IOMode
The three modes a stream can be opened with via it.unibo.tuprolog.solve.libs.io.primitives.Open3 or it.unibo.tuprolog.solve.libs.io.primitives.Open4, mirroring the mode argument of ISO's open/3,4: READ opens an existing source for input, WRITE truncates (or creates) a sink for output, and APPEND opens (or creates) a sink for output, positioned at its end.
Each constant corresponds to the lowercase Prolog Atom with the same name (e.g. READ to read), as collected in atomValues.