Structured natural language is a way of writing system requirements where the freedom of the requirements writer is limited and all requirements are written in a standard way. This approach maintains most of the expressiveness and understand-ability of natural language but ensures that some uniformity is imposed on the specification. Structured language notations use templates to specify system requirements. The specification may use programming language constructs to show alternatives and iteration, and may highlight key elements using shading or different fonts. To use a structured approach to specifying system requirements, you define one or more standard templates for requirements and represent these templates as structured forms. When a standard form is used for specifying functional requirements, the following information should be included: A description of the function or entity being specified. A description of its inputs and where these come from. A description of its outputs and where these go to. Information about the information that is needed for the computation or other entities in the system that are used (the ‘requires’ part). A description of the action to be taken. If a functional approach is used, a pre-condition setting out what must be true before the function is called, and a post-condition specifying what is true after the function is called. A description of the side effects (if any) of the operation. Using structured specifications removes some of the problems of natural language specification.
