During our Boston D Meetup today, we went through and
deconstructed Walter's wonderfully elegant blog post from 2012
called "Component Programming in D"
http://www.drdobbs.com/article/print?articleId=240008321&siteSectionName=architecture-and-design
I stumbled upon this gem (and another score or so articles on the
digital mars site) a few days back, while following various
hyperlinks, within and around the blog on Walter's take on what
was C's biggest mistake which has been getting a lot of comments
over the past few days.
This post which I have been trying to digest bit-by-bit over the
past few days, made me realize why I fell in love with D in the
first place. To top it all, Steven played a lightening talk from
2018, called "values as types" by Andreas
(https://youtu.be/Odj_5_pDN-U?t=21m10s) which is a parody on C++
and is so utterly ludicrous, we could not stop laughing. Anyway,
back to the point.
During the same period, but independent of the thread on C's
mistake, I found that Kotlin has something called "Extension
Functions" and "Extension Properties"
(https://kotlinlang.org/docs/reference/extensions.html) via. the
following article on Medium
https://medium.com/@magnus.chatt/why-you-should-totally-switch-to-kotlin-c7bbde9e10d5
Specifically Item #14.
What I saw/read seemed eerily familiar. Almost like a "wolf in
sheeps clothing". The example screamed of UFCS. Then, later,
while reading the above Kotlin documentation, I saw a reference
being made to similar functionality in C# and Gosu (apparently a
programming language that I have never heard of before today)
called Extensions.
Furthermore, I found that Project Lombok
(https://projectlombok.org/features/experimental/ExtensionMethod)
has tried to make this idiom/functionality available in Java
through a @ExtensionMethod annotation. This also almost exactly
represent UFCS functionality, though much more cludgy, I must say.
Therefore, after reading the word "Extension" in three different
contexts, I started wondering and various questions came to mind,
starting with---Whence came UFCS?
a. Did Walter and/or Andrei invent it independently of C#?
b. Was it called UFCS in some other language?
c. Were they not aware of Extensions when they coined UFCS?
d. Are UFCS and Extensions really one and the same thing?
e. If not, what is/are the difference(s)? And is this why a
different term/acronym was coined?
As far as I can tell a Google search on UFCS leads to only
material on D and a Wikipedia entry mentioning Stroustrup and
Sutter's proposal from 2016 to extend C++ to have this facility.
It is likely that the Wikipedia article is severely incomplete in
its historical connections as there is no mention of C# or that
of Walter's 2012 Dr. Dobbs post which already lists it towards
the end---in the list of features that D has which allows the
creation of elegant components---among other dozen or so features.
In the end I thought I might as well dump my thoughts on the D
forum and hear straight from the horse's (or horses')
mouth(s)---so to speak.
--
Sameer
