Add backport compatibility for non-C++17

[lars18th]

Enable backport compatibility with compilers previous to C++17.

List of changes:

• Makefile has some new checks to enable the NEED_BACKPORT flag if not C++17 support.
• New check for string_view class.
• New check for assignements of tuple class.
• Added 3rd party astring_view header only implementation.
• Some small changes for syntax compatibility.
• Using NEED_BACKPORT isolate code with incompatible code.

Tested with GCC 6.3

[lars18th]

Hi @Barracuda09 ,

Before sharing my changes related to #163 I suggest to merge this. My development environment uses an old compiler and this solves the problem to "recover" the lost compatibility with ancient platforms. I hope you agree with this solution. I feel it's clear and easy to maintain. So it doesn't need to generate troubles with your regular development. The "new" code is only enabled with the NEED_BACKPORT that is not enabled by default. My idea is time to time, check new changes and provide a fix if they will be required. All tests are done using GCC 6.3 and the program runs like a charm.

You agree? 😉

[lars18th]

Hi @Barracuda09 ,

I need to know your opinion about the backport compatibility. I have two options:

1. You don't want to include it inside the project (except some clean and small changes like PR Mini changes #167 ). Then a solution could be perhaps to provide (time to time) a PR with the required patches to compile with backport support. Then you can leave open the PR until a next version will be created. And you never merge it.
2. You want to include a minimal (and clean) backport support. Then we need to clarify wich code requires a #define to overcome any incompatibility, and which code will remains backguard compatible to overcome it.

Please, could you answer what you prefer?

Take note that with this PR all the project compiles and runs without any trouble with GCC 6.3. So my idea is to maintain almost this basic compatibility.

[Barracuda09]

Or use a patch file?

[Barracuda09]

Maybe use somethink like this?

Create patch with:
git format-patch backport --stdout > backport.patch

And apply with:
git am backport.patch

[lars18th]

Hi @Barracuda09 ,

That's the option 1. Remember that any PR can be downloaded as a patch adding ".diff" at the en of the URL. So this one is:
https://patch-diff.githubusercontent.com/raw/Barracuda09/SATPI/pull/164.diff

Therefore, if you leave the backport version X open, any user can download it and apply it. We only need to publish a simple how to in the BUILD section of the README. You agree with this then?

Anyway, I'll try to push the merge of some irrelevant and easy changes, like the proposed in #167 . Please, merge it!

[lars18th]

Hi @Barracuda09 ,

This PR is today up-to-date. Therefore, please don't close it. Any user that needs support for non-C++17 compilers can download it (with wget https://github.com/Barracuda09/SATPI/pull/164.diff) and apply it (patch -p1 < 164.diff) to create a compatible version.

I'll try in the future to check it and maintain it updated.

[Barracuda09]

Hi @lars18th

You could add something to the makefile that handles this?

[lars18th]

Hi @Barracuda09

You could add something to the makefile that handles this?

You want that the current Makefile handles this patch? That's what I've already implemented.
However, perhaps what you want is to apply the patch automatically? It's this?
Then, I need to know your opinion to this question:

• You want to add the patch to the repository (as a new file), or you want that the Makefile downloads it (as diff) from the repository?

Regards.

[Barracuda09]

I think as a diff file from the repository, that way you do not have to wait on me to add it.

Edit:
But the Makefile I can add

[lars18th]

Hi @Barracuda09 ,

To support the last changes I've created a new PR that supersedes this #173 .
You agree with the idea to close this and continue the discussion in the another onether one?

[lars18th]

Hi @Barracuda09 ,

I think as a diff file from the repository, that way you do not have to wait on me to add it.
Edit: But the Makefile I can add

So, your idea is then:

• We leave an open PR here with the changes (the advantage of a PR is that it's more easy to incorporate changes and we can trace them).
• After (time to time) we generate a backport-c11.diff file that we merge into the master repo (perhaps in a subdir called backport).
• And we modify the master Makefile to apply the patch and compile if we call to for example with make backport-c11.

You want this?

[Barracuda09]

Hi @lars18th

Yes that is exactly what I mean.

[lars18th]

Hi @Barracuda09 ,

If you will merge the PR #175 then please close this one.

[Barracuda09]

New pull request #173 does handle this