std.range.constraints & std.array code/import swap

[9il]

The goal of this PR is to prevent import std.array, std.functional and std.algorithm through std.range.constraints.

1. clean imports in std.array
2. move some common code into std.range.constraints. The reason is optimisation of compilation time.

Note:

1. std.array imports std.functional and std.algorithm in global scope. See std.array.splitter.
2. std.range.constraints is going to be common global import for half of phobos instead of std.range.

See also: #2700 #2661 Issue 13253 - use more scoped imports in phobos

[quickfur]

I'm unsure about putting array range primitives in std.range.constraints. Array range primitives are not constraints, and std.range.constraints is growing to include lots of other non-constraint stuff. Maybe we should rename it to std.range.primitives instead, or maybe make that a separate submodule of std.range?

[9il]

Both range and array primitives should be imported into std.range.constraints because is* and has* use primitives.
If you use std.range.constraints you would use primitives (98%).
std.array globally include std.range.constraints anyway.

So I think this PR is good. It also do not break any code.

[DmitryOlshansky]

@quickfur The name is unfortunate but let's not dwell on that. Think of it as core or minimal.

[DmitryOlshansky]

LGTM

[DmitryOlshansky]

@9il Would be cool to see some stats on build times. I'll collect some on my own when time permits but if you did such measures would be nice to share them.

[9il]

@DmitryOlshansky I know how to build dmd with Digger manager. How can do this with my local repo?

[DmitryOlshansky]

@9il technically Digger should accept old pull numbers and hashes of commits as well?

But anyway:

git checkout <hash of some commit before your pulls>
make -f posix.mak
time make -f posix.mak unittest

#then back to master
git checkout master
make -f posix.mak
time make -f posix.mak unittest

[9il]

I think test with unittest will have the same time because:

1. Files in posix.mak are grouped into few parts.
2. unittest version of code often imports half of phobos.

[9il]

This stuff should be compiled faster with PR.
time dmd -main test.d

import std.range.constraints;

auto foo(Range, E)(Range r, E e) if(isInputRange!Range)
{
    while(!r.empty && r.front != e)
        r.popFront;
    return r;
}

alias bar = foo!(uint[], uint);

[DmitryOlshansky]

All in all things seem to improve, or at least not regress.

a728319f8bbae9a2b57d0d4fd6133bc3d66d4d75:
time make -f posix.mak
real    0m11.299s
user    0m9.077s
sys 0m2.109s
real    0m11.376s
user    0m9.137s
sys 0m2.108s

unittest
real    2m33.675s
user    2m6.192s
sys 0m26.322s

master:

time make -f posix.mak
real    0m11.171s
user    0m8.994s
sys 0m2.066s

real    0m11.376s
user    0m9.119s
sys 0m2.116s

unittest
real    2m29.171s
user    2m3.104s
sys 0m25.652s

[DmitryOlshansky]

Aaand your test case, before this pull:

dmitry@Ubu64 ~/dmd2/src/phobos $ time dmd -main testing.d 

real    0m0.234s
user    0m0.132s
sys 0m0.065s
dmitry@Ubu64 ~/dmd2/src/phobos $ time dmd -main testing.d 

real    0m0.211s
user    0m0.132s
sys 0m0.065s

After:

dmitry@Ubu64 ~/dmd2/src/phobos $ time dmd -main testing.d 

real    0m0.187s
user    0m0.108s
sys 0m0.054s
dmitry@Ubu64 ~/dmd2/src/phobos $ time dmd -main testing.d 

real    0m0.165s
user    0m0.111s
sys 0m0.054s
dmitry@Ubu64 ~/dmd2/src/phobos $ time dmd -main testing.d 

real    0m0.167s
user    0m0.112s
sys 0m0.052s

[9il]

@DmitryOlshansky Thanks!

[quickfur]

Anything else to address? Are we ready to merge?

[quickfur]

P.S. Regarding the naming of std.range.constraints, it doesn't directly concern this PR, so it doesn't need to block this PR, but we do need to seriously consider a proper name for it before the next release. We can still rename it now without major problems, but once it makes it into an official release, it's going to be much harder to change things. So we better think very carefully now what name we want to use, while it's still relatively easy to change.

[9il]

Yes, I ready)

[9il]

@quickfur Please take under control the question about module name and discus it with other collaborators.

[quickfur]

Maybe we should bring it up in the forum?

[quickfur]

Auto-merge toggled on

[9il]

@quickfur At your convenience (about forum).