Improve character name escapes

* doc/lispref/nonascii.texi (Character Properties):
Avoid duplication of Unicode names.  Reformat examples to fit in
narrow pages.
* doc/lispref/objects.texi (General Escape Syntax):
Simplify and better-organize explanation of \N{...} escapes.
* src/character.h (CHAR_SURROGATE_PAIR_P): Remove; unused.
(char_surrogate_p): New inline function.
* src/lread.c: Do not include string.h; no longer needed.
(invalid_character_name, check_scalar_value): Remove; the ideas
behind these functions are now bundled into character_name_to_code.
(character_name_to_code): Remove undocumented support for "CJK
IDEOGRAPH-XXXX" names, as "U+XXXX" suffices.  Reject monstrosities
like "\N{U+-0}" and null bytes in \N escapes.  Reject floating
point in \N escapes instead of returning garbage.  Use
AUTO_STRING_WITH_LEN to lessen pressure on the garbage collector.
* test/src/lread-tests.el (lread-char-number, lread-char-name)
(lread-string-char-number, lread-string-char-name):
Test runtime behavior, not compile-time, as the test framework
is not set up to test compile-time.
(lread-char-surrogate-1, lread-char-surrogate-2)
(lread-char-surrogate-3, lread-char-surrogate-4)
(lread-string-char-number-2, lread-string-char-number-3):
New tests.
(lread-string-char-number-1): Rename from lread-string-char-number.

1 files changed, 9 insertions, 6 deletions

diff --git a/doc/lispref/nonascii.texi b/doc/lispref/nonascii.texi
index 66ad9aca71e..0e4aa86e48b 100644
--- a/doc/lispref/nonascii.texi
+++ b/doc/lispref/nonascii.texi
@@ -622,18 +622,21 @@ This function returns the value of @var{char}'s @var{propname} property.
      @result{} Nd
 @end group
 @group
-;; U+2084 SUBSCRIPT FOUR
-(get-char-code-property ?\u2084 'digit-value)
+;; U+2084
+(get-char-code-property ?\N@{SUBSCRIPT FOUR@}
+                        'digit-value)
      @result{} 4
 @end group
 @group
-;; U+2155 VULGAR FRACTION ONE FIFTH
-(get-char-code-property ?\u2155 'numeric-value)
+;; U+2155
+(get-char-code-property ?\N@{VULGAR FRACTION ONE FIFTH@}
+                        'numeric-value)
      @result{} 0.2
 @end group
 @group
-;; U+2163 ROMAN NUMERAL FOUR
-(get-char-code-property ?\N@{ROMAN NUMERAL FOUR@} 'numeric-value)
+;; U+2163
+(get-char-code-property ?\N@{ROMAN NUMERAL FOUR@}
+                        'numeric-value)
      @result{} 4
 @end group
 @group