From: Chris Hanson <org/chris-hanson/cph>
Date: Tue, 9 Sep 2003 03:47:32 +0000 (+0000)
Subject: Document #\U+ syntax and CHAR-SET=?.
X-Git-Tag: 20090517-FFI~1815
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=3ea226dbfc3f5bfa7408cff1e3f124a03e566f33;p=mit-scheme.git

Document #\U+ syntax and CHAR-SET=?.
---

diff --git a/v7/doc/ref-manual/characters.texi b/v7/doc/ref-manual/characters.texi
index 9c4587666..c52830e9e 100644
--- a/v7/doc/ref-manual/characters.texi
+++ b/v7/doc/ref-manual/characters.texi
@@ -1,5 +1,5 @@
 @c This file is part of the MIT/GNU Scheme Reference Manual.
-@c $Id: characters.texi,v 1.3 2003/07/04 01:45:36 cph Exp $
+@c $Id: characters.texi,v 1.4 2003/09/09 03:47:32 cph Exp $
 
 @c Copyright 1991,1992,1993,1994,1995 Massachusetts Institute of Technology
 @c Copyright 1996,1997,1999,2000,2001 Massachusetts Institute of Technology
@@ -52,6 +52,23 @@ by a delimiter character such as a space or parenthesis.  Characters
 written in the @code{#\} notation are self-evaluating; you don't need to
 quote them.
 
+@findex #\U+
+In addition to the standard character syntax, MIT Scheme also supports a
+general syntax that denotes any Unicode character by its code point.
+This notation is @code{#\U+@var{code-point}}, where @var{code-point} is
+a sequence of hexadecimal digits for a valid code point.  So the above
+examples could also be written like this:
+
+@example
+@group
+#\U+61                  @r{; lowercase letter}
+#\U+41                  @r{; uppercase letter}
+#\U+28                  @r{; left parenthesis}
+#\U+20                  @r{; the space character}
+#\U+0A                  @r{; the newline character}
+@end group
+@end example
+
 @cindex bucky bit, prefix (defn)
 @cindex control, bucky bit prefix (defn)
 @cindex meta, bucky bit prefix (defn)
@@ -516,11 +533,6 @@ contain only @acronym{ISO-8859-1} characters; use the @dfn{alphabet}
 abstraction (@pxref{Unicode} if you need to cover the entire Unicode
 range.
 
-There is no meaningful external representation for character sets; use
-@code{char-set-members} to examine their contents.  There is (at
-present) no specific equivalence predicate for character sets; use
-@code{equal?} for this purpose.
-
 @deffn procedure char-set? object
 @cindex type predicate, for character set
 Returns @code{#t} if @var{object} is a character set; otherwise returns
@@ -601,6 +613,11 @@ Returns @code{#t} if @var{char} is in @var{char-set}; otherwise returns
 @code{#f}.
 @end deffn
 
+@deffn {procedure} char-set=? char-set-1 char-set-2
+Returns @code{#t} if @var{char-set-1} and @var{char-set-2} contain
+exactly the same characters; otherwise returns @code{#f}.
+@end deffn
+
 @deffn procedure char-set char @dots{}
 @cindex construction, of character set
 Returns a character set consisting of the specified @acronym{ISO-8859-1}