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- Subject: Re: Case-insensitive gsub?
- From: Edgar Toernig <froese@...>
- Date: Fri, 20 Apr 2001 04:04:00 +0200
Peter Wang wrote:
> if n then
> return gsub(s, pat, repl, n)
> return gsub(s, pat, repl)
> This might have been asked before, but why didn't you guys make
> `gsub' also accept `nil' for the final parameter?
It's because of how optional arguments in C functions are handled.
They actually check the _number_ of arguments and not whether an
argument is nil (as it is done in Lua itself).
I quote myself: [2 April 2000]
> In my opinion there's an unnecessary difference between handling
> of arguments to C functions and lua functions. A lua function
> f(a,b) cannot say if it was called via f(a,nil) or f(a). A C
> function gets either a nil or LUA_NOOBJECT for b. Why this
> difference? Isn't nil supposed to stand for "no object"? ;-)
> I think it would have been better to return nil for not passed
> arguments. The functions that check for optional arguments
> check against nil instead of LUA_NOOBJECT (then giving exactly the
> same behavior as lua functions). And an additional function (i.e
> lua_narg()) gives the real number of passed arguments to simulate
> vararg lua functions.
Sol handles arguments of C functions as proposed. The switch to 4.0
would have been the perfect time to change this API in Lua ...
PS: My old server is now longer alive. The new location of Sol is: