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From "Winnebeck, Jason" <>
Subject RE: Macro methods proposal
Date Fri, 23 Sep 2016 13:46:27 GMT
Assuming the AST can’t already form the right signature in the JAR for IDE to see, I can
think of one solution:

public class MacroMethods {
  @Macro public static <T> T safe(T param) {
    def ctx = Macros.macroContext
    def exp = Macros.getExpression(param)
    //original code from example…

In this case, the IDE sees a method with an appropriate signature, and knows the method returns
the same type as the argument, but you still have access to the macro context via static methods
which could be implemented using thread locals or similar. The signature could also be used
to restrict the type of the expression allowed, although in most cases I’d expect Object
or a “T” to be used.


From: Sergei Egorov []
Sent: Friday, September 23, 2016 9:27 AM
Subject: Re: Macro methods proposal

Hey Jason,

Left a comment on #3.

Yes, the method signature of Macro methods is not the same as the call site. But, for the
given call site, IDE can easily determine the signature, and I'm pretty sure it has all the
information already. Plus, this is a new language feature anyway, so IDE will have to support
it, at least I see no other options for now.
See about the syntax as

Macro methods inherit all the rules of Groovy AST transformations - they work only for Groovy


On Fri, Sep 23, 2016 at 4:02 PM Winnebeck, Jason <<>>
This is a really cool idea, especially I like the idea of the compile-time checked ORM example.
I wonder whether or not the use in simple cases is productive given JIT inlining and branch
prediction when branching on a constant, and decided to phrase that question in an issue

I noticed that the method signature for the macro method does not match the signature used
at the call site – does this confuse IDEs like IntelliJ, or does this actually work properly
because ASTs must be in a separate JAR, so the @Macro AST has already run to generate a stub
with the proper call signature that the IDE sees?

Last question, is there any interaction with Java? That is, is it possible for an implementation
to provide a “normal” version of the method like in your “warn” example so that Java
can call it as a normal method while in Groovy the transform would be applied? In that way
you could make a logging library that would work like a normal logging library in Java but
in Groovy would apply the macro transformations.


From: Sergei Egorov [<>]
Sent: Friday, September 23, 2016 5:58 AM
Subject: Macro methods proposal

Hey, everyone.

It's been awhile since last time I participated in Groovy.
I was mostly in read-only mode for the last two years.

With this move, I hope to change it.

I created a proposal for macro methods (no ETA, initially aimed to 3.0) because I think they
are great for the future of Groovy and compile time metaprogramming.

You can find the proposal here:

Not sure how Apache people will react on it since it's on GitHub, but it was the simplest
way for me to share and discuss it.

Please note that macro methods are not the same as MacroGroovy - another thing from me already
merged to groovy-core. But, MacroGroovy can and should be implemented with macro methods.

Grammar and clearness are not my strong points, but we can improve the proposal altogether.

For the few years Guillaume, Baruch, Cedric and others were trying to spread the word  about
macro methods, but the problem here that they are something really new and I didn't succeed
explained them back in the days.

So, I'm inviting everyone to discuss them, by raising GitHub issues, or here, in mail list,
to make them more clear for everyone, including end users.

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