Makes file FileOrStream the current input stream.
If there is an open input stream associated with FileOrStream, and that
stream was opened by
see/1, then it is made the current input stream;
Otherwise, the specified file is opened for input and made the current
input stream. If it is not possible to open the file,
raises an exception.
Different file names (that is, names that do not unify) represent
different streams (even if they correspond to the same file).
./food represent the same file, the
following sequence will open two streams, both connected to the same
see(food) ... see('./food')
It is important to remember to close streams when you have finished with