Re: lists with nil play nice for Lua 5.2
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- Subject: Re: lists with nil play nice for Lua 5.2
- From: Michael Roth <mroth@...>
- Date: 2007年8月07日 15:38:54 +0200
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John Belmonte schrieb:
> Common ways in which such lists are created include:
>
> { 2, nil, 'bar' } -- literal list with nil
> { f() } -- capture function return vals which include nil
> { ... } -- capture function/chunk args which include nil
The simplest solution I'm using, borrowed from FP, is:
function const(...)
local n = select("#", ...)
local t = {...}
return function() return unpack(t,1,n) end
end
So const() creates a new function which returns the original arguments.
foobar = const(1,2,3,nil,nil,nil)
print( foobar() )
Optionally, const() implemented in C can use upvalues for small numbers
of arguments and a table for large numbers of arguments.
Michael Roth
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