Many systems require the encoding of knowledge in some kind of logical formalism. Normally this task has to be entrusted to knowledge engineers who are specialists in a knowledge representation language; thus expert systems (for example) require a collaboration between a domain expert (who knows about the subject matter) and a knowledge engineer (who knows about the knowledge formalism).
WYSIWYM aims to allow domain experts to encode their knowledge directly, by interacting with a feedback text, generated by the system, which presents the knowledge defined so far and the options for extending or revising it. Previous knowledge editors have provided a graphical interface so that users can interact with diagrams rather than writing code; WYSIWYM takes a step further, exploiting automatic text generation so that the user interacts with an ordinary natural language document rather than a relatively unfamiliar diagram.
The acronym means `What You See Is What You Meant'. The feedback text presented to the user (What You See) reveals the knowledge that has been encoded during the interaction so far (What You Meant). Documentation of knowledge bases becomes automatic, since the system is designed to produce a description in natural language of any knowledge base in any state of completion. The only limitation is that the knowledge base must conform to an ontology which from the user's point of view is fixed. If this ontology proves insufficient, it must be extended by a programmer; the user cannot add new concepts because the system would lack the linguistic resources to express them.