NAME

PerlIO::via::Include - PerlIO layer for including other files

SYNOPSIS

 use PerlIO::via::Include;
 PerlIO::via::Include->before( "^#include " );
 PerlIO::via::Include->after( "\n" );
 PerlIO::via::Include->regexp( qr/^#include(.*?)\n/ );

 use PerlIO::via::Include before => "^#include ", after => "\n";

 open( my $in,'<:via(Include)','file' )
  or die "Can't open file for reading: $!\n";


 open( my $out,'>:via(Include)','file' )
  or die "Can't open file for writing: $!\n";

DESCRIPTION

This module implements a PerlIO layer that includes other files, as indicated by a special string, on input and on output. It is intended as a development tool only, but may have uses outside of development.

The regular expression indicating the filename of a file to be included, can be specified either with the the before manpage and the after manpage class methods, or as a regular expression with the the regexp manpage class method.

CLASS METHODS

The following class methods allow you to alter certain characteristics of the file inclusion process. Ordinarily, you would expect these to be specified as parameters during the process of opening a file. Unfortunately, it is not yet possible to pass parameters with the PerlIO::via module.

Therefore an approach with class methods was chosen. Class methods that can also be called as key-value pairs in the use statement.

Please note that the new value of the class methods that are specified, only apply to the file handles that are opened (or to which the layer is assigned using binmode()) after they have been changed.

before

 use PerlIO::via::Include before => "^#include ";


 PerlIO::via::Include->before( "^#include " );
 my $before = PerlIO::via::Include->before;

The class method ``before'' returns the string that should be before the file specification in the regular expression that will be used to include other files. The optional input parameter specifies the string that should be before the file specification in the regular expression that will be used for any files that are opened in the future. The default is '^#include '.

See the the after manpage method for specifying the string after the filename specification. See the the regexp manpage method for specifying the regular expression as a regular expression.

after

 use PerlIO::via::Include after => "\n";


 PerlIO::via::Include->after( "\n" );
 my $after = PerlIO::via::Include->after;

The class method ``after'' returns the string that should be after the file specification in the regular expression that will be used to include other files. The optional input parameter specifies the string that should be after the file specification in the regular expression that will be used for any files that are opened in the future. The default is ``\n'' (indicating the end of the line).

See the the before manpage method for specifying the string before the filename specification. See the the regexp manpage method for specifying the regular expression as a regular expression.

regexp

 use PerlIO::via::Include regexp => qr/^#include(.*?)\n/;


 PerlIO::via::Include->regexp( qr/^#include(.*?)\n/ );
 my $regexp = PerlIO::via::Include->regexp;

The class method ``regexp'' returns the regular expression that will be used to include other files. The optional input parameter specifies the regular expression that will be used for any files that are opened in the future. The default is to use what is (implicitely) specified with the before manpage and the after manpage.

REQUIRED MODULES

 (none)

EXAMPLES

Here will be some examples, some may even be useful.

COPYRIGHT

PerlIO::via::Include - PerlIO layer for including other files