Taking this part of this message to the developers list (so as not to bias
users prematurely... I don't mind trying to bias you guys :):
> A consequence of this change is that the error message issued when an
> attempt is made to supply a non-lvalue as the left operand of assignment
> will change from
> error: illegal lvalue in assignment
> to
> error: non-lvalue actual is passed to a 'ref' formal of =
> Suggestions for further improvements in the error message would be
> welcome.
I've proposed to Tom that for the new/naive user to Chapel, the current
message seems more instructive than the latter to me. In particular, if I
write:
const x = 1;
...
x = 2;
the second message seems pretty confusing given that I may not (yet) think
of =() as being a function, may not think of it as having a formal, may
not even know what a 'ref' argument is; whereas the former is a bit more
plain/intuitive/direct. To that end, I've advocated for keeping the
status quo message as we change the =() signatures and considering
rewording/clarifications as a separate change, if at all.
If we were looking at rewording, I could easily get behind moving away
from the term 'l-value' in error message(s) like this, as I think it's
pretty technical for a typical user. In what cases would it be
wrong/misleading to say something simpler like "error: cannot assign to
const"?
I think Tom's main argument against the status quo is one of getting rid
of special cases in the compiler. I view special cases to make error
messages clearer worthwhile (And in this case, I say that knowing that
the special case is not particularly fragile or difficult to put in --
in fact, it's much easier in Tom's patch he's working on than it is
in trunk).
I think lack of special cases for error messages is why so many error
messages (ours, and in other languages) can be hard to understand, esp.
for a non-expert. Put another way, I think we should sacrifice a bit of
our time/effort in special casing error messagse if we think it will make
users more productive. In this case, I think it will.
-Brad
------------------------------------------------------------------------------
CenturyLink Cloud: The Leader in Enterprise Cloud Services.
Learn Why More Businesses Are Choosing CenturyLink Cloud For
Critical Workloads, Development Environments & Everything In Between.
Get a Quote or Start a Free Trial Today.
http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk
_______________________________________________
Chapel-developers mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/chapel-developers
