Lazy list/range comprehensions

[Jimmy Cao]

The Python version:

sum(item * item for item in sequence)

can be translated to English as:

"Sum of (item * item) foreach item in sequence"

While the D version:

reduce!("a+b")(map!("a*a")(sequence), 0);

looks to me like:

Reduce! a plus b map! a times a (sequence) (and a random 0 here).



On Sun, Oct 3, 2010 at 12:59 PM, Andrei Alexandrescu <
SeeWebsiteForEmail at erdani.org> wrote:

> On 10/03/2010 10:37 AM, bearophile wrote:
>
>> Peter Alexander:
>>
>>  Out of curiosity, what syntax did you propose?
>>>
>>
>>
>> http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=73868
>>
>>
>>
>>  That said, the current D way of writing it isn't all that different
>>> from Python:
>>>
>>> return reduce!("a+b")(map!("a*a")(sequence), 0);
>>>
>>
>> That's many times worse than the Python syntax.
>>
>
> This entails there's a way to measure that. How?
>
>
>  Array/range comprehensions are syntax sugar, their point is to give
>> something clean and readable that helps chunking:
>> http://en.wikipedia.org/wiki/Chunking_%28psychology%29
>>
>
> You'd need to bring a pointer to a document that confirms that (and how)
> array and range comprehensions have helping chunking as their point. I
> googled for
>
> array comprehensions help chunking
>
> to no avail.
>
>
> Andrei
>
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