NAME

XML::Invisible - transform "invisible XML" documents into XML using a grammar

SYNOPSIS

  use XML::Invisible qw(make_parser);
  my $transformer = make_parser(from_file($ixmlspec));
  my $xmldoc = $transformer->(from_file($ixml_input));
  to_file($outputfile, $xmldoc->toStringC14N(1));

  # or, with conventional pre-compiled Pegex grammar
  my $parser = Pegex::Parser->new(
    grammar => My::Thing::Grammar->new,
    receiver => XML::Invisible::Receiver->new,
  );
  my $got = $parser->parse($input);

  # from command line
  cpanm XML::Invisible XML::Twig
  perl -MXML::Invisible=make_parser -e \
    'print make_parser(join "", <>)->("(a+b)")->toStringC14N(1)' \
    examples/arith-grammar.ixml | xml_pp

DESCRIPTION

An implementation of Steven Pemberton's Invisible XML concept, using Pegex. Supply it with your grammar, in Pegex format (slightly different from Steven's specification due to differences between his notation and Pegex's), it returns you a function, which you can call to transform "invisible XML" documents into actual XML.

This is largely a Pegex "receiver" class that exploits the + and - syntax in rules in slightly unintended ways, and a wrapper to make this operate.

GRAMMAR SYNTAX

See Pegex::Syntax. Generally, all rules will result in an XML element. All terminals will need to capture with () (see example below).

However, if you specify a dependent token with + it will instead become an attribute (equivalent of Steven's @). If -, this will "flatten" (equivalent of Steven's -) - the children will be included without making an element of that node. Since in Pegex any element can be skipped entirely with ., you can use that instead of - to omit terminals.

E.g.

  expr: +open -arith +close
  open: /( LPAREN )/
  close: /( RPAREN )/
  arith: left -op right
  left: +name
  right: -name
  name: /(a)/ | /(b)/
  op: +sign
  sign: /( PLUS )/

When given (a+b) yields:

  <expr open="(" sign="+" close=")">
    <left name="a"/>
    <right>b</right>
  </expr>

FUNCTIONS

make_parser

Exportable. Returns a function that when called with an "invisible XML" document, it will return an object of class XML::LibXML::Document.

Arguments:

an "invisible XML" grammar specification, in Pegex format

ast2xml

Exportable. The function used by "make_parser" to turn an AST from XML::Invisible::Receiver into an object of class XML::LibXML::Document.

Arguments:

an AST from XML::Invisible::Receiver

DEBUGGING

To debug, set environment variable XML_INVISIBLE_DEBUG to a true value.

SEE ALSO

Pegex

https://homepages.cwi.nl/~steven/ixml/ - Steven Pemberton's Invisible XML page

AUTHOR

Ed J, <etj at cpan.org>

BUGS

Please report any bugs or feature requests on https://github.com/mohawk2/xml-invisible/issues.

Or, if you prefer email and/or RT: to bug-xml-invisible at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=XML-Invisible. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

LICENSE AND COPYRIGHT

Copyright 2018 Ed J.

This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at:

http://www.perlfoundation.org/artistic_license_2_0