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From Krzysztof Kowalczyk <kowalczyk.krzysz...@gmail.com>
Subject Re: Named function arguments in Groovy
Date Wed, 23 Nov 2016 21:35:10 GMT
Hi Michael,

Have you flowing feature request?
https://issues.apache.org/jira/browse/GROOVY-7956

Check links in the comments.

Regards,
Krzysztof

On 23 November 2016 at 20:01, OC <ocs@ocs.cz> wrote:

> Michael,
>
> On 23. 11. 2016, at 8:50, Michael Rüegg <rueegg.michael@gmail.com> wrote:
>
> > The problem with this approach is that for a user of this DSL, it is not
> obvious which parameters are expected and what their names are (beside
> documenting it, but who is going to read that ;-)).
>
> Well, if someone is too sexy to read documentation, serves him right, does
> it not?
>
> That said, some way of checking argument names would be nice.
>
> > How can I achieve named function arguments with “real" syntax in Groovy?
> Is there an alternative to using maps for this?
>
> It does not need to be an alternative to map; just perhaps adding a way to
> inform the compiler which names (and types) are allowed and which are not.
>
> I believe you could DIY through ASTTs, but aside of that, far as I can
> say, there's currently no way compile-time. Runtime, of course, you can DIY
> much easier :)
>
> > By the way, I think it is kind of misleading for a beginner that the
> following compiles
>
> I would rather think it would be highly suspicious if it did not compile,
> for beginner or experienced programmer just as well.
>
> > but does not pass the arguments in the intended order:
>
> It does. The order is as declared.
>
> > foo(a="a", c=“c", b=“b") {
> >  // a == a, b == c, c==b
> > }
> >
> > Is this intended behaviour?
>
> Definitely, since it is nothing Groovy-specific: three very plain
> positional arguments, whose values happen to be given using expressions. In
> this case, assignment expressions.
>
> There are two a's (two b's, two c's) -- one outside the method (and that's
> the one you assign the value to by the expression); another inside (and it
> gets the result of the appropriate expression, positionally).
>
> Possibly you have tested that in a script, which might get confusing for
> it (sort of) creates those outside a, b and c for you automatically without
> you having to declare it. Try it in a normal class, and you'll see the
> trick.
>
> All the best,
> OC
>
>

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