Re: Replacing the "if" statement with an "if" expression which supersedes it

On Sat, 27 Jun 2026 at 08:16, Родион Горковенко <[email protected]> wrote:
...
> However I probably failed to clarify my question of internal statements and why I think your proposed change is really immense, not a syntactic sugar.
> Your suggested feature allows us to create new variables inside the expression, i.e. expression will affect outer scope.
> a = if x > 1 then b = 13 end
> Unless I had forgotten something or we use dirty tricks on globals table , expressions are restricted from such behavior.

The original extension was not specified nearly enough for me, and
further clarificacions were not of much help, as they began to mix
if-expressions with "(nearly) every statement is an expression", what
allows C to do a=b=1.

If you tackle it by parts, the if-expression, lets call it IF for now
to avoid collisions in the parser, is not much than adding "| IFexp"
to the or chain in exp and defining "IFexp ::= IF exp THEN exp {
ELSEIF exp THEN exp } [ ELSE exp ] end" in "The complete syntax of
lua".

In this case, as with the classic and-or, assignments will be illegal,
as they now are inside exps ( anyway, if yu were caring about the
globals table, they are already possible, "a=(x>1) and
rawset(_ENV,"b",13)", and cookedset is a one liner if you like to play
with metatables in globals.

OTOH making assignments an expression opens a real can of worms. This
would seem to need a deep change.

I like my ternaries, and would love to have them in Lua. As I would
love to have lot of other operators, like op-assign of every variety,
which I think would improve readabilty in some of the most unreadable
places of my code, as well as null coalescing or those fancy elvis
operators, but I fear powers that be want to keep Lua simple.

Francisco Olarte.

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