consider switching from REXML to nokogiri and/or, maybe, ox.

XML::XXPath: Write a real XPath parser eventually

XML::XXPath: avoid duplicates in path.all(node) result arrays when using the descendants (“//”) axis

invent an XPath-like language for Ruby object graphs (i.e. a language that is to Ruby object graphs what XPath is to XML trees). Use expressions in that language as a generalization of “attribute names” (e.g. the 1st parameter to single attribute node factory methods). The language could more or less be Ruby itself, but the write support would need some extra work…

XML::XXPath:

• implement .[@attrname] steps

  • returns the context node iff it contains an attrname attribute

  • doesn't work properly in REXML::XPath?

• implement *[@attrname] steps

• implement *[@attrname='attrvalue'] steps

• id/idref support (write support possible?)

XML::Mapping: make SubObjectBaseNode a mixin instead of a subclass of SingleAttributeNode (“mapping sub-objects” and “mapping to a single attribute” are orthogonal concepts; inheritance is bad design here)

documentation:

• consider switching to YARD

  • reasons: parameter/return type metadata, (maybe) plugin for the code snippet inclusion stuff

• user_manual:

  • document/show usage of default_when_xpath_err outside node type implementations

• user_manual_xxpath:

  • mention new step types, new axes, xml/xpath_methods

XML::XXPath/XML::Mapping: support for XML namespaces in XML::XXPath (match nodes with specific namespaces only) and XML::Mapping (use_namespace etc.)

add streaming input/output to XML::Mapping, i.e. SAX-based input in addition to the current REXML/DOM - based one. Probably won't be implementable for some more complicated XPaths – raise meaningful exceptions in those cases.

• would need support in xxpath

• should probably be built on top of the Ruby 2.0 lazy enumeration stuff

XML::XXPath/XML::Mapping: add XML text nodes (the sub-node of an element node that contains that element's text) first-class to XML::XXPath. Use it for things like text_node :contents, “text()”.

Along those lines: promote XPath node “unspecifiedness” from an attribute to a REXML node object of “unspecified” class that's turned into an attribute/element/text node when necessary

(eventually, maybe) provide a “scaffolding” feature to automatically turn a dtd/schema into a set of node type definitions or even a set of mapping classes