The ActiveRecord example, to me, is an example of "clever". Any code that exhibits "spooky action at a distance" is too clever, in my opinion. When I can't hand trace a method or function and see what's going on, it is too "clever" - or at least it isn't "explicit".
Spring in the Java world does this with it's XML configuration and code injection based on annotations. You can't decipher what's going on by code examination. To code in Spring you have to fully understand the Spring framework. Rails (to me at least) is similar. The steep learning curve makes them less hackable.
With Clojure, by contrast, you can always look at a function or macro and (eventually) grok what's happening.
Hah. I was with you up until the last line. Macros do exactly the same thing as spring-aop - they transform your function into some different code, so that when it's called it does something different to what was written.
/scala guy, very worried by the introduction of macros, despite (perhaps even because of) all the cool things they can do
Certainly macros can be hard to decipher, however they don't set up this spooky action at a distance, for example a annotation signaling bytecode injection. There's no way to hand-trace through that; the only solution is to learn the library / framework in-depth.
Honestly I don't see the difference. If you're stepping through in a debugger, you see the "real" code. If you're just reading the code, you read something that looks like a function and then have to jump far away to the annotation or macro to find out what actually happens. Assuming IDE integration it's really no easier or harder to jump to a spring aspect than it is to a macro.
Many annotations in Spring are merely markers used during startup to wire things up or generate bytecode on the fly. There is no way to jump to the actual code.
Spring in the Java world does this with it's XML configuration and code injection based on annotations. You can't decipher what's going on by code examination. To code in Spring you have to fully understand the Spring framework. Rails (to me at least) is similar. The steep learning curve makes them less hackable.
With Clojure, by contrast, you can always look at a function or macro and (eventually) grok what's happening.