Re: No exceptions?

Jonathan Leffler wrote:

paul c wrote:

Bob Badour wrote:
...

The way to avoid exceptions is to treat them as compile-time errors.

I take it you really mean "ONE way to avoid exceptions ...". For one thing, I am interested in being able to express "x join y" in advance of defining a header for "x" (and I would like to evaluate it as well if that is logically possible!).

Don't forget the converse problem - there was a relation y at compile time that was removed before runtime; there's no way to generate a compile time exception for the unexceptionable, but there are not many ways of avoiding a runtime exception if the compile time y had defined attributes (was not a synonym of DEE or DUM). Obviously, you could reinterpret the entire program in the light of what you find at runtime, but then why bother with the compilation in the first place? Even within a single program, you could have a relation y available when it is first interpreted that is dropped by the time the statement referencing it is executed. So, some runtime exceptions are nigh-on unavoidable, I think.

As soon as one drops y, whatever references it must either be dropped or become unusable. Thus, as soon as one compiles a statement that references any such resource, one would get a compile-time error. Instead of generating a compile-time error when compiling some program, one would get a compile time error when one tries to invoke the program.
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