map ¶This module creates a struct parameterized by the types specified in
strings key and value, mapping keys to values with a
specified default:
from map(Key=string, Value=int) access map;
map M=map(Default=-1);
M.add("z",2);
M.add("a",3);
M.add("d",4);
write(M.lookup("a"));
write(M.lookup("y"));