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Check for files
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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 (22,975 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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