Syntactic sugar: XBLY (zee-blee) is (XML (But (Lispy)))
XML is a powerful language with lots of tooling: schemas, XPath, XSLT, validators, etc.
Unfortunately, it's a pain to read and write by hand. There's no inherent reason why: it's only an accident of history that we're not currently authoring structured documents with S-expressions and calling it the Common Business Communication Language instead.
Enter XBLY. XBLY is a language that can be translated into XML documents or XML fragments using an absurdly simple parser. We include an implementation in C that you should have little trouble translating into your language of choice.
The parser is so simple because it has no concept of a document - it just transforms text using seven states, two bytes of context, and a small stack for element names.
<?xml version="1.0" encoding="utf-8"?>
(basket
(item Apple)
(item \quantity="2" Banana)
(item Ginger \(fresh\))
)
<?xml version="1.0" encoding="utf-8"?>
<basket>
<item>Apple</item>
<item quantity="2">Banana</item>
<item>Ginger (fresh)</item>
</basket>
The XML output may not be binary identical to this example because the XML output may contain extra whitespace inside tags. The result will be semantically equivalent. Your XML process ends in XML Normalization or Canonicalized XML anyway, right?
This example demonstrates some subtle differences in use of whitespace.
<?xml version="1.0" ?>
<!DOCTYPE html>
(html \xmlns="http://www.w3.org/1999/xhtml"
(head (title XHTML Example))
(body
(p Hello (b World))
(hr \id="foo")
(p Hello(u \ World ))
)
)
<?xml version="1.0" ?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head><title>XHTML Example</title></head>
<body>
<p>Hello <b>World</b></p>
<hr id="foo"/>
<p>Hello<u> World </u></p>
</body>
</html>
Note that XHTML must be served as application/xhtml+xml, not as HTML.
If you want to generate HTML then you must transform the input once
more to meet HTML Compatibility Guidelines
e.g. rewrite <script src="..." /> to <script src="..."></script>, etc.
This can be done with XLST.
As a simple workaround, you can add some safe inner content instead, like a JavaScript comment:
(script \src="..." //)
XBLY copies verbatim everything up to the first opening parenthesis, so we've been able to include XML and HTML5 declarations. You can leave them out if you want: they have no special meaning to XBLY.
(hello (world))
<hello><world /></hello>
Just to note about escaping with backslash:
In text content a backslash can escape explicit whitespace, the opening and closing parenthesis, or a literal backslash.
You might think the same would work with quote character in attributes. Sorry,
but you have to use XML rules here and use " or '. It's
worth it to keep the parser simple and easy to translate to other langauges.
(weather \what='it's raining men' \advice="Don't you lose your head!")
<weather what='it's raining men' advice="Don't you lose your head!" />
We include a simple command-line program to convert a XBLY text stream to XML documents or fragments.
Clone the repo
git clone git@github.com:tawesoft/xbly.git
cd xbly
Compile xbly.c
cc -std=c99 -Wall -Wextra xbly.c -o xbly
python3 test.py # optional
Translate XBLY on the command-line
echo "(foo (bar))" | ./xbly
cat input.xbly | ./xbly > output.xml
Install XBLY
sudo cp xbly /usr/local/xbly
XBLY is licensed as MIT-0 / MIT No Attribution so you can use it freely without credit. See COPYING.txt for the full terms.