PS
The ITypeConverter interface definition is here:
https://picocli.info/apidocs/picocli/CommandLine.ITypeConverter.html
On Mon, Nov 16, 2020 at 21:08 Remko Popma <remko.po...@gmail.com> wrote:
> Hi all,
>
> I have a question about passing closures to annotations in Groovy.
> To illustrate, consider the @Option annotation in the picocli library.
> Relevant attributes are `completionCandidates` and `converter`, defined in
> Java as follows:
>
> @Retention(RetentionPolicy.RUNTIME)
> @Target({ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER})
> public @interface Option {
> Class<? extends ITypeConverter<?>>[] converter() default {};
> Class<? extends Iterable<String>> completionCandidates() default
> NoCompletionCandidates.class;
> ...
> }
>
> I am working on a change to picocli
> <https://github.com/remkop/picocli/issues/1258> that would allow users to
> specify closures for these and other attributes.
> User code could look like this:
>
> @Option(names = '-s', completionCandidates = {["A", "B", "C"]})
> @Field String s
>
> @Option(names = '-a', converter = [{ str -> MessageDigest.getInstance(str)
> }] )
> @Field MessageDigest algorithm
>
> I think this would be a nice addition and would make picocli more "groovy".
>
> I have a prototype implementation, but it appears that only the first
> example ( completionCandidates = {["A", "B", "C"]} ) works as expected.
> When stepping through my prototype test in a debugger, it looks like the
> second example (the converter attribute) receives a zero-length array of
> classes when invoked from Groovy. I tried with Groovy 2.4.10 and 3.0.6.
>
> Is this a known limitation of Groovy?
> Is there a way to work around this?
>
> I can provide an example project to reproduce this if that is helpful.
>
> Kind regards,
> Remko
>
>
