A Techniques-based Programming Environment for Gg Odel

We describe an approach to program construction and maintenance in the declarative language GG odel. This approach combines techniques with the veriication of partial speciications. The programmer is provided with automated assistance in the enhancement of skeletons of code while being left free to complete the ne details by hand. The completed code is then veriied with respect to partial speciications to ensure that the programmer has correctly implemented their intent. This approach is illustrated with a system, intended as a part of an environment for GG odel, which employs such tools for the construction and veriication of code. We show how the facilities of GG odel-particularly its type system, control declarations and substantial system modules-make it a more advantageous language than Prolog for techniques-based program construction, and may also be exploited to good eeect in both program construction and veriication.