Language for Embedded QuEry and TraverSAl (LEESA)


LEESA is a new way of writing traversals over typed object structures, such as XML documents and domain-specific models. LEESA (Language for Embedded quEry and traverSAl) is a domain-specific embedded language (DSEL) in C++ that:
  • Provides a succinct and expressive notation for writing object structure traversal (examples).
  • Supports hierarchical visitors, decouples traversals from visitation actions, and improves visitor and traversal reusability.
  • Provides C++ template-based combinators to write tree traversals in a strategic programming style.
  • Supports XPath-like axis-oriented notation including structure-shyness (e.g., descendant-axis and wildcards).
  • Reports any type related errors in the query at compile-time.
  • Significantly reduces the development cost of programs operating on complex object structures (e.g., XML document traversal, domain-specific modeling language (DSML) interpreters) compared to the traditional techniques.
LEESA is embedded in C++ using sophisticated generic and meta programming techniques. LEESA's toolchain supports the following XML data-binding technologies: See the comparison of XML traversal code in driver.cxx with and without LEESA. This program uses library.xsd and library.xml.

Typed XML programming

Typed XML programing identifies the lack of fidelity in contemporary X-to-O mapping (XML data binding) tools towards supporting XML semantics and programming patterns & practices native to the XML domain. LEESA, however, recognizes the practical usefulness of these mappings and attempts to improve the extraction of typed data by incorporating the idioms of XML querying (think XPath axes, wildcards) without losing the grip on types. In that sense it supports typed XML programming and alleviates the disappointment of a XML programmer in the typed world. See some examples.

Research papers

  1. Toward Native XML Processing Using Multi-paradigm Design in C++ in the 5th Annual Boost Conference (BoostCon-2011) (slides) (video)
  2. LEESA: Embedding Strategic and XPath-like Object Structure Traversals in C++ published in the IFIP Working Conference on Domain Specific Languages (DSL WC), 2009, Oxford UK (slides)
  3. An Embedded Declarative Language for Hierarchical Object Structure Traversal published in the 2nd International Workshop on Domain-Specific Program Development (DSPD), GPCE 2008, Nashville, Tennessee, October 22, 2008 (slides)

Downloading LEESA

There are two ways to obtain LEESA.
  1. Download (The latest and greatest changes may not be available)
  2. Use subversion (svn) to checkout LEESA from repository. You may need to install a subversion client. Sliksvn is a good svn client. The command to checkout LEESA sources, documentation, and tests is given below:

    svn co svn:// LEESA


XML Processing Using Strongly-Typed XPath-like Queries in C++ from Sumant Tambe on Vimeo.


Sumant Tambe (sutambe at dre d0t vanderbilt d0t edu)