The basevector is an Arachne module consisting of a vector (or vec) of bases. Basevectors are used to represent DNA sequences, including kmers, reads, and contigs. The basevector module efficiently stores base information in binary format, representing each base as a pair of bits (which is possible because there are 4 = 22 bases); thus for a sequence of length N, only ceil(N/4) bytes of storage are needed. This is why kmers in Arachne tend to have k divisible by 4.
The function basevector::Print is useful for producing fasta-format output.