Section: Software

ATerm

Participant : Pierre-Etienne Moreau [correspondant] .

ATerm (short for Annotated Term) is an abstract data type designed for the exchange of tree-like data structures between distributed applications.

The ATerm library forms a comprehensive procedural interface which enables creation and manipulation of ATerms in C and Java. The ATerm implementation is based on maximal subterm sharing and automatic garbage collection.

A binary exchange format for the concise representation of ATerms (sharing preserved) allows the fast exchange of ATerms between applications. In a typical application—parse trees which contain considerable redundant information—less than 2 bytes are needed to represent a node in memory, and less than 2 bits are needed to represent it in binary format. The implementation of ATerms scales up to the manipulation of ATerms in the giga-byte range.

The ATerm library provides a comprehensive interface in C and Java to handle the annotated term data-type in an efficient manner.

We are involved (with the CWI) in the implementation of the Java version, as well as in the garbage collector of the C version. The Java version of the ATerm library is used in particular by Tom.

The ATerm library is documented, maintained, and available at the following address: http://www.meta-environment.org/Meta-Environment/ATerms .