[m-rev.] for review: better error messages for lambda exprs

[Mark Brown]

Hi,

On Tue, May 17, 2016 at 10:10 AM, Julien Fischer <jfischer at opturion.com> wrote:
>
> On Tue, 17 May 2016, Mark Brown wrote:
>
>>> +    ; Name = "or"                   % goal
>>> +    ; Name = "and"                  % goal
>>> +    ; Name = "try"                  % goal
>>> +    ; Name = "@"                    % goal
>>> +    ; Name = "true"                 % goal
>>> +    ; Name = "fail"                 % goal
>>
>>
>> Okay.
>
>
> "or" and "and" are both currently used as predicate / function
> names by the bool module.

Yes, but there can be module based exceptions for such things.

For the builtin types, you're probably right: there's generally not
much potential for a parser to get confused by names that are not
operators. For >> and =< you're also probably right: with the other
keywords in place, we should always be able to tell whether we're
trying to parse an inst or mode.

I'm trying to come up with a good set of rules that will tell us what
should be a keyword. Something more concrete than just saying it's
hard to produce good errors.

>
>>> +    ; Name = "with_type"            % goal
>
>
> I'd be happy to (eventually) remove "with_type" in favour
> of ":".
>
>>> +    ; Name = "with_inst"            % goal
>>
>>
>> I'd rather deprecate these as significant.
>
>
> What do you mean by that?  (There isn't a replacment
> for "with_inst" is there?)

No, but weren't we going to come up with one? Can '::' be used?

Mark