hello, i would say that if you are wanting to report errors to users, you should not use "fail" or "error". you should instead explicitly report the error. when i program i typically use "error" in situations that i think are imposible, but if there is a bug one gets a better error messeage. i don't use fail (well except sometimes implicitly in list comprahensions). the reason i avoid "fail" is that it seems hackish to me -- it implies that every monad supports errors and this should not be the case. not to mention that often the error that needs to be reported is not a string. but to answer your question, i think the motivation behind "user error", is that this is the user from the perspective of the compiler writer, i.e. the programmer. i think one should think of those errors as analogous to "segmentation fault" in C, or java's "unhandled exceptions", i.e. in a well written program the user of the program should never see them, but they can be useful to the programmers while debugging their code. David Roundy wrote:
When one triggers an exception with something like
fail "Error opening file"
The user gets a message like
Fail: user error Reason: Error opening file
which is confusing to the user, because it the user's fault. Is there some other way that it is recommended one fail? Or should I be catching userErrors at the top level and failing with my own error message?
-- ================================================== | Iavor S. Diatchki, Ph.D. student | | Department of Computer Science and Engineering | | School of OGI at OHSU | | http://www.cse.ogi.edu/~diatchki | ==================================================