get drag&drop MEL script path

Save this MEL code as a .mel file.
Drag & drop it in Maya to print the path of the script.

global proc FindMe() {}
print("whatIs result -> " + `whatIs "FindMe"` + "\n");
// Mel procedure found in: C:/Folder/test.mel

Since it returns a string starting with Mel procedure found in:, we have to do some cleanup.

string $melScriptDir = `substitute "Mel procedure found in: " $melScriptPath ""`;
print($melScriptDir + "\n")
// C:/Folder/test.mel

to get the parent folder

// Remove the file name to get the parent folder ("installer.mel")
$melScriptDir = `dirname $melScriptDir`;
print($melScriptDir + "\n");
// C:/Folder/

MEL snippet