Java supports `var` only for local variable declarations when it can infer
the type from the expression on the right side of '='
Gianluca Sartori
--
Cell. +39 388 1026822
On Thu, 21 Nov 2024 at 19:17, Steve Etchelecu <steve.etchel...@gmail.com>
wrote:
> I thought Gianluca made an excellent argument and helps modernize the
> language. Given Groovy’s symbiotic relationship with Java, it seems like
> the guidance here should probably be to follow Java’s usage as that likely
> keeps friction/confusion to a minimum.
>
> Not being a Java developer, it isn’t clear to me whether Java supports var
> as a return type though I assume it does for consistency.
>
> On Nov 21, 2024, at 11:10, Milles, Eric (TR Technology) via dev <
> dev@groovy.apache.org> wrote:
>
>
> I don't think semantically that "var name() { ... }" makes sense.
>
> One might argue that var for field and property do not make sense either.
> We could explore removing support for var on class members.
> ------------------------------
> *From:* Gianluca Sartori <g.sart...@gmail.com>
> *Sent:* Thursday, November 21, 2024 10:57 AM
> *To:* dev@groovy.apache.org <dev@groovy.apache.org>
> *Subject:* [EXT] Re: Using `var` as method return type placeholder
>
> *External Email:* Use caution with links and attachments.
> Well, actually that's not true, Groovy supports creating fields and
> properties as well with `var`, so basically everything `def` does
> except return types.
>
>
> Gianluca Sartori
> --
> Cell. +39 388 1026822
>
>
> On Thu, 21 Nov 2024 at 17:41, Daniel Sun <sun...@apache.org> wrote:
>
> Hi Gianluca,
>
> `var` was introduced to Groovy just for the better compatibility of
> Java. Java just supports declaring variables with `var`, so does Groovy.
>
> Cheers,
> Daniel Sun
>
> On 2024/11/21 10:37:23 Gianluca Sartori wrote:
> > Hello everybody,
> >
> > My name is Gianluca Sartori, from Italy, I am the author of the open
> source
> > project Dueuno Elements (
> https://github.com/dueuno-projects/dueuno-elements
> <https://urldefense.com/v3/__https://github.com/dueuno-projects/dueuno-elements__;!!GFN0sa3rsbfR8OLyAw!dKLiRGGSN06yuMZYXThMMGLu5ES8nh1240B7mX97feXlJsWHlparG8WQWaFKj2SCDpw5PVXgiTa1KWx0GZNXc3SM$>
> )
> > and I am new to this list.
> >
> > I would like to start using the more Java-ish `var` instead of the
> > Python-ish `def` lexicon but I came across the fact that I cannot use
> `var`
> > as method return type placeholder.
> >
> > My understanding is that I can use `var` for both local variables and
> class
> > fields/properties but I cannot use it, for example, if I want to have a
> > read only property. The code below does not compile:
> >
> > class C {
> > var firstname
> > var lastname
> >
> > var getFullname() {
> > return firstname + ' ' + lastname
> > }
> > }
> >
> > var c = new C(firstname: 'Gianluca', lastname: 'Sartori')
> > c.fullname
> >
> > I'd like to switch to using `var` as a type placeholder, but having to
> use
> > `var` for variable declaration and keep using `def` for methods
> definition
> > is something I don't understand. I love Groovy because it is easy. This
> > restriction of the `var` type placeholder forces me to write code that
> > mixes Python lexicon the new Java lexicon.
> >
> > My main worry is with Grails controllers where we need to define an
> action
> > using `def` (or `Object`) as return type and define variables in the
> method
> > body. At the moment we have the following options:
> >
> > *def* index() {
> > *def* myVar = ...
> > }
> >
> > *def* index() {
> > *var* myVar = ...
> > }
> >
> > *def* index() {
> > *Object* myVar = ...
> > }
> >
> > *Object* index() {
> > *def* myVar = ...
> > }
> >
> > *Object* index() {
> > *var* myVar = ...
> > }
> >
> > *Object* index() {
> > *Object* myVar = ...
> > }
> >
> > I would like to write controllers like this:
> >
> > *var* index() {
> > *var* myVar = ...
> > }
> >
> > to keep the code clean and coherent with the Groovy documentation that
> > states clearly that *"If you think of def and var as an alias of Object,
> > you will understand in an instant."*
> >
> > Is this enough of an argument to ask for an implementation of `var` that
> is
> > fully intrechangable with `def`?
> >
> > Please let me know what is your opinion on that,
> > cheers,
> > Gianluca
> >
> > Gianluca Sartori
> > --
> > Cell. +39 388 1026822
> >
>
>
