But the call to Foo#baz() coud return an e.g. GroovyVoidObject instance,
which in turn throws a "cannot return void from method" if that happens
to be the last expression in your example, no ?
It feels like returning null here is just a stopgap, not anything one
actually wants to have in the language...
I don't expect the dynamic compiler to be changed, but should we really
mirror the dynamic comiler behavior in the static compiler in this case
? I think it would be much more least surprise in the @CompileStatic case...
Cheers,
mg
PS: Calling void methods better be fine, otherwise why do they exist in
the first place ;-) - I am/was always referring to my initial question,
so the whole thread is about expecting/using void method call results
somewhere...
On 04.09.2018 01:41, Paul King wrote:
Calling void methods is fine. Expecting a result is the point in question.
For dynamic Groovy, you can't always tell which case you have:
class Foo {
def bar() { 42 }
void baz() { }
}
def method(boolean condition, delegate, meth1, meth2) {
if (condition) delegate."$meth1"()
else delegate."$meth2"()
}
println method(true, new Foo(), 'bar', 'baz') // 42
println method(false, new Foo(), 'bar', 'baz') // null
Here, "method" is expecting to return some value that happens to be
the last expression, i.e. the result of the if/then/else expression,
so we return null in such cases.
Cheers, Paul.
On Tue, Sep 4, 2018 at 7:38 AM MG <mg...@arscreat.com
<mailto:mg...@arscreat.com>> wrote:
What I meant was: What sense does letting void methods be called make
for the dynamic case, i.e. the dynamic compiler ? From a programmer's
perspective, i.e. what is a programming use case for that
feature/behavior, in dynamic Groovy ?
Of course I can do the following in dynamic Groovy:
// Groovy 2.5.0
class Goo {
//void nogoo() { return 123 } // Dynamic Groovy compiler:
RuntimeParserException: Cannot use return statement with an
expression on a method that returns void
void nogoo() { 123 }
}
final goo = new Goo()
println "original: goo.nogoo()=${goo.nogoo()}"
goo.metaClass.nogoo = { return 456 }
println "mopped: goo.nogoo()=${goo.nogoo()}"
Which will build, run, and output
original: goo.nogoo()=null
mopped: goo.nogoo()=456
i.e. returning 456 from a void method in the second case.
But if I am using a library that includes the Goo class, why would I
ever expect a return value from the nogoo method (and therefore call
it), considering its return type is void ? And if I control the Goo
class myself, why would I not just change its return type to int
or def ?
Cheers,
mg
On 03.09.2018 22:36, Jochen Theodorou wrote:
> On 03.09.2018 17:13, mg wrote:
>> But in what scenario does the dynamic behavior make sense ?
>
> for a static compiler? none other than being compatible
>
> bye Jochen
>
