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From Paul King <>
Subject Re: fin
Date Sun, 22 Jul 2018 06:53:03 GMT
I am probably -1 right now on a new keyword when I think the existing one
works just fine.

One reason some Groovy folks might not use final more frequently is because
it has
historically (up until 2.4.x) been ignored by Groovy for local variables.
also ignores final at runtime for local variables but that doesn't matter
for a statically
compiled language. Have a look at the bytecode using javap -v from this
Java program:

public class Hello {
public void method1() {
final Object o1 = new Object();
public void method2() {
Object o2 = new Object();

You will notice that the bytecode for method1 and method2 is identical.
Groovy 2.5 does a better job of detecting final for local variables. It
does it
in a similar sort of way to Java - at compile time. I'd be inclined to wait
see how this added support (plus @AutoFinal) affects usage.

The other discussions I have seen around not using final are around style.
The 'final' modifier is particularly good at stopping the practice of
mutating some
variable mid-way through a long method in a confusing way. Agile practices
discourage long methods, functional style discourages mutating variables
and codenarc can be used to some extent to catch bad behavior. So some
advocate omitting the final keyword but coding as if it was there to obtain
more succinct, easier to read code. Now that we have @AutoFinal, I am
not sure that we need to aggressively further promote its usage but rather
watch how usage changes in the short term.

Cheers, Paul.

On Sun, Jul 22, 2018 at 7:50 AM MG <> wrote:

> Hi guys,
> I have been wondering for a while whether Groovy developers use "def"
> even if a variable is actually is "final" not only because every Groovy
> example code uses "def", but also because "final" as a word is longer
> than "def".
> Therefore I propose to introduce the shortcut "fin" for "final" in Groovy.
> e.g. to support
> class Goo {
>      fin String name
>      fin Goo gooParent
>      Goo(fin String name, fin Goo gooParent) { ... }
>      String gooGoal(fin x) {
>          fin y = 2*x
>          fin int z = x + y
>      }
> }
> Cheers,
> mg

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