error message string for flattenB
handle ()
more efficient Vec encoding
IsoGen for R&L trees; bus width font size
Int literals
Zippable, LScan, fstP, sndP
drop some IsNat constraints; LScan
Left-associated trees
triples, quads, Endo
Parallel scan
LTree, Scan
Hide TreeCat
remove VecCat and TreeCat
liftA2'''
ap'''