Synthesis backend tools Petrify and MPSat use SIS Genlib format to specify gate library for technology mapping. Detailed specification of the format can be found in SIS Genlib format documentation. Automated conversion from popular gate libraries is also possible, e.g. Converter from Synopsys Liberty.
Example specifications:
GATE AND2 16 O=A*B; PIN * NONINV 1 999 1 0.2 1 0.2
LATCH C2 20 Q=A*B+(A+B)*Q_NEXT; PIN A NONINV 1 999 1 0.2 1 0.2 PIN B NONINV 1 999 1 0.2 1 0.2 SEQ Q Q_NEXT ASYNCH
GATE LOGIC1 0 O=CONST1;