Hi,
you can simply write it like this (excerpt from install.bat):
reg add "HKCU\Software\Classes\luafile\shell\open\command" /ve /d "\"%~dp0bin\luart.exe\" \"%%1\" %%*" /f >NUL
Mind the %%* at the end of the command.
I would suggest to add it to both commands, just like any other script interpreter does (look at Python after installation).
As an example: you have an editor written using the ui module, but it is not convinient to always run the script and select File->Open from the menu just to read some text file. Calling something like MyEditor.wlua "C:\Temp\test.txt" is much easier.
On my system i added .lua and .wlua to my %PATHEXT% environment variable, so that i can run my scripts directly by just typing the name in the commandline. Without these %%* that wouldn't be possible.
Greetings
