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dynamic

NAME

PerlIO::via::dynamic − dynamic PerlIO layers

SYNOPSIS

 open $fh, $fname;
 $p = PerlIO::via::dynamic−>new
  (translate =>
    sub { $_[1] =~ s/\$Filename[:\w\s\−\.\/\\]*\$/\$Filename: $fname\$/e},
   untranslate =>
    sub { $_[1] =~ s/\$Filename[:\w\s\−\.\/\\]*\$/\$Filename\$/});
 $p−>via ($fh);
 binmode $fh, $p−>via; # deprecated

DESCRIPTION

"PerlIO::via::dynamic" is used for creating dynamic PerlIO layers. It is useful when the behavior or the layer depends on variables. You should not use this module as via layer directly (ie :via(dynamic)).

Use the constructor to create new layers, with two arguments: translate and untranslate. Then use "$p−"via ($fh)> to wrap the handle. Once <$fh> is destroyed, the temporary namespace for the IO layer will be removed.

Note that PerlIO::via::dynamic uses the scalar fields to reference to the object representing the dynamic namespace.

OPTIONS

translate

A function that translate buffer upon write.

untranslate

A function that translate buffer upon read.

use_read

Use "READ" instead of "FILL" for the layer. Useful when caller expect exact amount of data from read, and the "untranslate" function might return different length.

By default "PerlIO::via::dynamic" creates line-based layer to make "translate" implementation easier.

AUTHORS

Chia-liang Kao <clkao AT clkao DOT org>

COPYRIGHT

Copyright 2004 by Chia-liang Kao <clkao AT clkao DOT org>.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

See <http://www.perl.com/perl/misc/Artistic.html>

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