Re: invalid table index
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- Subject: Re: invalid table index
- From: "Aaron Brown" <arundelo@...>
- Date: 2006年11月15日 10:25:59 -0500
Dmitriy Iassenev wrote:
if we try to assign
b[nil] = {}
then we get error 'table index is invalid', but if we try
if b[nil] == nil then
...
end
no error is raised. Is it correct behaviour?
Yes. The manual says:
An access to an indexed variable t[i] is equivalent to a
call gettable_event(t,i).
and
An assignment to an indexed variable t[i] = val is
equivalent to settable_event(t,i,val).
Both of these functions are
not defined or callable in Lua. We use [them] here only
for explanatory purposes.
Both gettable_event and settable_event use rawget to check
the current value of the table, and rawget's description
says:
index may be any value
settable_event uses rawset to do the setting, and rawset's
description says:
index [must be] any value different from nil
See also <http://lua-users.org/lists/lua-l/2006-05/msg00378.html>.
--
Aaron