It is possible to override the MapScript.galaxy file, but opening the trigger editor and saving your map would probably recompile it back to it's blank state. And it is definitely possible to script entirely in galaxy.
I believe the function called upon map initialization is InitMap, which initializes all libraries, triggers, events and custom scripts. Can't help you confirm it now as I don't have access to my editor, but pressing Ctrl+F11 on a new map should make it clear where the starting point is since you're familiar with script.
Thus, to script in pure galaxy, on Notepad+ + or what not, you'd just have to use InitMap as your starting function and work from there.
Edit: Welcome to the scripting club :) We're a rare breed over here.
It is possible to override the MapScript.galaxy file, but opening the trigger editor and saving your map would probably recompile it back to it's blank state. And it is definitely possible to script entirely in galaxy.
I believe the function called upon map initialization is InitMap, which initializes all libraries, triggers, events and custom scripts. Can't help you confirm it now as I don't have access to my editor, but pressing Ctrl+F11 on a new map should make it clear where the starting point is since you're familiar with script.
Thus, to script in pure galaxy, on Notepad+ + or what not, you'd just have to use InitMap as your starting function and work from there.
Edit: Welcome to the scripting club :) We're a rare breed over here.