We present an algorithm for generating strings from logical form
encodings that improves upon previous algorithms in that it places fewer
restrictions on the class of grammars to which it is applicable. In
particular, unlike an Earley-deduction generator ,
semantically nonmonotonic grammars can be used, yet unlike top-down
methods, left-recursion is also permissible. The enabling design
feature of the algorithm is its implicit traversal of the analysis tree
for the string being generated in a semantic-head-driven fashion.