Convert-Scalar/Scalar.pm

=head1 NAME

Convert::Scalar - convert between different representations of perl scalars

=head1 SYNOPSIS

 use Convert::Scalar;

=head1 DESCRIPTION

This module exports various internal perl methods that change the internal
representation or state of a perl scalar. All of these work in-place, that
is, they modify their scalar argument. No functions are exported by default.

The following export tags exist:

 :utf8   all functions with utf8 in their name
 :taint  all functions with taint in their name
 :refcnt all functions with refcnt in their name
 :ok     all *ok-functions.

=over 4

=cut

package Convert::Scalar;

BEGIN {
   $VERSION = '1.0';
   @ISA = qw(Exporter);
   @EXPORT_OK = qw(weaken unmagic grow);
   %EXPORT_TAGS = (
      taint  => [qw(taint untaint tainted)],
      utf8   => [qw(utf8 utf8_on utf8_off utf8_valid utf8_upgrade utf8_downgrade utf8_encode utf8_decode utf8_length)],
      refcnt => [qw(refcnt refcnt_inc refcnt_dec refcnt_rv refcnt_inc_rv refcnt_dec_rv)],
      ok     => [qw(ok uok rok pok nok niok)],
   );

   require Exporter;
   Exporter::export_ok_tags(keys %EXPORT_TAGS);

   require XSLoader;
   XSLoader::load Convert::Scalar, $VERSION;
}

=item utf8 scalar[, mode]

Returns true when the given scalar is marked as utf8, false otherwise. If
the optional mode argument is given, also forces the interpretation of the
string to utf8 (mode true) or plain bytes (mode false). The actual (byte-)
content is not changed. The return value always reflects the state before
any modification is done.

This function is useful when you "import" utf8-data into perl, or when
some external function (e.g. storing/retrieving from a database) removes
the utf8-flag.

=item utf8_on scalar

Similar to C<utf8 scalar, 1>, but additionally returns the scalar (the
argument is still modified in-place).

=item utf8_off scalar

Similar to C<utf8 scalar, 0>, but additionally returns the scalar (the
argument is still modified in-place).

=item utf8_valid scalar [Perl 5.7]

Returns true if the bytes inside the scalar form a valid utf8 string,
false otherwise (the check is independent of the actual encoding perl
thinks the string is in).

=item utf8_upgrade scalar

Convert the string content of the scalar in-place to its UTF8-encoded form
(and also returns it).

=item utf8_downgrade scalar[, fail_ok=0]

Attempt to convert the string content of the scalar from UTF8-encoded to
ISO-8859-1. This may not be possible if the string contains characters
that cannot be represented in a single byte; if this is the case, it
leaves the scalar unchanged and either returns false or, if C<fail_ok> is
not true (the default), croaks.

=item utf8_encode scalar

Convert the string value of the scalar to UTF8-encoded, but then turn off
the C<SvUTF8> flag so that it looks like bytes to perl again. (Might be
removed in future versions).

=item utf8_length scalar

Returns the number of characters in the string, counting wide UTF8
characters as a single character, independent of wether the scalar is
marked as containing bytes or mulitbyte characters.

=item unmagic scalar

Removes magic from the scalar.

=item weaken scalar

Weaken a reference. (See also L<WeakRef>).

=item taint scalar

Taint the scalar.

=item tainted scalar

returns true when the scalar is tainted, false otherwise.

=item untaint scalar

Remove the tainted flag from the specified scalar.

=item grow scalar, newlen

Sets the memory area used for the scalar to the given length, if the
current length is less than the new value. This does not affect the
contents of the scalar, but is only useful to "pre-allocate" memory space
if you know the scalar will grow. The return value is the modified scalar
(the scalar is modified in-place).

=item refcnt scalar[, newrefcnt]

Returns the current reference count of the given scalar and optionally sets it to
the given reference count.

=item refcnt_inc scalar

Increments the reference count of the given scalar inplace.

=item refcnt_dec scalar

Decrements the reference count of the given scalar inplace. Use C<weaken>
instead if you understand what this function is fore. Better yet: don't
use this module in this case.

=item refcnt_rv scalar[, newrefcnt]

Works like C<refcnt>, but dereferences the given reference first. This is
useful to find the reference count of arrays or hashes, which cnanot be
passed directly. Remember that taking a reference of some object increases
it's reference count, so the reference count used by the C<*_rv>-functions
tend to be one higher.

=item refcnt_inc_rv scalar

Works like C<refcnt_inc>, but dereferences the given reference first.

=item refcnt_dec_rv scalar

Works like C<refcnt_dec>, but dereferences the given reference first.

=item ok scalar

=item uok scalar

=item rok scalar

=item pok scalar

=item nok scalar

=item niok scalar

Calls SvOK, SvUOK, SvROK, SvPOK, SvNOK or SvNIOK on the given scalar,
respectively.

=cut

1;

=back

=head2 CANDIDATES FOR FUTURE RELEASES

The following API functions (L<perlapi>) are considered for future
inclusion in this module If you want them, write me.

 sv_upgrade
 sv_pvn_force
 sv_pvutf8n_force
 the sv2xx family

=head1 AUTHOR

 Marc Lehmann <pcg@goof.com>
 http://www.goof.com/pcg/marc/

=cut

Revision:	1.7
Committed:	Sat Apr 24 06:36:50 2004 UTC (20 years ago) by root
Branch:	MAIN
Changes since 1.6:	+2 -4 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			Convert::Scalar - convert between different representations of perl scalars
4
5			=head1 SYNOPSIS
6
7			use Convert::Scalar;
8
9			=head1 DESCRIPTION
10
11			This module exports various internal perl methods that change the internal
12			representation or state of a perl scalar. All of these work in-place, that
13			is, they modify their scalar argument. No functions are exported by default.
14
15			The following export tags exist:
16
17	root	1.2	:utf8 all functions with utf8 in their name
18			:taint all functions with taint in their name
19			:refcnt all functions with refcnt in their name
20	root	1.5	:ok all *ok-functions.
21	root	1.1
22			=over 4
23
24			=cut
25
26			package Convert::Scalar;
27
28			BEGIN {
29	root	1.6	$VERSION = '1.0';
30	root	1.1	@ISA = qw(Exporter);
31			@EXPORT_OK = qw(weaken unmagic grow);
32			%EXPORT_TAGS = (
33	root	1.2	taint => [qw(taint untaint tainted)],
34			utf8 => [qw(utf8 utf8_on utf8_off utf8_valid utf8_upgrade utf8_downgrade utf8_encode utf8_decode utf8_length)],
35			refcnt => [qw(refcnt refcnt_inc refcnt_dec refcnt_rv refcnt_inc_rv refcnt_dec_rv)],
36	root	1.5	ok => [qw(ok uok rok pok nok niok)],
37	root	1.1	);
38
39			require Exporter;
40			Exporter::export_ok_tags(keys %EXPORT_TAGS);
41
42			require XSLoader;
43			XSLoader::load Convert::Scalar, $VERSION;
44			}
45
46			=item utf8 scalar[, mode]
47
48			Returns true when the given scalar is marked as utf8, false otherwise. If
49			the optional mode argument is given, also forces the interpretation of the
50			string to utf8 (mode true) or plain bytes (mode false). The actual (byte-)
51			content is not changed. The return value always reflects the state before
52			any modification is done.
53
54			This function is useful when you "import" utf8-data into perl, or when
55			some external function (e.g. storing/retrieving from a database) removes
56			the utf8-flag.
57
58			=item utf8_on scalar
59
60			Similar to C<utf8 scalar, 1>, but additionally returns the scalar (the
61			argument is still modified in-place).
62
63			=item utf8_off scalar
64
65			Similar to C<utf8 scalar, 0>, but additionally returns the scalar (the
66			argument is still modified in-place).
67
68			=item utf8_valid scalar [Perl 5.7]
69
70			Returns true if the bytes inside the scalar form a valid utf8 string,
71			false otherwise (the check is independent of the actual encoding perl
72			thinks the string is in).
73
74			=item utf8_upgrade scalar
75
76			Convert the string content of the scalar in-place to its UTF8-encoded form
77			(and also returns it).
78
79			=item utf8_downgrade scalar[, fail_ok=0]
80
81			Attempt to convert the string content of the scalar from UTF8-encoded to
82			ISO-8859-1. This may not be possible if the string contains characters
83			that cannot be represented in a single byte; if this is the case, it
84			leaves the scalar unchanged and either returns false or, if C<fail_ok> is
85			not true (the default), croaks.
86
87			=item utf8_encode scalar
88
89			Convert the string value of the scalar to UTF8-encoded, but then turn off
90			the C<SvUTF8> flag so that it looks like bytes to perl again. (Might be
91			removed in future versions).
92
93			=item utf8_length scalar
94
95			Returns the number of characters in the string, counting wide UTF8
96			characters as a single character, independent of wether the scalar is
97			marked as containing bytes or mulitbyte characters.
98
99			=item unmagic scalar
100
101			Removes magic from the scalar.
102
103			=item weaken scalar
104
105			Weaken a reference. (See also L<WeakRef>).
106
107			=item taint scalar
108
109			Taint the scalar.
110
111			=item tainted scalar
112
113			returns true when the scalar is tainted, false otherwise.
114
115	root	1.7	=item untaint scalar
116	root	1.1
117	root	1.7	Remove the tainted flag from the specified scalar.
118	root	1.1
119			=item grow scalar, newlen
120
121			Sets the memory area used for the scalar to the given length, if the
122			current length is less than the new value. This does not affect the
123			contents of the scalar, but is only useful to "pre-allocate" memory space
124			if you know the scalar will grow. The return value is the modified scalar
125			(the scalar is modified in-place).
126	root	1.2
127			=item refcnt scalar[, newrefcnt]
128
129	root	1.3	Returns the current reference count of the given scalar and optionally sets it to
130	root	1.2	the given reference count.
131
132			=item refcnt_inc scalar
133
134			Increments the reference count of the given scalar inplace.
135
136			=item refcnt_dec scalar
137
138			Decrements the reference count of the given scalar inplace. Use C<weaken>
139			instead if you understand what this function is fore. Better yet: don't
140			use this module in this case.
141
142			=item refcnt_rv scalar[, newrefcnt]
143
144	root	1.6	Works like C<refcnt>, but dereferences the given reference first. This is
145			useful to find the reference count of arrays or hashes, which cnanot be
146			passed directly. Remember that taking a reference of some object increases
147			it's reference count, so the reference count used by the C<*_rv>-functions
148			tend to be one higher.
149	root	1.2
150			=item refcnt_inc_rv scalar
151
152			Works like C<refcnt_inc>, but dereferences the given reference first.
153
154			=item refcnt_dec_rv scalar
155
156			Works like C<refcnt_dec>, but dereferences the given reference first.
157	root	1.5
158			=item ok scalar
159
160			=item uok scalar
161
162			=item rok scalar
163
164			=item pok scalar
165
166			=item nok scalar
167
168			=item niok scalar
169
170			Calls SvOK, SvUOK, SvROK, SvPOK, SvNOK or SvNIOK on the given scalar,
171			respectively.
172	root	1.1
173			=cut
174
175			1;
176
177			=back
178
179			=head2 CANDIDATES FOR FUTURE RELEASES
180
181			The following API functions (L<perlapi>) are considered for future
182			inclusion in this module If you want them, write me.
183
184			sv_upgrade
185			sv_pvn_force
186			sv_pvutf8n_force
187			the sv2xx family
188
189			=head1 AUTHOR
190
191			Marc Lehmann <pcg@goof.com>
192			http://www.goof.com/pcg/marc/
193
194			=cut
195