Re: write a list of variables to a file, formatted

[Philippe Lhoste <PhiLho@...>]

On 26/06/2013 21:53, Eike Decker wrote:
> As pointed out before by Thijs Schreijer, wrapping arguments into tables causes trouble
> when nil values are around. Besides, nonstring values can also be problematic with concat.
> I am not sure, but the code I wrote should handle both cases correctly.

Lua 5.2.0  Copyright (C) 1994-2011 Lua.org, PUC-Rio
> f = function () return 1, 2, nil, 3, 4 end
> print(f())
1       2       nil     3       4
> print(table.concat(table.pack(f()), " "))
stdin:1: invalid value (nil) at index 3 in table for 'concat'
stack traceback:
        [C]: in function 'concat'
        stdin:1: in main chunk
        [C]: in ?
> print(table.concat({ f() }, " "))
stdin:1: invalid value (nil) at index 3 in table for 'concat'
stack traceback:
        [C]: in function 'concat'
        stdin:1: in main chunk
        [C]: in ?

Non-string values are fine, but nil is indeed a showstopper...
Your wrapper, Eike, takes care nicely of the problem (and nil can be ignored or changed to 
something specific, too).

Note that print() doesn't separate with spaces but with tabs.

--
Philippe Lhoste
--  (near) Paris -- France
--  http://Phi.Lho.free.fr
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