libgre-plugin-lua.so

Additional arguments can be passed to the function by providing additional key/value pairs to the action. The key/value pairs are provided to the Lua function as values in the argument table.

For example to call the Lua function myfunction with an extra argument, firstargument, that corresponds to the value of the application variable myvar you would simply add a new entry to the parameter list.

The corresponding call to the Lua function would fill the entry into the argument table such that:

function myfunction(mapargs)
    print("The value is: " .. tostring(mapargs.firstargument))
end
                    

would print out the value of ${app:myvar}.