Re: Second class nil? Strong and weak nils in tables?
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- Subject: Re: Second class nil? Strong and weak nils in tables?
- From: PA <petite.abeille@...>
- Date: 2007年10月28日 09:25:36 +0100
On Oct 27, 2007, at 23:50, Duck wrote:
[This topic should be promoted to meta-thread status as it simply
refuses to die :P]
That's exactly my point. That code is the clear and natural way to use
{...}, but it also breaks whenever any of the args in ... is nil.
For reference purpose, the canonical way to enumerate variable length
arguments in 5.1 is with 'select':
for anIndex = 1, select( '#', ... ) do
local aValue = select( anIndex, ... )
-- do something with value
end
Converting a list into a table is lossy, precisely because you can't
have explicit nils in tables.
Table size needs to be recorded explicitly in that case:
local someArguments = { n = select( '#', ... ), ... }
for anIndex = 1, someArguments.n do
local aValue = someArguments[ anIndex ]
-- do something with value
end
unpack( someArguments, 1, someArguments.n )
Which looks suspiciously like the pre-5.1 way of doing things as Rici
Lake humorously pointed out:
<Digression>
If this seems like a reversion to Lua 4 and the old 'n'
field, so be it.... you could use a different key if you liked
</Digression>
http://lua-users.org/lists/lua-l/2007-06/msg00452.html