[m-rev.] the grade library is ready for review

[Zoltan Somogyi]

On Tue, 05 Apr 2016 00:37:24 +1000 (AEST), "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
> >     $ ./choose_grade ssdebug=ssdebug tscope_prof=tscope_prof 
> >     Uncaught Mercury exception:
> >     Software Error: predicate
> >     `grade_lib.grade_solver.accumulate_why_var_is_not_values'/5: Unexpected:
> >     is_possible
> >     Stack dump not available in this grade.
> 
> That is an expected failure: tscope requires LLDS, but ssdebug
> does not make sense in LLDS grades, since the C debugger is
> significantly better.
> 
> The problem you found is in how the failure is presented: it should
> generate an error message, not a stack dump. I will fix it.

I have now fixed it. The output is now:

$ ./choose_grade ssdebug=ssdebug tscope_prof=tscope_prof
FAILURE
Source-to-source debugging does not make sense for the LLDS backend.
    The variable backend may not be mlds because: Threadscope style profiling requires the LLDS backend.
    The variable backend may not be elds because: Threadscope style profiling requires the LLDS backend.

The presentation can be improved, but this part of the grade library
will have to be redone anyway when the library is called from the
compiler, since the compiler will use error_util.m to format error messages.

> For something this important, I would prefer to have two or three reviews,
> though it may be a good idea for other reviews to look at the grade library
> after I fixed the issues raised by Paul.

This has now happened.

Zoltan.