SwiftyExpat

Simple wrapper for the Expat XML parser.

Targets

2018-04-27: Updated to use Swift 4.0.3 (aka Xcode 9.2).

Updated to use Swift v0.2b5 (aka Xcode 7b5).

Note: The SwiftyExpat version for Swift 1.x was using a modified Expat which used blocks instead of C function pointer callbacks. Swift 2 now supports C function pointer calls and hence this project got rewritten for this.

The project includes two targets:

• SwiftyExpat
• SwiftyExpatTests

I suggest you start by looking at the SwiftyExpatTests.

SwiftyExpat

This is a tiny framework wth a small Swift class to make the API nicer. Though this is not really necessary - Expat is reasonably easy to use from Swift as-is.

let p = Expat()
  .onStartElement   { name, attrs in print("<\(name) \(attrs)")       }
  .onEndElement     { name        in print(">\(name)")                }
  .onStartNamespace { prefix, uri in print("+NS[\(prefix)] = \(uri)") }
  .onEndNamespace   { prefix      in print("-NS[\(prefix)]")          }
  .onError          { error       in print("ERROR: \(error)")         }
p.write("<hello>world</hello>")
p.close()

The raw Expat API works like this:

let p = XML_ParserCreate("UTF-8")
defer { XML_ParserFree(p) }

XML_SetStartElementHandler(p) { _, name, attrs in
  print("start tag \(String.fromCString(name)!)")
}
XML_SetEndElementHandler  (p) { _, name in
  print("end tag \(String.fromCString(name)!)")
}

XML_Parse(p, "<hello/>", 8, 0)
XML_Parse(p, "", 0, 1)

You get the idea ...

Note: The closures in the raw API cannot capture variables. If you need to pass around context (very likely ...), you need to fill the regular Expat 'user data' field (which the wrapper does, if you need an example).

SwiftyExpatTests

Just a tiny demo on how to invoke the parser.

Contact

@helje5 | helge@alwaysrightinstitute.com