[m-dev.] diff: changes to term_to_type & type_to_term

[Fergus Henderson]

Thomas Charles CONWAY, you wrote:
> > library/term.m:
> > 	- Improve the error messages available from term_to_type: add
> > 	  a new predicate `try_term_to_type' which is like term_to_type
> > 	  but which returns much more detailed information rather than
> > 	  failing.  (XXX not yet done: we should modify io__read to take
> > 	  advantage of this.)
> 
> This looks good.
> Should io__read give back a term_to_type_result?

I think it should just give back a string and a term__context.
Giving back a term_to_type_result would burden the user of io__read
with the responsibility of handling all the different possible
errors.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>   |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>   |  of excellence is a lethal habit"
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