mem
Lib.mem : ''a -> ''a list -> bool
Tests whether a list contains a certain member.
An invocation mem x [x1,...,xn] returns true if some xi in the
list is equal to x. Otherwise it returns false.
Failure
Never fails.
Comments
Note that the type of the members of the list must be an SML equality type. If set operations on a non-equality type are desired, use the 'op_' variants, which take an equality predicate as an extra argument.
A high-performance implementation of finite sets may be found in
structure HOLset.
See also
Lib.op_mem, Lib.insert,
Lib.tryfind, Lib.exists,
Lib.all, Lib.assoc,
Lib.rev_assoc