Pyret was a pain. Error messages were not clear and the whole change > confused students. >
Can you elaborate more on this? My personal experience with Pyret is that it has an exceptionally good error message, except when an internal error occurs (which should not happen). Two language features caused us trouble, being the cause of impenetrable > bugs in student code: > > (a) Implicit begin .. end in function body. I have been writing Scheme for > 20 years, and I **didn't know this existed**, always writing begin .. end > in the very rare cases it was needed. > > Beginner Student (imho correctly) treats this as an error. I would be > happy if advanced Racket also treated it as an error. You can end up with > bizarre results if it is allowed and you don't notice what you have done. > It allows, encourages even, paranthesis errors. > Well, why do your students use `#lang racket` rather than student languages? And in my opinion, imposing students' programming environment constraints to professional programming environment is probably not a good idea. There are people who use `#lang racket` in imperative style. Forcing them to write `begin` everywhere will just cause a hassle. Pyret has this feature, by the way. > (b) Conds allowed without else. Even beginner student allows this. It > causes bugs. In htdp/universe you can end up with a void universe or a void > somewhere in univers. the error emerges a long distance in space and time > from the code that causes it. Make else clauses compulsory. > A lot of people agree with you. Here's a (pre-) RFC on the issue: https://github.com/racket/racket2-rfcs/issues/39 -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/CADcuegtY-G1Xbe34Hs7fD4Yj36%2BOX86rKVVWi%3DgLnUx54eUT6A%40mail.gmail.com.
