Varieties of heuristics in sentence parsing

There are many methods of sentence parsing, but parsing always presupposes a grammar, which is usually composed of a set of so-called grammatical rules or rewriting rules. There are many grammars proposed so far, and many parsing algorithms have been developed based on these grammars. Characteristics of these parsing algorithms are a direct reflection of the features of the grammar formalisms used by sentence parsing, so that we have to clarify the basic characteristics of these grammars. We can classify grammars so far proposed into the following few classes