[m-dev.] Grade confusion

[Paul Bone]

On Mon, Nov 17, 2014 at 01:24:28AM +1100, Mark Brown wrote:
> On Sun, Nov 16, 2014 at 3:24 PM, Paul Bone <paul at bone.id.au> wrote:
> > On Sun, Nov 16, 2014 at 12:37:48PM +1100, Mark Brown wrote:
> >> On Sat, Nov 15, 2014 at 5:03 PM, Paul Bone <paul at bone.id.au> wrote:
> >> >
> >> > Hi,
> >> >
> >> > I saw this question on stackoverflow.com
> >> >
> >> > http://stackoverflow.com/questions/26916819/how-do-i-compile-for-debugging-in-mercury-programming-language/26943053#26943053
> >> >
> >> > I'm pretty sure that adding a grade flag merely adds that grade component
> >> > onto the default or specified grade.  So that if my default grade is hlc.gc
> >> > and I need to use asm_fast.gc.debug for debugging specifying --debug won't
> >> > do what I need.  In this case someone who reads the debugging part of the
> >> > user guide which instructs them to use --debug may be confused.
> >> >
> >> > A number of new users have commented on how Mercury's large number of grades
> >> > make things confusing, however that problem is going to take a long time to
> >> > solve.  In the interim, I propose changing the user guide.  Any thoughts?
> >>
> >> I have no idea what you are proposing to change the user guide to.
> >
> > Rather than simply say "mmc --debug will enable you debugging."  It should
> > say that the user should choose a debugging grade and link them to the
> > section of the manual about compilation grades.  The problem with the manual
> > as it is is that "mmc --debug" sometimes works and sometimes doesn't.
> 
> That sounds like a problem with the implementation to me. I think it
> should behave as section 7.1 suggests.

I agree, this would be best.

> 
> Does the documentation say anywhere that the --debug flag merely adds
> the .debug grade component?

Note that I'm aware.

> >
> >> The seemingly obvious solution to your problem is for the --debug
> >> option to select one of the debug grades that is actually installed,
> >> if possible. So there could be two default grades, the usual one and
> >> one with debugging. Please don't tell me you think this will take a
> >> long time to solve.
> >
> > That particular solution wouldn't take a long time technically.  It may take
> > longer for us to discuss and conclude what flags like --debug or --profiling
> > should actually do if they're no-longer grade flags.  (I have a vague
> > feeling that we discussed this recently.)
> >
> > What will take longer is solving the more general confusion that grades
> > create.  This first requires us to agree that grades are confusing and
> > create problems.
> 
> We first need to agree what problem we are discussing. The user you
> actually cited doesn't appear to be confused about grades; they're
> just wondering why --debug doesn't work the way section 7.1 suggests
> it would.

Agreed, I editorialised and assume that this problem is part of the more
general problem of having many compiliation grades which are combinations of
grade componenets.


-- 
Paul Bone