Tectogrammar

As a result of delegating the tasks of enforcing linear precedence and contiguity constraints to phenogrammar, tectogrammar's only remaining task is to guide semantic interpretation. Thus, our tectogrammatical rules do not assume any order or contiguity in their daughters. However, the formalism allows for specifying such constraints explicitly if need be. Tectogrammatical rules are represented using *->/2 infix operator. The category on the left-hand side of a tectogrammatical rule represents the mother node, and the daughters are provided (in no particular order) on the right-hand side. The daughters should be separated by commas. For example, all the following rule is specifying is that a sentence contains a NP and a VP. Nothing is said about the order of these constituents or whether they are contiguous at all.

s *--> np, vp

One may provide some conditions for the applicability of a tecto-rule much in the same manner as DCGs. The acceptable conditions are local covering, local matching, precedence, immediate precedence, local compaction and inequations or other Prolog goals. The following section discusses various structural constraints on grammar rules.