The Annotated Term Format ATerm
has been chosen as a common interchange format for CoFI tools.
It offers a tree representation for various objects
(programs, specifications, abstract syntax trees, proofs...).
It provide annotations to store computed results relevant
for other tools.
The ATerm format specialised for CASL is CasFix.
In the Aterm
Library Aterms and associated operations in C and JAVA are available
to parse and unparse Aterms, create and manipulate them.