DIP 1025--Dynamic Arrays Only Shrink, Never Grow--Community Review Round 1
Ola Fosheim Grøstad
ola.fosheim.grostad at gmail.com
Tue Nov 12 11:57:12 UTC 2019
On Tuesday, 12 November 2019 at 11:12:30 UTC, Jonathan M Davis
> Dynamic arrays and manually managed memory are a _terrible_
> combination, because dynamic arrays do nothing to manage
> lifetimes. They're really not any different from passing naked
> pointers around as far as lifetime tracking goes. This means
> that the only way that you can automatically manage that is to
> restrict where they can be stored. scope does that, but the
> result is that you can pretty much just pass the data into a
> function that operates on it and doesn't store it.
One option, albeit unorthodox, is to require heap-stored slices
to be "concrete" and therefore "encode" the properties of what it
Whereas you could allow slices used in the call-graph to be
"abstract" (templated, but without the syntax) and then infer
their concrete properties using static analysis.
So, the counter-argument would be "combinatorial explosion", but
if the compiler deduce that the actual function that is being
compiled generate the same code for a set of concrete slice types
then you can emit a single copy of the compiled code.
Anyway, that ought to be sufficient to distinguish GC, reference
counted and RAII objects. And it would also allow D slices to
differ from C++ slices, but also allow you to write one function
to cover both scenarios.
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