In this article we propose a semi-automatic generator of self-assessment exercises. This work is part of the CLAIRE project the aim of which is to design a collaborative authoring platform for pedagogic content. The proposed generator of exercises allows the author (usually a teacher) to create a model of exercise according to his/her pedagogic objectives. This model is automatically instantiated to produce several different exercises that evaluate the same skills. The learner's answer is automatically and instantly evaluated by the system. He/she thus receives immediate feedback on his/her skills. The distinctive feature of this generator is that the proposed types of exercise are independent of the domain, which allows them to be used for many different subjects and levels. In addition, domain knowledge is used to facilitate the author's task when the model of exercises and the diagnostic are designed.