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Am 14.07.2016 um 10:13 schröbte Egor Skriptunoff:
On Thu, Jul 14, 2016 at 11:01 AM, Daurnimator <quae@daurnimator.com> wrote:Maybe, {1, 2, 3} for tables, @{1, 2, 3} for arrays (with array metatable applied)?In that case, why not use the already valid: S(1,2,3)Three reasons: 1) Standardization of array type in Lua (all the developers will use the same implementation of arrays) 2) Avoidance of performance penalty due to passing vararg to a function
What performance penalty? The times where Lua created an `arg` table for the vararg lists are over (which is funny, because the `arg` table is exactly what you'd want in this case) ...
And at least in bytecode table literals and function calls look surprisingly similar:
2 [5] NEWTABLE 4 3 0 3 [5] MOVE 5 0 4 [5] MOVE 6 1 5 [5] MOVE 7 2 6 [5] SETLIST 4 3 1 ; 1 7 [5] MOVE 3 4 vs. 8 [6] GETTABUP 4 0 -1 ; _ENV "f" 9 [6] MOVE 5 0 10 [6] MOVE 6 1 11 [6] MOVE 7 2 12 [6] CALL 4 4 2 13 [6] MOVE 3 4
3) Avoiding the limitation on number of function arguments
4) I can't really see Lua using one-letter functions. More idiomatic would be a `table.create` function (similar to `coroutine.create`) which is even longer than the `table.pack` we already have ... 5) It doesn't allow mixed arrays/tables, which you might want if you pass positional and keyword arguments to a function. Incidentally, that's where nil values in the array might come up as well ... `f(S( 1, 2, 3 ))` is just ugly. `f@{ 1, 2, 3 }` isn't that much better, though ...
Btw., the problem is really *empty* arrays. Lua could infer that `{ 1, 2, 3 }` is supposed to be an array and do its thing (whatever that may be), but `{}` would be ambiguous. So we only have to come up with syntax for an empty array like `{,}`, or my current favorite `{ n=0 }`. ;-)
Philipp