import()

[meia-lua]

Hello,

Is there no documentation on import() as far as I remember this isn't part of Lua.

Thanks.

[cassius]

Don't you just put import"filename" ?

[meia-lua]

Well yes but what happens if the same file is imported from multiple points in your application,

For example if I have 3 scripts 'util.lua', 'math.lua' and 'main.lua'. In main.lua I import both 'ulti.lua' and 'math.lua' and in 'math.lua' I import 'util.lua'. I would have thought this sort of thing would be documented. 

 

[AggrorJorn]

I recall that when you import a file a second time, it is ignored since you have already loaded that file. This is stored internally in a cache somewhere.

[Rick]

It loads each time it sees an import but since you're importing the same thing (and generally it's definitions of functions and tables) it generally doesn't matter as the result is the same. If you want to avoid this you can do checks up front if something is defined or not to determine to do the rest of the script.

 

util.lua

if _UTIL_ ~= nil then return end

-- define util so we only will define the util stuff once even if there are multiple imports of it
_UTIL_ = {}

--define util functions here

 

[Josh]

import will work with the zip file system when you game is exported. Lua Include won't.

It should only execute each imported file the first time it is imported by any file.

[meia-lua]

Thank you all.