Look and think good things about D

[Ary Borenszweig]

On 11/15/13 7:54 AM, bearophile wrote:
> Jacob Carlborg:
>
>> What does this show, that ranges is slow in D?
>
> It shows that D is awesome. Do you know other languages that allow you
> to write two programs to solve that problem as short/simple and as fast
> as those two? :-)
>
> Bye,
> bearophile

Probably Crystal.

Here's what I was able to do in some minutes:

---
if ARGV.length != 1
   puts "missing argument: n"
   exit 1
end

n = ARGV[0].to_i
str = "1"
buffer = String::Buffer.new(20)
n.times do
   puts str.length
   str.each_chunk do |digit, count|
     buffer << '0' + count
     buffer << digit
   end
   str = buffer.to_s
   buffer.clear
end
---

With n=70 it takes about 4.89s. With n=45 it takes about 0.012s.

And with Crystal you could do the second version as well, because you 
have access to low level stuff like pointers. And also, the language is 
pretty new so there's still a lot of optimizations to be done.

I also thought ranges were pretty fast because of their nature. Why are 
they slow in this example?