On Wednesday, 23 January 2013 at 07:57:10 UTC, Andrei
Alexandrescu wrote:
Martin Odersky confessed to me being quite worried about the
possible community reaction to the introduction of AST macros.
I haven't kept close tabs to see how it's turning out.
Can he or you explain why ?
I completely disagree. (Sorry to foul you twice.) All AST macro
systems I've studied are considerably difficult to understand
and use effectively. By comparison, string macros are brutal
and unstructured but the kind of thing all programmer worth
their salt can get done.
2 things here.
First, that is why people used to say about templates. D shows
that this isn't a fatality.
Secondly, this is true that AST macro is probably harder to
understand. In fact, it is not expected that most programmer use
it (or at least not before I'm retired as a dev). I don't even
think any experienced dev should use it on a daily basis.
However, it opens so much doors. First, no need for a custom
compiler to test new features. Anyone can download source code
and start using some new features. We can actually integrate
field tested stuff in the language. Every D compiler can get the
new feature as well.
If a feature is controversial, I can include in in my project,
but not in D in general.
An example of such new feature is the iteration mechanism
proposed here.
However, I do think that attribute was a key piece for such
mechanism, and has been handled the most backward possible way.
So clean AST macro may have been impaired here.
Anyway, I do strongly feel like we should stop adding more stuff
now. Too much stuff is here already, some already start to
misbehave together. It is probably time to consolidate the
language, and keep that kind of stuff for a later version.
After all, many language live without most of the feature D have.
