It's disappointing to have to do this, but I think necessary because
various issue reports have shown it to be unsound (at least as far as
inference goes) and, at the very least, confusing. This patch brings us
back to the basic rules of QTT.
On the one hand, this makes the 1 multiplicity less useful, because it
means we can't flag arguments as being used exactly once which would be
useful for optimisation purposes as well as precision in the type. On
the other hand, it removes some complexity (and a hack) from
unification, and has the advantage of being correct! Also, I still
consider the 1 multiplicity an experiment.
We can still do interesting things like protocol state tracking, which
is my primary motivation at least.
Ideally, if the 1 multiplicity is going to be more generall useful,
we'll need some kind of way of doing multiplicity polymorphism in the
future. I don't think subtyping is the way (I've pretty much always come
to regret adding some form of subtyping).
Fixes#73 (and maybe some others).
Local hints need to reduce (just like global hints do) so we expand
their definition to the lifted name before applying them.
We're identifying the global hints by knowing that the binder name is a
nested function name. This is a bit of hack, and it'd probably be better
to record that information in the binder instead, but that's a more
substantial change than I want to do right now.
This gives us the ability to define and use implementations locally, in
where clauses/local let bindings, as well as flag local definitions as
hints.
It's not yet quite equivalent to global hints, however, since it translated
the hint to a local let binding, which doesn't reduce, so if something
relies on the reduction behaviour of the hint, it won't work. This
refinement is coming later
+ Expanded the documentation on how to use literate modes.
+ Added invisible code blocks in Markdown using specially tagged comment blocks: `<!-- idris -->`.
+ Fixed OrgMode specificaton to recognise comment blocks properly.
This involves a small extension to IPragma, because to properly
elaborate names in a local scope we need to know which names are defined
in that scope so that they get applied to the environment when needed.
This means we can now define implementations of interfaces locally (but
there's still some work to do, because we don't yet have a way of
applying locally defined hints in auto search. It's coming soon!)
This is done to make able for `Data.*` modules of datatypes declared in
prelude to import modules that have their own definitions of `DecEq`
inside them (i.e. modules of datatypes declared in the `base`).
