Re: lists with nil play nice for Lua 5.2

[PA <petite.abeille@...>]

On Aug 01, 2007, at 13:30, Roberto Ierusalimschy wrote:

> Another option is to implement tuples. We can implement them as C
> functions with upvalues (PiL2, p. 257). With a few extra lines of code,
> we get the following:
>
>   a = new.tuple(2, nil, "foo")
>   #a   -- not available; perhaps a"#" ???
>   a:insert("baz")   -- not available (tuples are immutable)
>   a(3)    -- yields "foo"
>   a()     -- yields 2, nil, "foo"
>   for i, v in a do ...    -- or something like this...

Here is a straight Lua implementation of sort:

local Tuple = require( 'Tuple' )
local aTuple = Tuple( 2, nil, 'foo', nil )

print( #aTuple )
print( aTuple( 3 ) )

for anIndex, aValue in aTuple do
    print( anIndex, aValue )
end

> 4
> foo
> 1       2
> 2       nil
> 3       foo
> 4       nil

Attachment: Tuple.lua
Description: Binary data