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, type

Remove the specified magic from the scalar
(DANGEROUS!), L<perlguts>. L<Untaint>, for a similar but different
interface.

=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:	1.6
Committed:	Sat Apr 24 06:23:12 2004 UTC (20 years ago) by root
Branch:	MAIN
Changes since 1.5:	+6 -4 lines
Log Message:	* empty log message *
#	Content
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	: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	:ok all *ok-functions.
21
22	=over 4
23
24	=cut
25
26	package Convert::Scalar;
27
28	BEGIN {
29	$VERSION = '1.0';
30	@ISA = qw(Exporter);
31	@EXPORT_OK = qw(weaken unmagic grow);
32	%EXPORT_TAGS = (
33	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	ok => [qw(ok uok rok pok nok niok)],
37	);
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	=item untaint scalar, type
116
117	Remove the specified magic from the scalar
118	(DANGEROUS!), L<perlguts>. L<Untaint>, for a similar but different
119	interface.
120
121	=item grow scalar, newlen
122
123	Sets the memory area used for the scalar to the given length, if the
124	current length is less than the new value. This does not affect the
125	contents of the scalar, but is only useful to "pre-allocate" memory space
126	if you know the scalar will grow. The return value is the modified scalar
127	(the scalar is modified in-place).
128
129	=item refcnt scalar[, newrefcnt]
130
131	Returns the current reference count of the given scalar and optionally sets it to
132	the given reference count.
133
134	=item refcnt_inc scalar
135
136	Increments the reference count of the given scalar inplace.
137
138	=item refcnt_dec scalar
139
140	Decrements the reference count of the given scalar inplace. Use C<weaken>
141	instead if you understand what this function is fore. Better yet: don't
142	use this module in this case.
143
144	=item refcnt_rv scalar[, newrefcnt]
145
146	Works like C<refcnt>, but dereferences the given reference first. This is
147	useful to find the reference count of arrays or hashes, which cnanot be
148	passed directly. Remember that taking a reference of some object increases
149	it's reference count, so the reference count used by the C<*_rv>-functions
150	tend to be one higher.
151
152	=item refcnt_inc_rv scalar
153
154	Works like C<refcnt_inc>, but dereferences the given reference first.
155
156	=item refcnt_dec_rv scalar
157
158	Works like C<refcnt_dec>, but dereferences the given reference first.
159
160	=item ok scalar
161
162	=item uok scalar
163
164	=item rok scalar
165
166	=item pok scalar
167
168	=item nok scalar
169
170	=item niok scalar
171
172	Calls SvOK, SvUOK, SvROK, SvPOK, SvNOK or SvNIOK on the given scalar,
173	respectively.
174
175	=cut
176
177	1;
178
179	=back
180
181	=head2 CANDIDATES FOR FUTURE RELEASES
182
183	The following API functions (L<perlapi>) are considered for future
184	inclusion in this module If you want them, write me.
185
186	sv_upgrade
187	sv_pvn_force
188	sv_pvutf8n_force
189	the sv2xx family
190
191	=head1 AUTHOR
192
193	Marc Lehmann <pcg@goof.com>
194	http://www.goof.com/pcg/marc/
195
196	=cut
197