1612	 Top-to-bottom Parsing Rehabilitated	 This note is concerned with the efficiency of the Top-to-Bottom parsing algorithm as used in connection with programming language grammars. It is shown for instance that retracing of unprofitable paths can often be eliminated by a suitable rearrangement of the productions defining the grammar. The essential weakness of the method is in dealing with complicated syntactic structures which are in practice only sparsely occupied e.g. arithmetic expressions.
