On 2011-03-07 01:10, Jonathan M Davis wrote:
On Sunday 06 March 2011 10:03:05 Tomek Sowiński wrote:
bearophile bearophile napisał:
Haskell is full of function calls, so the Haskell designers have
used/invented several different ways to avoid some parenthesys in the
code.
From what I've seen if you remove some parenthesis well, in the right
places, the resulting code is less noisy, more readable, and it has less
chances to contain a bug (because syntax noise is a good place for bugs
to hide).
One of the ways used to remove some parenthesys is a standard syntax
that's optionally usable on any dyadic function (function with two
arguments):
sum a b = a + b
sum 1 5 == 1 `sum` 5
The `name` syntax is just a different way to call a regular function with
two arguments.
In Haskell there is also a way to assign an arbitrary precedence and
associativity to such infix operators, but some Haskell programmers
argue that too much syntax sugar gives troubles (
http://www.haskell.org/haskellwiki/Use_of_infix_operators ).
In D the back tick has a different meaning, and even if in D you use a
different syntax, like just a $ prefix, I don't know how much good this
syntax is for D:
int sum(int x, int y) { return x + y; }
int s = sum(1, sum(5, sum(6, sum(10, 30))));
Equals to (associativity of $ is fixed like this):
int s = 1 $sum 5 $sum 6 $sum 10 $sum 30;
So I think it's not worth adding to D.
I vaguely recall someone mentioned infixablility by naming convention.
int _add_(int x, int y);
int s = 1 _add_ 5 _add_ 10;
As a feature of its own, it's just sugar. But if introducing infix
operators were contingent on banishing classic operator overloading, then
it is worthwhile.
LOL. And _what_ benefit would banishing classic operator overloading have? A
function named add could be abused in _exactly_ the same ways that + can be.
You could implement operator overloading without any special
cases/support in the language, like Scala does. In Scala
3 + 4
Is syntax sugar for:
3.+(4)
It's possible because of the following three reasons:
* Everything is an object
* Method names can contain other characters than A-Za-z_
* The infix syntax discussed in this thread
Implementing operator overloading like this also allows you to add new
operators and not just overloading existing ones.
--
/Jacob Carlborg
