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Posted by Shaun Biggs   USA  (644 posts)   bio
Date Tue 28 Jul 2009 02:31 AM (UTC)
Message
 Is there any way to check for a file before trying to use dofile() on it? Or, probably more usefully, is there any way to trap the error for when there is no file and do something instead of displaying something like the following?  Run-time error World: Aardwolf - Balaam Immediate execution cannot open asdf.lua: No such file or directory stack traceback: [C]: in function 'dofile' [string "Command line"]:1: in main chunk  It is much easier to fight for one's ideals than to live up to them. top

Posted by WillFa   USA  (525 posts)   bio
Date Reply #1 on Tue 28 Jul 2009 02:50 AM (UTC)
Message
 Ooooh! I came up against this one 2 or 3 weeks ago! if utils.readdir("C:\\path\\to\\file.lua") then -- do stuff. end Using ReadDir (not re-add ir, there is no infra red support ;) ) with a fully qualified file path will either return the file name, or nil if not found. top

Posted by Nick Gammon   Australia  (21,322 posts)   bio   Forum Administrator
Date Reply #2 on Tue 28 Jul 2009 03:03 AM (UTC)

Amended on Tue 28 Jul 2009 03:04 AM (UTC) by Nick Gammon

Message
 If you check out the help for dofile, it says:  Using dofile is the same as: function dofile (filename) local f = assert (loadfile (filename)) return f () end -- dofile  Thus, if you do loadfile, you will get back nil if it fails. If not, you call the resulting function (see under loadfile). So, basically:  function my_dofile (filename) local f = loadfile (filename) if not f then print "sigh -- foiled again!" return nil end -- can't load it return f () end -- my_dofile  This is more comprehensive than merely testing for the presence of the file, this checks it can be loaded (ie. it is valid Lua code). - Nick Gammon www.gammon.com.au, www.mushclient.com top

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