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

On Sat, 27 Jun 2026 at 19:29, Lan Krownet <[email protected]> wrote:
>
> Operator assignment is not necessarily the only way to do it, because the issue assignment operators are trying to solve is not having to retype a really long variable, well, you could have a single unary prefix operator with a number that basically takes the variable being assigned in the expression and pastes it into the code like

IMO the retyping is not the problem.

> areallylongvariable = $0+1
> turns into
> areallylongvariable = areallylongvariable+1

This is some kind of preprocessor trick. Useful, but there are things like:
f(a).x.g(b)[h(d+e)]*=2 where, due to potential side effects, you can
not use it. And even without them you will hit a runtime penalty. I
mean, in lua you cannot substitute a.b.c.d=a.b.c.d+1 with do local x =
a.b.c x.d=x.d+1 end. So that rules out the preprocessor tricks and
either imposes a runtime penalty or forces you to exactly define the
semantics. In fact I fear this need is one of the arguments for not
having op-assign. In C, where you have addresses, it is easier as you
can define x+=1 as y=&x; *y=*y+1. But in lua = is a complex beast.

Besides, coming from old assemblers, and C/C++/perl, I've found a+=7
is a more fundamental op than a=a+7, I'm used to do think on it as
"add a,1" and "add_and_store a,b,1". In fact when you overload
operators in C++ you normally do it that way.

> or it could point to any section, which is nice when you just want to swap some variables
> var1, var2 = $2, $1 -- variables are swapped
Once you "preprocess" you can also macro that, that is why I like
having preprocessors. You do not use much but when you have half a
page of swaps they are nice and let you give names to things without
cost. But I'm disegressing, so lets sign out.

Francisco Olarte.

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