1\DOC assoc1 2 3\TYPE {assoc1 : ''a -> (''a * 'b) list -> (''a * 'b)option} 4 5\SYNOPSIS 6Searches a list of pairs for a pair whose first component equals a 7specified value. 8 9\KEYWORDS 10list. 11 12\DESCRIBE 13{assoc1 x [(x1,y1),...,(xn,yn)]} returns {SOME (xi,yi)} for the first 14pair {(xi,yi)} in the list such that {xi} equals {x}. Otherwise, {NONE} 15is returned. The lookup is done on an eqtype, i.e., the SML 16implementation must be able to decide equality for the type of {x}. 17 18\FAILURE 19Never fails. 20 21\EXAMPLE 22{ 23- assoc1 2 [(1,4),(3,2),(2,5),(2,6)]; 24> val it = SOME (2, 5) : (int * int)option 25} 26 27 28\SEEALSO 29Lib.assoc, Lib.assoc2, Lib.rev_assoc, Lib.mem, Lib.tryfind, Lib.exists, 30Lib.all. 31 32\ENDDOC 33