Thus, a language may be specified and modified within this environment, producing an environment for this language in which experiments can be performed. Klint discusses the general architecture of the environment for them, with special attention to the problem of allowing modifications in the specifications that change what has previously been done. This problem is solved by using a modular specification, in which modules are edited separately. The author describes the various parts of the system and the implementation techniques. This paper is sound, richly documented, well presented, and easy to read.
Examples illustrate the various aspects of the system.
The design and implementation choices are discussed, leading to a convincing paper. Nevertheless, some doubts remain. We discovered later that much energy had been lost in creating unnecessary languages, instead of trying to solve programming difficulties. Clearly, researchers must go on looking for more convenient languages, most of which will not reach industrial applications. It could be more efficient to build specific environments for the rare languages that reach the industrial stage.