[m-dev.] syntax proposals

[Ralph Becket]

Fergus Henderson, Friday, 16 November 2001:
> On 07-Nov-2001, Ralph Becket <rafe at cs.mu.OZ.AU> wrote:
> > One thing that I find aesthetically distressing is that we currently
> > have different syntax for declarations at the top-level and for nested
> > declarations such as with typeclass and instances.
> > 
> > This stems from using lists to group nested declarations and
> > definitions.  Can we introduce a different kind of `list' for this
> > purpose which perserves the top-level syntax.
> 
> That would be techically feasible, yes.
> 
> One complication would be that the parser might have to
> do a smarter job of error recovery.  Currently we just
> use the very simple algorithm of skipping to the next
> item, but once you have significant nesting outside the
> items, then that strategy can lead to a whole swathe of
> spurious errors if e.g. a nesting terminator is accidentally
> omitted.
> 
> Of course, we have that problem with nested modules already.

True - this sort of thing usually leads to an "infinite string of
errors" which many programmer's will recognise as an indication of a
missing terminator.

- Ralph
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