On 2012-09-05 20:22, Nick Sabalausky wrote:
As far as monkey patching, I find *not* having that to be a major
feature. :)
It has saved my ass several times. Especially recently when we started
to update Ruby 1.8 to 1.9.
While a lot of runtime reflection *can* be built in D (even if it
isn't all there right now), I am kind of annoyed at some of the
limitations. Like how it's impossible (at either compile-time or
runtime) to find the subclasses of a class. Uhh, actually that's the
only limitation I know of. There might be more though.
Hmm, I actually haven't needed that in D yet. But it's so cool in Ruby,
you can sort of hook up an event and be notified when a subclass
inherits from its base class. The subclass then gets passed to the event
handler and you can add new methods on the subclass.
* Have executing code in all level of scopes
Not sure what sure mean by this?
The obvious one is you can have executable code at the global level. The
less obvious one is you can have executable code when declaring a class:
def bar
end
class Foo
bar() # call bar
end
This is heavily used in Ruby on Rails' ActiveRecord implementation:
class Post
has_many :comments
end
class Comment
belongs_to :post
end
The cool thing is that these are just plain method class (class
methods). They will add some methods to context where they are called.
Any other language would probably need annotations or some other kind of
extra language feature to get this nice looking syntax.
Currently in D you would probably use template mixins:
class Post
{
mixin hasMany!("comments);
}
class Comment
{
mixin belongsTo!("post");
}
But I think this use case would be perfect for AST-macros or user
defined attributes/annotations:
class Post
{
@hasMany("comments");
}
class Comment
{
@belongsTo!("post");
}
Needs polish, but:
https://bitbucket.org/Abscissa/semitwistdtools/src/977820d5dcb0/src/semitwist/util/process.d#cl-49
Usage:
string str;
str = q{ return 42; };
assert( eval!int(str) == 42 );
str = q{ return "Test string".dup; };
assert( eval!(char[])(str) == "Test string" );
:)
Granted, there'd probably be a lot less overhead doing that in Ruby or
JS. But it works, more or less.
I'll have to take a look at that sometime. Is it that code that calls
RDMD to compile and run it?
--
/Jacob Carlborg
