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.
Jason
From: Sergei Egorov [mailto:[email protected]]
Sent: Friday, September 23, 2016 9:27 AM
To: [email protected]; [email protected]
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 https://github.com/bsideup/groovy-macro-methods-proposal/issues/1 about the
syntax as well
Macro methods inherit all the rules of Groovy AST transformations - they work
only for Groovy code.
BR,
Sergei
On Fri, Sep 23, 2016 at 4:02 PM Winnebeck, Jason
<[email protected]<mailto:[email protected]>> wrote:
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
https://github.com/bsideup/groovy-macro-methods-proposal/issues/3.
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.
Jason
From: Sergei Egorov [mailto:[email protected]<mailto:[email protected]>]
Sent: Friday, September 23, 2016 5:58 AM
To: [email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>
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:
https://github.com/bsideup/groovy-macro-methods-proposal
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.
Cheers,
Sergei
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