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.
CACM April, 1967
Brooker, R. A.
