On Friday, 28 December 2012 at 13:03:11 UTC, Russel Winder wrote:
On Fri, 2012-12-28 at 10:53 +0100, deadalnix wrote:
[…]
It depends what you mean by functional. It seems to me that
you'll find 2 major things that are usually understood as
functionnal :
- abstraction based on first class function. javascript is
the perfect example here, and is functional.
- purity and immutability.
In the most recent "Open Source Journal", Uncle Bob has stated
that all
you need to say is "no assignment" and you end up having to
invent
functional programming.
That is true. But is also quite reductive. If functional
programming can solve that problem, it is also very suited for
many other things, for instance event programming (where concept
like immutability and purity are not that useful).
If you have no tools to enforce immutability, you need to
completely break abstraction to get the benefit. This is bug
prone and will not scale (without abstraction nothing big is
achievable).
I am not sure what you mean by "break abstraction" here. Nor
how you get
to "will not scale". Can you elaborate? Thanks.
Sure. To make that clear I have to reintroduce the context : I
was answering to a post that stated that even if the language
don't support immutability, you can have immutability simply by
not mutate data.
To benefit from immutability, you have to be 100% sure that no
piece of code will mutate the data ever. If you have no support
for that, you break abstraction, because you have to know the
internal of every piece of code you use, in order to know if the
data are modified or not. If you have to know the internal of
each piece of code you use, then abstraction is broken.
If abstraction is broken, then the ability to code will be
reduced as the codebase grow, to a point where nothing is
maintainable anymore. When I say that it will not not scale, I'm
talking about scaling the technique to a bigger codebase, not
actually scaling the resulting program to bigger workload.
The subject is quite big, and I have proposed a talk about it in
DConf 2013 (I'm waiting for Walter to accept or reject).
