D vs Go on reddit

[spir]

On 02/03/2011 07:16 PM, Ulrik Mikaelsson wrote:
> 2011/2/3 "Jérôme M. Berger"<jeberger at free.fr>:
>>         Then why has not Lisp won over all competition years ago?
>>
>>                 Jerome
> You mean why(not(has(won(lisp,all(competition)),years_ago))) ?
>
> Jokes aside, I think people in language-debates often forget that
> high-level languages are really just layers of syntactical sugar over
> machine-code. ASM is syntactical sugar over machince-code, C is
> syntactical sugar over ASM, and D is mostly syntactic sugar over C.
> They are merely ways to streamline certain programming-models, into a
> language that encourages those idioms and constructs. Just about
> anything that can be written in D, can be written with equivalent
> semantics in C, but the D-version is likely to be faster to write, and
> faster to comprehend.

The first part of this paragraph says, imo, something different from the second 
part.
I think there are two kinds of features over a core language: ones are as you 
say plain sugar; others (let's call them conceptual) introduce new semantic 
notions. To distingish those 2 kinds, one needs to observe how translation of 
code involving a given feature into the core language is to be done:
* sugar features only require plain rewriting
* conceptual features require a transformation of the code

The purpose of PL design, imo, is to figure out what kinds of notions people 
use to "model" and define them in the language. Then, expressing a model 
holding such notions using this language is direct. If a given notion does not 
exist in the language used, then one needs to transform the model before beeing 
able to express it; then, the code does not look like what it means (or 
should). This is what I call "semantic distortion" (and others conceptual 
mismatch).

The above distinction of 2 kinds of features is taken from a document called 
(IIRC) "Expressive power of Programming languages", which itself builds on a 
similar distinction made in the field of logic formal languages.

> The purpose of higher-level languages is to encourage "good"
> programming style and readability. Period. The syntax is crucial here,
> it determines which constructs will become readable, and which won't,
> which in turn determines the mind-set of the programmer. Which is why
> I consider syntactic sugar to be seriously under-appreciated and
> undervalued in many language decisions.

Syntax & semantics play together in "linguistic" notions built into a language. 
Sugar features are purely syntactic, library features purely 
semantic/conceptual, linguistic features are both.

Trivial example: the notion of iteration expressed by 'foreach'. Why is it so 
successful, while it's usually trivial to do without it? I guess the reason is 
foreach expresses, as is, a notion that exists in the (mental) "language of 
modelling". Without foreach, one needs to transform this notion into different 
semantics, using a general purpose looping construct (while), also involving 
elements that do not belong to the model (node pointer, ordinal index,...).
Since this is an extremely common idiom, we are used to decode it as 
"iteration" at first sight. But the code does /not/ inherently express 
iteration by itself:

     foreach (node ; list) {
         auto element = node.element;
         doSomethingWith(element);
     }

     Node* node = list;
     while (node) {
         auto element = node.element;
         doSomethingWith(element);
         node = node.next;
     }


Denis
-- 
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vita es estrany
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