1. A method for compiling a source program comprising one or more program modules, each program module consisting of a first part which defines specifications and a second part which performs functions, said compilation method comprising steps of: detecting an encounter with a compilation phase during which a program module, not previously read, is being used while a source program is analyzed by a compiler object; interrupting the compiler object in operation in response to said detection; searching automatically for said first part of said program module in response to said detection; generating a new compiler object, and compiling said first part of said program module thus searched out automatically by the new compiler object; and resuming said compilation by said interrupted compiler object after compilation of said first part of said program module.