Re: One time assignment to to-be-closed variiable

Alternatively:

> local x <const> = cond and db:query('select * from whatever') or db:query('select * from something else')

This is similar to the ternary operator in other languages, the only drawback being if the "then" branch is falsy then it always evaluates to the "else" branch.

If `query` returns a table type, then this might suffice here.

On Fri, 24 Sept 2021 at 07:45, Philippe Verdy <verdyp@gmail.com> wrote:

Why not:

function stat()
local function doSomething(query)
local res <const> = db:exec(query)
-- do something with res
end
if cond == 1 then
doSomething( 'select * from whatever')
else
doSomething('select * from somethingelse')
end
end
-- here the res can be <const> as you want and as well <toclose> for being closed at end of doSomething())

Or:

function stat()
local function makeQuery()
if cond == 1 then
query = 'select * from whatever'
else
query = 'select * from somethingelse'
end
end
local function doSomething(res)
-- do something with res
end
local qry <const> = makeQuery()
local res <const> = db:exec(qry)
doSomething(res)
end
-- here the res and query can both be <const>, and as well both declared <toclose> for being closed at end of stat()

Or a bit more compactly:

function stat()
local function doSomething(res)
-- do something with res
end
local qry <const> = (function()
if cond == 1 then
return 'select * from whatever'
else
return 'select * from somethingelse'
end
end)()
local res <const> = db:exec(qry)
doSomething(res)
end

Or very compactly:

function stat()
(function(res)
-- do something with res
end)(db:query((function()
if cond == 1 then
return 'select * from whatever'
else
return 'select * from somethingelse'
end
end)()))
end

Le jeu. 23 sept. 2021 à 09:48, Marc Balmer <marc@msys.ch> a écrit :
> Is it somehow possible to make one time assignment to a to-be-closed variable? E.g. something like this:
>
> local res <const>
>
> if cond == 1 then
> res = db:exec('select * from whatever')
> else
> res = db:exec('select * from somethingelse')
> end
>
> Or is it so that to-be-closed variables can only be assigned a value during creation?
>
> If the latter: It would be useful to allow for one time assignment to to-be-closed variabled.