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https://issues.apache.org/jira/browse/GROOVY-7956?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15962897#comment-15962897
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Daniil Ovchinnikov commented on GROOVY-7956:
--------------------------------------------
Another option:
{code}
def foo(a, @Named b, c, @Named d) {
println "$a $b $c $d" // note referring to named parameters as a regular ones
}
{code}
This may be compiled to a regular method with a Map as a first parameter:
{code}
def foo(Map _it, a, c) {
println "$a $_it.b $c $_it.d"
}
{code}
The parameters then may have types and/or default values:
{code}
def foo(int a, @Named String b = "hello there", c, @Named d) {
println "$a $b $c $d"
}
//compiled
def foo(Map _it, int a, c) {
_it.putAll(b: "hello there) // default parameters injected here
println "$a ${(String)_it.b} $c $_it.d" // cast to string
}
{code}
There is still need to store some metadata in the compiled code, for which this
annotation will work GROOVY-7632.
This may be implemented as an AST transformation or as a special language
feature.
Since each transformation slows the IDE, I'd go with new modifier, e.g.
{{named}}.
{code}
def foo(int a, named String b = "hello there", c, named d) {
println "$a $b $c $d"
}
{code}
This for sure will break someone's sources, but it's a step for cleaner
language.
> Allow @DelegatesTo on named arguments
> -------------------------------------
>
> Key: GROOVY-7956
> URL: https://issues.apache.org/jira/browse/GROOVY-7956
> Project: Groovy
> Issue Type: New Feature
> Components: GEP
> Reporter: Graeme Rocher
>
> In order to aid static compilation for builders we have {{@DelegatesTo}}
> which allows statically compiled code to know what the delegate of a closure
> is.
> This proposal is to allow {{@DelegatesTo}} on {{Map}} types such that IDEs
> and the static compiler can resolve the target type the named arguments are
> to be used on.
> For example:
> {code}
> class Farm {
> void animal(@DelegatesTo(Animal) Map arguments,
> @DelegatesTo(AnimalBuilder) Closure callable) {
> def animal = new Animal(arguments)
> // handle closure
> }
> }
> class Animal { String name }
> {code}
> The following code would then fail to compile :
> {code}
> def farm = new Farm()
> // compilation failure, no name property on Animal
> farm.animal(nam: "Dog") {
> }
> {code}
> It would then be down to IDEs to also provide support for code completion etc.
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