Parser mit Ragel – komplizierte Grammatiken und rattenschnelles XML.
Warum Parser bauen?
Was spricht gegen Ad-Hoc Parsing (a.k.a. Gefrickel)?
Quelltext Impression
Wie komme ich drauf?
Anschnallen: Die Bausteine
Beispiel: SVG Path Parser
Beispiel: XML Parser
Ausblick: Zustandsautomaten
Vielen Dank
Die Folien vom Vortrag am 22. September bei den CocoaHeads München.
Having a validating parser in place can reduce the required code to parse XML a lot – you know very well what you actually get. As mentioned in my last post about RELAX NG & trang, I prefer RELAX NG over W3C XML Schema – which doesn’t matter anyway because Apple’s suggested XML parser …
e.g. when handling RESTful APIs you may want to validate the response XML – a custom one in most cases.
I typically use tools already installed on every Mac and fire a http GET request with curl and immediately check it with xmllint like
$ curl http://www.heise.de/newsticker/heise-atom.xml | xmllint –format –schema myschema.xsd -
But I just don’t …
There’s a spec at the w3c about compressing (XML) named “Efficient XML Interchange” Format taking into account the grammar and likelihood of atoms within the document. They indeed use something similar the the Huffman Coding.
The results are quite impressive – nice charts!