After successful completion of the course, students are able to

• list reasons for the use of types in programming languages,
• describe different kinds of types in programming languages,
• roughly outline formal rule systems used by compilers for type checking,
• compare different kinds of types concerning their most important prospects and limits.

• meaning of the notion of type in programming languages
• classification of programming languages regarding type systems
• simple theoretical type models
• types in imperative languages (especially Ada)
• theoretical models of polymorphic type systems and type inference
• programming languages with polymorphic type systems
• subtyping
• genericity
• types as partial specifications of object behariour
• use of polymorphic type systems in object-oriented programming
• current trends

"Typesystems" is a lecture in a classic style based on a weekly talk (online because of Corona regulations), mixed up by activities like interposed questions and brief discussions. After an overview and the introduction of some terminology we repeatedly examine (1) practical experiences, (2) formal models based on them and (3) typical applications thereof for type checking, leading to new practical experiences. Students shall prepare themselves for the talks and the final exam also by autonomous research (supported by the script).

For online lectures we use Zoom. You will find access data necessary to participate in lectures (as well as a script and slides) in TUWEL. Please register for this course early enough in TISS because you will get access to TUWEL only after registration.

ECTS-Breakdown:

• 25h: Participation in online lectures
• 25h: Consolitation of the topics by autonomous research
• 25h: Preparation for exam and oral exam

An online exam will check the learning outcomes given above. As soon as the Corona situation allow us to do so in general, online exams can be replaced by usual oral presence exams. For online exams we use Zoom. These are the conditions:

• Appointment and registration are arranged by mail. In general, there will be exams each Monday (except during holidays) from 10 a.m. to 11 a.m., but can also be arranged at other times. Registrations must be made at least 14 days before the exams. It is possible to unregister until the exam starts.
• A link to the Zoom-Meeting used for exams will be accessible through TUWEL. You need a computer (e.g., laptop) with microphone and video cam. Please take care that your browser (Chrome only) or the Zoom software have the right to access microphone and cam. Enter the Zoom session at the time the exam is scheduled for (see https://colab.tuwien.ac.at/pages/viewpage.action?pageId=11634937).
• Use a room for the exam where you are undisturbed. Close to your working place there can only be objects that are allowed to be in front of you also in usual oral exams (e.g., ID card, white paper, pen, water glas) as well as technical equipment used for the exam, but nothing else (especially no cell phone and text book). Further away from you there can be anything. However, there must not be other persons in the room.
• If you want to invite another person as a witness to the exam, you can give your access data for the Zoom meeting to them. This person shall enter the meeting at about the same time as you. Please inform the lecturer at the begin of the exam about the invitation of a witness in order to ensure that nobody enters the session during the exam. Examinee and lecturer can each invite at most one witness to avoid unnecessary complexity. Microphones and cams of witnesses shall be switched off.
• At the begin of the exam you are asked to show your ID card (preferably Studierendenausweis) and your room (by moving around your cam or laptop).
• You have to answer questions. However, we have to expect that the audio and video quality is far away from being perfect. The gesture may not be identifiable. Therefore, it may be necessary to repeat questions and answers as well as to ask additional questions. Please be prepared that the exam may last longer than expected for such reasons.
• If a question was not understandable because of bad audio or video quality, please ask to repeat it. If the connection is lost, please enter the Zoom meeting again using the same access data as before. If that does not work, please contact the lecturer by mail. In that case the exam will be continued at a later time according to new arrangements.
• There are no recordings of video or audio. If you want to record the exam, it is necessary to have a written bilateral commitment about that in advance (by mail). Otherwise recordings are prohibited.
• If circumstances indicate that online exams are inappropriate to check learning outcomes, you can take a usual oral presence exam instead provided that this is possible under Corona constraints. In the same way it is possible to continue an interrupted online exam as an oral presence exam.

Find the script and the slides (all in German) in TUWEL.

Students are expected to have good practical programming capabilities in strongly typed object-oriented (and in the ideal case also functional) programming languages; this implies experience in the static use of types.