ARQ - Internal Design

@@ Incomplete / misnamed?

ARQ consists of the following parts:

The SPARQL abstract syntax tree (AST) and the SPARQL parser

The algebra generator that turns SPARQL AST into algebra expressions

Query engines to execute queries

Result set handling for the SPARQL XML results format, the JSON and text versions.

Main packages:

Package	Use
`com.hp.hpl.jena.query`	The application API
`com.hp.hpl.jena.sparql.syntax`	Abstract syntax tree
`com.hp.hpl.jena.sparql.algebra`	SPARQL algebra
`com.hp.hpl.jena.sparql.lang`	The parsers: SPARQL, ARQ, RDQL
`com.hp.hpl.jena.sparql.expr`	Expression code.
`com.hp.hpl.jena.sparql.serializer`	Output in SPARQL, ARQ forms, in SPARQL syntax, in an abstract form (useful in debugging) and in XML.
`com.hp.hpl.jena.sparql.engine`	The abstraction of a query engine.
`com.hp.hpl.jena.sparql.engine.main`	The usual query engine.
`com.hp.hpl.jena.sparql.engine.ref`	The reference query engine (and quad version)

Key Execution Classes