Merge signal generation and other features

[mikolasstuchlik]

This PR is WIP due to unserolved issues:

• Add inline documentation
• Add macOS to the CI and fix broken support for macOS in general

Issues addressed by this PR:

• Improvements to the Build experience and LSP Pitch: Possible improvements to the build experience. SwiftGtk#34
• Fix issues with LLDB Issues with LLDB - LLDB fails upon setting a breakpoing and crashes when executing any Swift code SwiftGtk#39
• Controversial: Implicitly marks all declarations named "priv" as if they had attribute private=1
• Prevents all "Private" records from generating unless generated in their instance record (added option -a to the main.swift file which requires all records to be genrated)
• Introduces CI
• For Class metadata types no longer generates class wrappers. Ref structs now contain static method which returnes the GType of the class and instance of the Class metatype wrapped in the Ref struct.
• Adds final class GWeak where T could be any Ref struct of a type which supports ARC. This class is a property wrapper which contains weak reference to any instance of T. This is especially beneficial for capture lists.
• Adds support for weak observation.
• Constructors and factories of GObjectInitiallyUnowned classes now consume floating reference upon initialization as adviced by the GObject documentation

Partially implemented:

• Typed signal generation. Implementation of type safe signal wrapper functions SwiftGtk#35 issues that remaining to be addressed are listed here https://github.com/mikolasstuchlik/gir2swift/pull/2 . This is due to lack of information provided by .gir signal element. Recently I have discovered, that all signals are fully described in .gir field element as callback. I am unable to take advantage of this discovery due to my deadlines.

This PR is ment for initial "quick look" into my implementation. I took the liberty to separate gir2swift files and add some directories. I also used as of yet unreleased returnBuilders.

After the PR is accepted for a review:

• update README documentation

[mikolasstuchlik]

Compatibility with macOS was restored. Working demo could be found here https://github.com/mikolasstuchlik/Matika alongside for build instructions.

There was an issue with macOS build which was resolved in a controversial manner - the issue is described here https://github.com/mikolasstuchlik/gir2swift/pull/7 in more detail.

CI passed for both lates LTS Ubuntu and macOS.

Since the issue of macOS build was addressed, the PR is no longer WIP and is officially proposed.

[rhx]

Any obstacles left for reviewing (and potentially merging) this?

[mikolasstuchlik]

Any obstacles left for reviewing (and potentially merging) this?

No, at this moment I don't plan on changing this PR in a significant way.

I look forward to a discussion about any aspect of the PR, since I have made a lot of (controversial) changes.

I plan on updating READMEs and related projects (like HelloWorld) after that (before merge).

I would like to ask you to set-up the Github Actions - the PR contains configuration file, but I apperently lack the authority to do so. The configuration in this PR requests build only at latest macOS and Ubuntu 20.04 with latest Swift and latest Gtk 3. I can add configuration for any other desired platforms.

[rhx]

Here are some initial observations:

• overall this seems to work well
• I did a quick test on macOS Catalina (as well as Big Sur) and it works fine (haven't tried different versions of Linux, but I don't expect problems as long as they run a recent version of Swift)
  • I would suggest setting up testing for at least macOS Big Sur and Catalina, the latest two Ubuntu LTS versions (and potentially other Linux distributions such as Debian, Fedora, and Arch Linux)

Some minor issues (in addition to the ones you mentioned earlier):

• The new scripts don't support spaces in directories (e.g. sources located on /Volumes/Google Drive).
  • This should be fixable by properly quoting "$PWD" and similar parameters
• Performance degradation.
  • Some operations take a very long time.
  • For example with the old config script time ./config.sh takes 0.7s on my system, while time ./run-gir2swift.sh flags -noUpdate takes 22.6 seconds.
• Extra build dependencies (jq and oniguruma)
• Some functionality missing (e.g. app-bundle.sh).

None of these are show stoppers. I'll probably merge this into a new development branch first. This gives us some more time to iron things out before unleashing everything to the greater public.