Dependent typing and Refinement Typing for D
Ola Fosheim Grøstad
ola.fosheim.grostad at gmail.com
Sun Dec 22 23:37:18 UTC 2019
On Sunday, 22 December 2019 at 13:25:31 UTC, sighoya wrote:
> Yes, as I said together with constraint up propagation it
> requires SAT/SMT/Flow Typing or manual annotations, I prefer
> the latter for simplicity, it doesn't have to be perfect, even
> the upcoming overload resolution of C++ 20 isn't perfect.
Hm, C++ has only added deduction guides, nothing to do with
dependent types? Isn't that mostly a convenience feature?
> Hmm..., I have to inform myself again, I thought it is
> equivalent to solving a simplex algorithm (in linear case) but
> it doesn't seem to have an objective.
In order to speed up SMT solvers use over-approximation, so that
they don't have "trace the full behaviour of a function", but
can rather deduce that a function is always below a line (or
something else). It is an optimization. So they model types/sorts
So how you formulate the problem... can effect performance and
indeed if the problem is solved at all. That makes automation a
> Understand, but what is for more general cases like if we know
> x+y<=z for the if branch in function f and we call a function g
> in this branch requiring x^2+y^2=z^2, I think in this case we
> require an SAT/SMT.
Dataflow is usually not precise, so if you want to precise
results to overload on then you need SAT/SMT.
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