ROOTS

synchronized read access to cache file -- avoid potential conflict with ongoing write (which is non-atomic);
clarified signature -- cache init is unsynchronized and hopefully used at most once per file;

src/Pure
src/FOL
src/HOL
src/ZF
src/CCL
src/CTT
src/Cube
src/FOLP
src/LCF
src/Sequents
src/Doc