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Encode::Alias(3)      User Contributed Perl Documentation     Encode::Alias(3)

NAME
       Encode::Alias - alias definitions to encodings

SYNOPSIS
	 use Encode;
	 use Encode::Alias;
	 define_alias( "newName" => ENCODING);
	 define_alias( qr/.../ => ENCODING);
	 define_alias( sub { return ENCODING if	...; } );

DESCRIPTION
       Allows newName to be used as an alias for ENCODING. ENCODING may	be
       either the name of an encoding or an encoding object (as	described in
       Encode).

       Currently the first argument to define_alias() can be specified in the
       following ways:

       As a simple string.
       As a qr// compiled regular expression, e.g.:
	     define_alias( qr/^iso8859-(\d+)$/i	=> '"iso-8859-$1"' );

	   In this case, if ENCODING is	not a reference, it is "eval"-ed in
	   order to allow $1 etc. to be	substituted.  The example is one way
	   to alias names as used in X11 fonts to the MIME names for the
	   iso-8859-* family.  Note the	double quotes inside the single
	   quotes.

	   (or,	you don't have to do this yourself because this	example	is
	   predefined)

	   If you are using a regex here, you have to use the quotes as	shown
	   or it won't work.  Also note	that regex handling is tricky even for
	   the experienced.  Use this feature with caution.

       As a code reference, e.g.:
	     define_alias( sub {shift =~ /^iso8859-(\d+)$/i ? "iso-8859-$1" : undef } );

	   The same effect as the example above	in a different way.  The
	   coderef takes the alias name	as an argument and returns a canonical
	   name	on success or undef if not.  Note the second argument is
	   ignored if provided.	 Use this with even more caution than the
	   regex version.

       Changes in code reference aliasing

       As of Encode 1.87, the older form

	 define_alias( sub { return  /^iso8859-(\d+)$/i	? "iso-8859-$1"	: undef	} );

       no longer works.

       Encode up to 1.86 internally used "local	$_" to implement this older
       form.  But consider the code below;

	 use Encode;
	 $_ = "eeeee" ;
	 while (/(e)/g)	{
	   my $utf = decode('aliased-encoding-name', $1);
	   print "position:",pos,"\n";
	 }

       Prior to	Encode 1.86 this fails because of "local $_".

   Alias overloading
       You can override	predefined aliases by simply applying define_alias().
       The new alias is	always evaluated first,	and when necessary,
       define_alias() flushes the internal cache to make the new definition
       available.

	 # redirect SHIFT_JIS to MS/IBM	Code Page 932, which is	a
	 # superset of SHIFT_JIS

	 define_alias( qr/shift.*jis$/i	 => '"cp932"' );
	 define_alias( qr/sjis$/i	 => '"cp932"' );

       If you want to zap all predefined aliases, you can use

	 Encode::Alias->undef_aliases;

       to do so.  And

	 Encode::Alias->init_aliases;

       gets the	factory	settings back.

       Note that define_alias()	will not be able to override the canonical
       name of encodings. Encodings are	first looked up	by canonical name
       before potential	aliases	are tried.

SEE ALSO
       Encode, Encode::Supported

perl v5.32.1			  2021-05-18		      Encode::Alias(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO

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