NAME

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

SYNOPSIS

use Convert::Scalar;

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.

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.

utf8_on scalar

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

utf8_off scalar

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

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).

utf8_upgrade scalar

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

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 fail_ok is not true (the default), croaks.

utf8_encode scalar

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

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.

unmagic scalar, type

Remove the specified magic from the scalar (DANGEROUS!).

weaken scalar

Weaken a reference. (See also WeakRef).

taint scalar

Taint the scalar.

tainted scalar

returns true when the scalar is tainted, false otherwise.

untaint scalar

Remove the tainted flag from the specified scalar.

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).

refcnt scalar[, newrefcnt]

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

refcnt_inc scalar

Increments the reference count of the given scalar inplace.

refcnt_dec scalar

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

refcnt_rv scalar[, newrefcnt]

Works like 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 *_rv-functions tend to be one higher.

refcnt_inc_rv scalar

Works like refcnt_inc, but dereferences the given reference first.

refcnt_dec_rv scalar

Works like refcnt_dec, but dereferences the given reference first.

ok scalar

uok scalar

rok scalar

pok scalar

nok scalar

niok scalar

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

CANDIDATES FOR FUTURE RELEASES

The following API functions (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

AUTHOR

Marc Lehmann <schmorp@schmorp.de>
http://home.schmorp.de/