1 files changed, 25 insertions, 0 deletions

diff --git a/lispref/strings.texi b/lispref/strings.texi
index 23f679d5bb9..af5a2fa14d3 100644
--- a/lispref/strings.texi
+++ b/lispref/strings.texi
@@ -586,6 +586,7 @@ first character of @var{string} is the null character, @acronym{ASCII} code
 @example
 (string-to-char "ABC")
      @result{} 65
+
 (string-to-char "xyz")
      @result{} 120
 (string-to-char "")
@@ -1107,6 +1108,30 @@ This function returns the current buffer's case table.
 This sets the current buffer's case table to @var{table}.
 @end defun
 
+@defmac with-case-table table body@dots{}
+The @code{with-case-table} macro saves the current case table, makes
+@var{table} the current case table, evaluates the @var{body} forms,
+and finally restores the case table.  The return value is the value of
+the last form in @var{body}.  The case table is restored even in case
+of an abnormal exit via @code{throw} or error (@pxref{Nonlocal
+Exits}).
+@end defmac
+
+  Some language environments may modify the case conversions of
+@acronym{ASCII} characters; for example, in the Turkish language
+environment, the @acronym{ASCII} character @samp{I} is downcased into
+a Turkish ``dotless i''.  This can interfere with code that requires
+ordinary ASCII case conversion, such as implementations of
+@acronym{ASCII}-based network protocols.  In that case, use the
+@code{with-case-table} macro with the variable @var{ascii-case-table},
+which stores the unmodified case table for the @acronym{ASCII}
+character set.
+
+@defvar ascii-case-table
+The case table for the @acronym{ASCII} character set.  This should not be
+modified by any language environment settings.
+@end defvar
+
   The following three functions are convenient subroutines for packages
 that define non-@acronym{ASCII} character sets.  They modify the specified
 case table @var{case-table}; they also modify the standard syntax table.