perlapi: Add docs for some case-changing macros; clarify others

The case changing macros are now almost all documented.  The exception
is toUPPER_LC, which may change in 5.19

In addition the functions in utf8.c that these macros call now refer to
them instead of having their own documentation.  People should really be
using the macros instead of calling the functions directly.  I'm not
deprecating the functions because I can't foresee the need to change
them, so code that uses them should continue to be ok.

1 files changed, 100 insertions, 7 deletions

diff --git a/handy.h b/handy.h
index 26d73661f7..af506bf811 100644
--- a/handy.h
+++ b/handy.h
@@ -700,19 +700,112 @@ Behaviour is only well defined when isXDIGIT(*str) is true.
 
 =head1 Character case changing
 
-=for apidoc Am|char|toUPPER|char ch
-Converts the specified character to uppercase, if possible; otherwise returns
-the input character itself.  Only ASCII characters are changed.  Variant
+=for apidoc Am|U8|toUPPER|U8 ch
+Converts the specified character to uppercase.  If the input is anything but an
+ASCII lowercase character, that input character itself is returned.  Variant
 C<toUPPER_A> is equivalent.
 
-=for apidoc Am|char|toLOWER|char ch
-Converts the specified character to lowercase, if possible; otherwise returns
-the input character itself.  Only ASCII characters are changed.  Variant
+=for apidoc Am|UV|toUPPER_uni|UV cp|U8* s|STRLEN* lenp
+Converts the Unicode code point C<cp> to its uppercase version, and
+stores that in UTF-8 in C<s>, and its length in bytes in C<lenp>.  Note
+that the buffer pointed to by C<s> needs to be at least C<UTF8_MAXBYTES_CASE+1>
+bytes since the uppercase version may be longer than the original character.
+
+The first code point of the uppercased version is returned
+(but note, as explained just above, that there may be more.)
+
+=for apidoc Am|UV|toUPPER_utf8|U8* p|U8* s|STRLEN* lenp
+Converts the UTF-8 encoded character at C<p> to its uppercase version, and
+stores that in UTF-8 in C<s>, and its length in bytes in C<lenp>.  Note
+that the buffer pointed to by C<s> needs to be at least C<UTF8_MAXBYTES_CASE+1>
+bytes since the uppercase version may be longer than the original character.
+
+The first code point of the uppercased version is returned
+(but note, as explained just above, that there may be more.)
+
+The input character at C<p> is assumed to be well-formed.
+
+=for apidoc Am|UV|toFOLD_uni|UV cp|U8* s|STRLEN* lenp
+Converts the Unicode code point C<cp> to its foldcase version, and
+stores that in UTF-8 in C<s>, and its length in bytes in C<lenp>.  Note
+that the buffer pointed to by C<s> needs to be at least C<UTF8_MAXBYTES_CASE+1>
+bytes since the foldcase version may be longer than the original character.
+
+The first code point of the foldcased version is returned
+(but note, as explained just above, that there may be more.)
+
+=for apidoc Am|UV|toFOLD_utf8|U8* p|U8* s|STRLEN* lenp
+Converts the UTF-8 encoded character at C<p> to its foldcase version, and
+stores that in UTF-8 in C<s>, and its length in bytes in C<lenp>.  Note
+that the buffer pointed to by C<s> needs to be at least C<UTF8_MAXBYTES_CASE+1>
+bytes since the foldcase version may be longer than the original character.
+
+The first code point of the foldcased version is returned
+(but note, as explained just above, that there may be more.)
+
+The input character at C<p> is assumed to be well-formed.
+
+=for apidoc Am|U8|toLOWER|U8 ch
+Converts the specified character to lowercase.  If the input is anything but an
+ASCII uppercase character, that input character itself is returned.  Variant
 C<toLOWER_A> is equivalent.
 
+=for apidoc Am|U8|toLOWER_L1|U8 ch
+Converts the specified Latin1 character to lowercase.  The results are undefined if
+the input doesn't fit in a byte.
+
+=for apidoc Am|U8|toLOWER_LC|U8 ch
+Converts the specified character to lowercase using the current locale's rules,
+if possible; otherwise returns the input character itself.
+
+=for apidoc Am|UV|toLOWER_uni|UV cp|U8* s|STRLEN* lenp
+Converts the Unicode code point C<cp> to its lowercase version, and
+stores that in UTF-8 in C<s>, and its length in bytes in C<lenp>.  Note
+that the buffer pointed to by C<s> needs to be at least C<UTF8_MAXBYTES_CASE+1>
+bytes since the lowercase version may be longer than the original character.
+
+The first code point of the lowercased version is returned
+(but note, as explained just above, that there may be more.)
+
+=for apidoc Am|UV|toLOWER_utf8|U8* p|U8* s|STRLEN* lenp
+Converts the UTF-8 encoded character at C<p> to its lowercase version, and
+stores that in UTF-8 in C<s>, and its length in bytes in C<lenp>.  Note
+that the buffer pointed to by C<s> needs to be at least C<UTF8_MAXBYTES_CASE+1>
+bytes since the lowercase version may be longer than the original character.
+
+The first code point of the lowercased version is returned
+(but note, as explained just above, that there may be more.)
+
+The input character at C<p> is assumed to be well-formed.
+
+=for apidoc Am|U8|toLOWER_LC|U8 ch
+Converts the specified character to lowercase using the current locale's rules,
+if possible; otherwise returns the input character itself.
+
+=for apidoc Am|UV|toTITLE_uni|UV cp|U8* s|STRLEN* lenp
+Converts the Unicode code point C<cp> to its titlecase version, and
+stores that in UTF-8 in C<s>, and its length in bytes in C<lenp>.  Note
+that the buffer pointed to by C<s> needs to be at least C<UTF8_MAXBYTES_CASE+1>
+bytes since the titlecase version may be longer than the original character.
+
+The first code point of the titlecased version is returned
+(but note, as explained just above, that there may be more.)
+
+=for apidoc Am|UV|toTITLE_utf8|U8* p|U8* s|STRLEN* lenp
+Converts the UTF-8 encoded character at C<p> to its titlecase version, and
+stores that in UTF-8 in C<s>, and its length in bytes in C<lenp>.  Note
+that the buffer pointed to by C<s> needs to be at least C<UTF8_MAXBYTES_CASE+1>
+bytes since the titlecase version may be longer than the original character.
+
+The first code point of the titlecased version is returned
+(but note, as explained just above, that there may be more.)
+
+The input character at C<p> is assumed to be well-formed.
+
 =cut
 
-XXX Still undocumented isVERTWS_uni and _utf8, and the other toUPPER etc functions
+XXX Still undocumented isVERTWS_uni and _utf8; it's unclear what their names
+really should be.  Also toUPPER_LC, which is subject to change.
 
 Note that these macros are repeated in Devel::PPPort, so should also be
 patched there.  The file as of this writing is cpan/Devel-PPPort/parts/inc/misc