Re: [ANN] Lua 5.4.0 (alpha-rc2) now available

[Daurnimator <quae@...>]

On Tue, 11 Jun 2019 at 23:11, Luiz Henrique de Figueiredo
<lhf@tecgraf.puc-rio.br> wrote:
> Lua 5.4.0 (alpha) will be frozen very soon.
>
> All feedback welcome. Thanks.

I've stayed quiet so far as I've been waiting for the new syntax to grow on me.
However... I can't say it has yet.

  - local <const> feels awkward for what should almost be the default
variable type
    I see myself wanting to have const variables far more than plain
locals, which
    suggests that a *shorter* syntax would be preferable. Several
other languages
    have gone with simply `const` (which would replace "local" when
you want to make
    a modifiable varible; rather than as a qualifier/attribute)

do
    const x = 1
    local y = 2
    x = "something else" -- error: attempt to assign to const variable
end

  - Similarly other languages have `defer` as a similar concept to
"toclose": to try and
    shoehorn it into lua: a defer block could run when the current
lexical scope finishes:

local contents
do
    local f = io.open("myfile")
    defer f:close() end
    contents = f:read()
end

  - To response to Hisham's suggestion of variable annotations, I do
like the idea;
     however I don't think that const nor toclose match what I expect
from annotations.

  - I'm unsatisfied with the response to Andrew Gierth's comment about
ensuring that
    errors are propagated to the embedder: I think it's crucial to
lua's use as an
    embeddable language
    I *think* the solution should be that an error in a <toclose>
should be immediately rethrown
    and that other <toclose> statements don't get to run.

  - Now that lua_gc is a vararg, perhaps LUA_GCCOUNTB could be deprecated?
    (instead have a single COUNT opcode that receives two out-args?)

  - Could we add a shared library target to the Makefile? I think this
is a reasonable patch:
    https://git.archlinux.org/svntogit/packages.git/tree/trunk/liblua.so.patch?h=packages/lua