Normal Form

Intent

Conform sentences and clauses to a simple consistent structure, a simplified grammar.

Motivation

Responsibility-driven object-oriented software design uses a paradigm of linguistic and communication metaphors that relies on a simple statement grammar that resembles nuclear sentences.

English grammar supports a rich variety of complex expressions. However, with this richness comes the potential for ambiguity and misinterpretation. Even the nuclear sentence structure offers a great deal of variety with respect to the various grammatical aspects of nouns and verbs used in subjects, objects, and predicates.

Applicability

Use sentence normal form when

• you want to standardize the format of nuclear sentences and their clausal extensions.

Considerations

The normal form offers a simple and consistent structure with which to construct and construe English clauses and sentences. Simplicity and consistency contribute to better understanding of a subject while retaining (and sometimes revealing) essential meaning. The following table specifies the normal form for English clauses:

clause part				normal form
subject		uses		third person and singular number
		prefers		an indefinite article (a, an) to reference a single member of a class
				an indefinite pronoun (each) to reference a single member of a collection
				the definite article (the) only to reference a domain singleton
verb		uses		complete predicate with third person,
				active voice, present tense, singular number,
				affirmative polarity, and indicative mood
object		uses		third person and singular number whenever possible
		prefers		an indefinite article (a, an) to reference a single member of a class
				an indefinite pronoun (some) to reference multiple instances (of a collection or a class)
				the definite article (the) only to reference a domain singleton
preposition		used		only to complete predicates
				find appropriate verb phrases with possession discovery
conjunction		used		only for joined clauses
				correlative conjunctions may require clause summary
				but coordinate conjunctions should be separated with isolated verb or isolated subject

The following statements provides a few typical examples:

a predator captures a prey
a giver gives a gift to a recipient
a sender sends a message to a recipient through a medium
a surgeon cuts a portion from a body using a knife
a carpenter fastens a plank to a wall with a fastener (nail)

Consequences

You can organize simplified (normalized) statements by subject into a comprehensive domain vocabulary. You can also identify predicates shared by multiple subjects, and thereby discover common object responsibilities and protocols.

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