[jira] [Commented] (GROOVY-7956) Allow @DelegatesTo on named arguments

["Jason Winnebeck (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/GROOVY-7956?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15546427#comment-15546427 ] 

Jason Winnebeck commented on GROOVY-7956:
-----------------------------------------

This is an awesome idea, although I'm not sure that reusing {{@DelegatesTo}} is the most clear option... But whatever the annotation would be called, this would also be a great improvement for any "options-like" API more common in the JavaScript/TypeScript world but we see it for example with Groovy http-builder:

{code}
x.post(
        path: 'update.json',
        body: [ status: msg, source: 'httpbuilder' ],
        requestContentType: URLENC )
{code}

In this case it would be nice if the path, body, and requestContentType were known to the Groovy static compiler and IDEs. If there was a way to describe the structure (supporting even nested objects), it would be nice. There would be some question whether or not there should be a "prototype" type (as in the original proposal, like {{@Properties(Animal)}}) supported in addition to a "descriptive" form purely in annotations that would be supported even for dynamic mode (for example {{@Properties(\[x: Integer, y: Integer])}} for a method taking a Map of x,y values).

> 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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