Patent US 4,956,773

According to the present invention, using a display terminal for conversation, a module structure diagram (schemata expressive of the connectional relations among respective program modules) is created, and a processing flow diagram (a kind of processing flow chart), an internal data definition diagram (schemata for specifying the formats etc. of data for use in processes) and an interface data definition diagram (schemata for specifying the formats etc. of arguments, common data between the modules, etc.) are created for each module, the created contents being stored in a memory. Further, the schematic information items of the module structure diagram, processing flow diagram, internal data definition diagram and interface data definition diagram are read out from the memory for each module and have stereotyped sentences and symbols added thereto, to generate the individual sentences of a source program. These sentences are edited according to the rules of a language, to complete the source program. If necessary, the various diagrams are printed out and utilized as program specifications.