vscript debugger

[samisalreadytaken]

Adds Squirrel debugger

This is not the one that is used in Valve games, that is an old, very limited, Eclipse only debugger. This one is as extensive as possible, uses the Debug Adapter Protocol by Microsoft, a new debugger protocol standard that is already implemented by a number of editors.

Port numbers 1212 and 1213 are completely arbitrary, they can be changed. vscript_debugger_port variable is used to attach the debugger as soon as possible (but after classes are registered) for it to enable debug information for scripts loaded on map load. This only works for client though, script_debug command can't be executed while a server doesn't exist.

sqdbg_definitions.nut file is executed when the debugger attaches, this file is used to let the debugger know of the class names and how to display them in the client.

https://gist.github.com/samisalreadytaken/0e4238f501bcff21649cd2c99ae0ab2c

Ideally this would be distributed with game files, it would be too cumbersome to ask users to manually download/write this every time. It's not embedded in the binaries because it should be possible to adjust things manually.

L4D2 branch has the concommands script_connect_debugger and script_disconnect_debugger. They could replace the script_debug command to be able to disconnect the debugger on will.

Steps to test it on VS Code:

1. Download VS Code: https://code.visualstudio.com/download

2. Download and install the debugger extension: https://github.com/samisalreadytaken/sqdbg-vs/releases/download/0.1.0/sqdbg-vs-0.1.0.vsix

3. Install a Squirrel language extension from its marketplace. The one by "marcinbar" seems to work well enough.

4. Attach the debugger in game with script_debug or script_debug_client

5. Load a squirrel script in the editor, press F5, enter the connection port (1212 for server, 1213 for client)

You may now place breakpoints and use the Debug Console to execute scripts while the game is running.

This video briefly shows installation of the extension, placing line and function breakpoints, and debugging both server and client at the same time with 'compound' configurations (compounds only work for opening a folder in vscode and creating launch.json)

https://www.youtube.com/watch?v=qIxujbfh_0c

Even though VSCode is a terribly slow editor, it has (not all, but) most debugging features implemented. Other (present and future) DAP compatible editors can be used as well.

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PR Checklist

• My PR follows all guidelines in the CONTRIBUTING.md file
• My PR targets a develop branch OR targets another branch with a specific goal in mind

[Blixibon]

LGTM! This is a really powerful feature and I feel like I can only scrape the surface of what it's capable of.

I will also include sqdbg_definitions.nut in the shared content VPK.