The smallest unit of statement in NLP is a sentence. Each sentence is stated in terms of concepts from the underlying ontology, attributes in that ontology and named objects in capital letters. In an NLP text every sentence unambiguously compiles into a procedure call in the underlying high-level programming language such as MATLAB, Octave, SciLab, Python, etc. Symbolic languages such as Wolfram Language are capable of interpreted processing of queries by sentences. This can allow interactive requests such as that implemented in Wolfram Alpha. The difference between these and NLP is that the latter builds up a single program or a library of routines that are programmed through natural language sentences using an ontology that defines the available data structures in a high level programming language. An example text from an English language natural-language program is as follows:
If U_ is 'smc01-control', then do the following. Define surface weights Alpha as "". Initialise matrix Phi as a 'unit matrix'. Define J as the 'inertia matrix' of Spc01. Compute matrix J2 as the inverse of J. Compute position velocity error Ve and angular velocity error Oe from dynamical state X, guidance reference Xnow. Define the joint sliding surface G2 from the position velocity error Ve and angular velocity error Oe using the surface weights Alpha. Compute the smoothed sign function SG2 from the joint sliding surface G2 with sign threshold 0.01. Compute special dynamical force F from dynamical state X and surface weights Alpha. Compute control torque T and control force U from matrix J2, surface weights Alpha, special dynamical force F, smoothed sign function SG2. Finish conditional actions.
Natural-language programming is a top-down method of writing software. Its stages are as follows:
Definition of an ontology taxonomy of concepts needed to describe tasks in the topic addressed. Each concept and all their attributes are defined in natural-language words. This ontology will define the data structures the NLP can use in sentences.
Definition of one or more top-level sentences in terms of concepts from the ontology. These sentences are later used to invoke the most important activities in the topic.
Defining of each of the top-level sentences in terms of a sequence of sentences.
Defining each of the lower-level sentences in terms of other sentences or by a simple sentence of the form Execute code "...". where... stands for a code in terms of the associated high-level programming language.
Repeating the previous step until you have no sentences left undefined. During this process each of sentences can be classified to belong to a section of the document to be produced in HTML or Latex format to form the final natural-language program.
Testing the meaning of each sentence by executing its code using testing objects.
Providing a library of procedure calls which are needed in the code definitions of some low-level-sentence meanings.
Providing a title, author data and compiling the sentences into an HTML or LaTex file.
Publishing the natural-language program as a webpage on the Internet or as a PDF file compiled from the LaTex document.
Publication value of natural-language programs and documents
A natural-language program is a precise formal description of some procedure that its author created. It is human readable and it can also be read by a suitable software agent. For example, a web page in an NLP format can be read by a software personal assistant agent to a person and she or he can ask the agent to execute some sentences, i.e. carry out some task or answer a question. There is a reader agent available for English interpretation of HTML based NLP documents that a person can run on her personal computer.
Contribution of natural-language programs to machine knowledge
An ontology class in a natural-language program that is not a concept in the sense as humans use concepts. Concepts in an NLP are examples of generic human concepts. Each sentence in a natural-language program is either stating a relationship in a world model or carries out an action in the environment or carries out a computational procedure or invokes an answering mechanism in response to a question. A set of NLP sentences, with associated ontology defined, can also be used as a pseudo code that does not provide the details in any underlying high level programming language. In such an application the sentences used become high level abstractions of computing procedures that are computer language and machine independent.
