Yet another XML Parser

This parser was built with two main goals:

binary parsing
Namespace specific parsing

It uses the parser_pt parse transform (aka don't write these) for writing the actual parser.

Components

src/parser_pt.erl Will generate simple parsers from a specification embedded in the erlang code.
src/exemell.erl The main XML Parser, the parser is strickly whitespace preserving.
src/exemellp.erl Xml output, no pretty printing, and behaviour for xml serializable things. Defines Module:xml(exemellp:state(),Module()) -> iolist(), and provides xml(tag(),[{tag(),iolist()}],[child()],exemellp:state()) -> iolist() as the preferred way of implementing the callback.
src/exemell_parser.erl behaviour for parser callback modules (and default implementation)
src/exemell_namespace.erl behaviour for namespace callback and implementation of the none namespace.
src/exemell_namespace_xml.erl implementation of the xml: namespace.
src/exemell_block.erl and src/exemell_blob.erl callbacks (and default implementations) for the block creation.
include/xml.hrl Defines the record generated by the parser when reverting to pseudo DOM mode.
include/exemell.hrl Exposes the internal state of full parser, useful if you wish to set your own entity handling, meta handling or p.i. handling (or even to rewire the namespace handling).
src/parser.hrl The actual XML parser used by exemell.erl. The parser is not for the faint of heart but should make it obvious how to use parser_pt.erl.

Performance

It's not the fastest parser out there, but its reasonably fast a very rough test places the parser at about:

~10% slower then erlsom
twice as fast as xmerl As with any performance rating, take them with a lot of salt, and do your own measurements.

Caviats

No validation other then basic wellformedness is done (the parser will silently ignore missing close tags)
The parser is hard coded to UTF8 encoding
Other than sanity checking there's no testing done.
Not all features are implemented yet (particularly skip and blob are not implemented).
There is an unavoidable warning about an undefined behaviour exemell (erlc is not favourable to self referentiality).

Todos

Proper test cases, the modules are type annotated and dialyzer seems happy enough.
Figure out how to make dialyzer like a polymorphic version of the module.

Benchmark

A simple parsing benchmark is included, though its results are likely meaningless for practical purposes. Enter the path(s)s to your favourite example XML in to test/exemell_bennchmar.erl and then make benchmark. To include erlsom in the benchmark uncomment the dependency in rebar.config and make dependencies; make all.

tiash / exemell