Add button, check playable and run at startup

[alirezanoori]

I wanted to create a new extension for VLC. I didn't know how to do these (if possible):
1. Is it possible to add a new button to VLC's interface? For instance next to "play" button.
2. How to check in a function that if a string that its value is the path to a file is a media file and can be played with VLC. For example "C:\a.mp3" should return true and "C:\a.txt" should return false.
3. Is it possible to run a function to run a script at startup? I want to create an extension that loads list of the supported files when I double click on a file and add them to the playlist so when I click the "next" button VLC jumps to the next file in the directory. Very similar to "Add similar" extension but it loads at startup and all of the supported files are added.

Best regards.

[Jean-Baptiste Kempf]

1. Not yet. But I plan to do so.
2. No, because VLC cannot know that either without trying to play the file.
3. I don't think so, but as for 1. it should be done in the future.

[alirezanoori]

Thanks for the reply.
OK. So I have to do a for loop for all the supported files. Is there anywhere that I can find list of all supported files by VLC?

[Jean-Baptiste Kempf]

include/vlc_interface.h

[alirezanoori]

Thank you.