1. A method of realizing, in accordance with a grammar, one or more output sequences meeting requirements specified by a generation goal, the method comprising: receiving the generation goal, wherein the generation goal incorporates semantic representation components; constructing a store of edges in accordance with the grammar, wherein: the grammar comprises a specification of any of a plurality of structured semantic representations and flat semantic representations of meanings of output sequences; constructing the store of edges in accordance with the grammar is a uniform process with respect to the plurality of structured semantic representations and flat semantic representations of meanings of output sequences; constructing the store of edges in accordance with the grammar comprises combining edges already in the store of edges, wherein: the store of edges comprises a set of incomplete edges; and the store of edges comprises a set of combinable edges, wherein: each combinable edge specifies a nonterminal specifying an overall grammatical category and meaning for the combinable edge, the nonterminal incorporating semantic representation components; the combinable edges in the store of edges are substantially the only edges specifying nonterminals that are combined with incomplete edges, in constructing the store of edges in accordance with the grammar; all nonvariable semantic representation components of the nonterminal specifying the overall grammatical category and meaning of each combinable edge have been instantiated to well-formed subexpressions of the semantic representation components of the generation goal; and extracting the output sequences meeting the requirements specified by the generation goal from the store of edges.