(DIRFT) A programming approach that aims to avoid the overheads of debugging and testing incomplete or incorrect code by careful specification, design and implementation. DIRFT contrasts with rapid prototyping which emphasises the benefits of having running code as soon as possible, even if it is not perfect. DIRFT is appropriate in the rare cases where the requirements are well understood and unlikely to change, e.g. reimplementing exactly the same function in a different language.