Look into ASIS (Ada Semantic Interface Specification) at
ASIS is a vendor-independent standard API that offers both syntactic and
semantic information about Ada programs and compilation units.
ASIS for Ada 95 is available for GNAT and will be selectively available
for ObjectAda Intel around the end of September.
Daniel, if you or anyone else has questions about ASIS and what it can do,
I will be here to answer them.
What kind of tools would you want to build using an Ada parser?