On Thursday, 31 August 2017 at 14:52:43 UTC, jmh530 wrote:
On Wednesday, 30 August 2017 at 15:59:32 UTC, Jean-Louis Leroy
What happens here is that kick(Animal) is shadowed by
kick(Dog). kick(Animal) is a method but it appears to the user
and the compiler as an ordinary function - which is generally
good. As such it is eligible for UFCS. I would not recommend
this sort of coding, but it's everyone's choice, methods or
Likewise, methods can be overloaded (like here
A current limitation is that default arguments are not
supported (yet), although I think it's just a matter of
putting the effort in.
UFCS interacts nicely with methods because you can say
a.plus(b) even if 'plus' is an open method.
I had a chance to try out what I had suggested above and it
behaves exactly as I would have expected (i.e. it prints the
line "lassie.kick(): ctbark").
You seemed to emphasize UFCS in your response, but that really
wasn't what I was intending to focus on. I just as easily could
have re-written Dog as below and compiled the program and it
would have printed the same thing. Similarly, any Dog or
Pitbull type that call kick would return "ctbark", just Animals
would return the original results.
class Dog : Animal
final string kick()
My point is one can easily mix your openmethods's dynamic
dispatch and D's static dispatch. That seems like a great thing
that you could emphasize. Simply stated: if you use
openmethods, you're not forced to only use openmethods. If you
know the type at compile-time, then you can use it. It's only
if you want to dynamically dispatch it that you would need
Indeed I misunderstood.
Well, I am very pleased that my stuff interacts well with the
rest of the language - I strive for that. However, I found that
it is difficult to get people to open their mind to the idea of
open methods, initially. Unless they come from Lisp, polymorphism
and membership are almost indissociable for them. I often have to
jump three hurdles.
1/ They're multi-methods, and I never actually had a use for
that. That is why I insist so much on openness in the article,
and throw multiple dispatch in as a bonus only half way through.
That's also why I call them "open methods" and not
"multi-methods" or "open multi-methods".
2/ It's just function overloading. Hmmm, polymorphism? But once I
get past that, it's actually a good thing. People know (more or
less) how overload resolution (or partial template specialization
for the more expert) works. So I don't need to explain the rules
governing dispatch and ambiguities in an abstract way. Usually I
just say "you already know which override will be picked - it's
the same as with compile-time overload resolution".
3/ This one is specific to D - UFCS gives me the same thing.
Hmmm, polymorphism again? But you see why I am very careful with
anything that may obscure or confuse the message.
I find the interaction of open methods and UFCS particularly cool
when implementing the "call chain" idiom (e.g.