On Wednesday, 6 June 2018 at 01:34:13 UTC, Arun Chandrasekaran
wrote:
I'm more interested in no/minimal runtime[1] than -betterC for
my use cases.
I think it will be good to have the document mention if the
function is supported without the druntime and/or with
-betterC. This documentation can be the module level or
function level. Is this possible and/or is it worth it?
I understand that using druntime function with -betterC will
make the compiler throw error. But it will be good to know it
up front via doc if a function uses druntime or not.
[1] https://dlang.org/changelog/2.079.0.html#minimal_runtime
What we actually need is to have the runtime itself to be
well-documented. In doing so, one would be able to see which
features are implemented in the runtime and which features
aren't, so what is and isn't supported in a "minimal runtime"
would be self-evident. In lew of that, however, I'll refer you
to documentation "object", "core", and "rt" here:
https://dlang.org/phobos/index.html. Another good resource is
https://wiki.dlang.org/Runtime_Hooks; it's outdated, but still
relevant.
Please also understand that one of the primary use cases for the
"minimal runtime" changes in 2.079 is to allow users to port the
runtime to a new platform incrementally in a pay-as-you-go
fashion. For that, you'll need to learn the details of the
runtime anyway.
Prior to the changes in 2.079, you had to implement a large part
of the runtime just to get a build, and most of that code would
have never even been called from your program. It was ridiculous
and a major barrier to entry. With 2.079, you can now implement
just what you need incrementally, and that will make it much
easier to learn the runtime.
What I'm trying to say, is the "minimal runtime" approach to
using D is for those who wish to become runtime hackers, and are
willing to study and experiment in order to learn how to take
control of the runtime for themselves. The reason the phrase
"minimal runtime" is often used over "no runtime" is because it
is up to you to decide which features of D to implement or not
implement.
That being said, understand that -betterC does not link in the
runtime, so anything not supported by -betterC will also not be
supported by a bare runtime. Therefore the documenation at
https://dlang.org/spec/betterc.html is still relevant to the
"minimal runtime" approach.There are differences. For
example, I think -betterC forwards asserts to the C library,
while a bare runtime would not. But, the differences are few.
You're also welcome to ask questions. I'm the one primarily
responsible for those "minimal runtime" changes, and I'd be happy
to help you if I can.
Mike
P.S. You're probably not going to have much success using Phobos
in a "minimal runtime" scenario. I'm exploring a way to get
around that at https://github.com/JinShil/utiliD.
