hi guys, i take basic example from http://lua-users.org/wiki/ControlStructureTutorial
Code:

if 1>10 then print("bigger") else print("smaller") end 

post it into LUA script and it doe snot work.
I post it into LUA expression evaluator , and it says [Syntax error at char [4]!]

Thanks for hint with arrow! drop down list looks inviting, but does not work
 
And thanks, this work now with your help.
 
This is a basic function that sets a key number to the ItemKeyNumber folder.
If key number was set already, it leaves it intact.
If it was not set, it makes it max+1.
 
This can be useful when you export your items somewhere, eg to excel, and want to have a specific key to identify items. For example if you make pivots and summarize costs by another columns, or draw graphs.
 
Code:

function setnewkey()
curentvalue = 0 + ("0" .. get_folder_value("ItemKeyNumber",get_select_items()[1]) )   --- leave current value as is, or set it = 0, but not leave NULL.
if curentvalue ==0 then				  --- then set curentvalue = max+1
	x = get_folder_items("ItemKeyNumber")   
	max=table.maxn(x) 
	m=0
		for i=1,max do				--- discover what is the max
		m = math.max(m, get_folder_value("ItemKeyNumber",x[i]) )
		end
	set_folder_value("ItemKeyNumber",get_select_items()[1],m+1) 
end
end