This case grammar
is used to detect the agent, object and recepient in the sentence which is obtained by analysing the words with repesct to grammar of that language.
In the 1960s, Case Grammar
attempted to develop a functional sense of the parts of speech, substituting, for instance, subject with the more descriptive agent (Williams 120).
The techniques explored in the semantic phase of this work include the use of a case grammar
and frames (Schank & Abelson, 1977; Schank & Riesbeck, 1981) to map the surface structure of the text into an internal representation from which the RIFs can be formed.