11803e3a40952236c3 (diff)
downloademacs-c152cd2a2015be5659746aea7e713499c65edbee.tar.gz
(Intro to Buffer-Local): Updated warning and
example relating to changing buffer inside let.
Diffstat (limited to 'lispref')
-rw-r--r--lispref/variables.texi21
1 files changed, 11 insertions, 10 deletions
diff --git a/lispref/variables.texi b/lispref/variables.texi
index df816f85b68..d7a5929bcfb 100644
--- a/lispref/variables.texi
+++ b/lispref/variables.texi
@@ -1185,10 +1185,10 @@ be changed with @code{setq} in any buffer; the only way to change it is
with @code{setq-default}.
@strong{Warning:} When a variable has buffer-local values in one or
-more buffers, you can get Emacs very confused by binding the variable
-with @code{let}, changing to a different current buffer in which a
-different binding is in effect, and then exiting the @code{let}. This
-can scramble the values of the buffer-local and default bindings.
+more buffers, binding the variable with @code{let} and changing to a
+different current buffer in which a different binding is in
+effect, and then exiting the @code{let}, the variable may not be
+restored to the value it had before the @code{let}.
To preserve your sanity, avoid using a variable in that way. If you
use @code{save-excursion} around each piece of code that changes to a
@@ -1197,22 +1197,23 @@ different current buffer, you will not have this problem
@example
@group
-(setq foo 'b)
+(setq foo 'g)
(set-buffer "a")
(make-local-variable 'foo)
@end group
(setq foo 'a)
(let ((foo 'temp))
+ ;; foo @result{} 'temp ; @r{let binding in buffer @samp{a}}
(set-buffer "b")
+ ;; foo @result{} 'g ; @r{the global value since foo is not local in @samp{b}}
@var{body}@dots{})
@group
-foo @result{} 'a ; @r{The old buffer-local value from buffer @samp{a}}
- ; @r{is now the default value.}
+foo @result{} 'a ; @r{we are still in buffer @samp{b}, but exiting the let}
+ ; @r{restored the local value in buffer @samp{a}}
@end group
@group
-(set-buffer "a")
-foo @result{} 'temp ; @r{The local @code{let} value that should be gone}
- ; @r{is now the buffer-local value in buffer @samp{a}.}
+(set-buffer "a") ; @r{This can be seen here:}
+foo @result{} 'a ; @r{we are back to the local value in buffer @samp{a}}
@end group
@end example