6.1.4 Implementation Implementation is concerned with transforming a design into a working software product. If good design practice has been followed, the design inmost cases should not be platform-specific, even if it is not explicitly portable. In most cases, the implementation targets one specific environment. Occasionally, versions for multiple environments are implemented simultaneously. During portable development, it is also possible to envision an implementation that has no specific target, but is ready for porting to many environments. Developers who strive for portability most frequently concentrate their attention on the implementation phase, so the issues here are fairly well understood. We offer three guidelines: Choose a portable language. If the language or languages to be used were not determined by the design phase, thy must be chosen now. Many factors go into good language choice, including programmer experience, availability of tools, suitability for the application domain, etc. An additional factor should be considered is the language well standardized, widely implemented, and thus a good choice for portability? Follow a portability discipline. It is not enough to select a good language the language should be used in a disciplined way. Every language has features that are likely to be portability problems. Any compiler features that check for portability should be enabled. Understand and follow the standards. The design phase and language choice have identified standards for use. The programmer must study and understand those standards, to be sure that the implementation actually matches what the standard says, and what will be expected on the other side of the interface. 1. 2. 3.
