• Graham Fawcett (12/12) May 04 2010 Hi folks,
• Ellery Newcomer (13/25) May 04 2010 (format t "~A { ~A }~%" num (reverse words))
• bearophile (31/34) May 05 2010 Three years ago I have written this, for D1 with Phobos that doesn't use...

Graham Fawcett <fawcett uwindsor.ca> writes:

Hi folks,

I just read a provocative critique of a blog article comparing C++ to 
Lisp:

http://funcall.blogspot.com/2010/05/c-vs-lisp.html

I've enjoyed using Lisp languages in the past, and appreciate that D 
offers a lot of metaprogramming features that could probably result in a 
cleaner, shorter equivalent than the worked C++ example in the articles.

Not looking for any language wars here: I just thought someone might 
enjoy discussing features of D that put it ahead of C++ in this type of 
programming.

Best,
Graham

Ellery Newcomer <ellery-newcomer utulsa.edu> writes:

On 05/04/2010 03:32 PM, Graham Fawcett wrote:
 Hi folks,

 I just read a provocative critique of a blog article comparing C++ to
 Lisp:

 http://funcall.blogspot.com/2010/05/c-vs-lisp.html

 I've enjoyed using Lisp languages in the past, and appreciate that D
 offers a lot of metaprogramming features that could probably result in a
 cleaner, shorter equivalent than the worked C++ example in the articles.

 Not looking for any language wars here: I just thought someone might
 enjoy discussing features of D that put it ahead of C++ in this type of
 programming.

 Best,
 Graham

(format t "~A { ~A }~%" num (reverse words))

could be translated to

writefln("%s { %s }", num, retro(words));

except it seems like writefln doesn't actually print out the contents of 
an arbitrary range.

Personally, I much prefer d to lisp regarding hash tables, and I think 
d's ranges is a cleaner abstraction than whatever lisp has or doesn't have.

I do miss lisp's macros when programming in d, though. Sometimes 
template or string mixins do the job well enough, sometimes they don't. 
Things like reduce!("f(a) > b")(range), where f isn't defined in 
std.algorithm, or it's defined as something else (does this actually 
happen?)

bearophile <bearophileHUGS lycos.com> writes:

Graham Fawcett:
 I just read a provocative critique of a blog article comparing C++ to 
 Lisp:
 http://funcall.blogspot.com/2010/05/c-vs-lisp.html

Three years ago I have written this, for D1 with Phobos that doesn't use my
dlibs1:

import std.stdio, std.stream, std.string, std.ctype, std.gc;

void traduct(char[] n, char[] digits, int start, char[][] words,
char[][][char[]] gdict) {
    if (start >= digits.length)
        writefln(n, ": ", words.join(" "));
    else {
        auto found_word = false;
        for(auto i = start; i < digits.length; i++)
            if (digits[start .. i+1] in gdict) {
                found_word = true;
                foreach(hit; gdict[digits[start .. i+1]])
                    traduct(n, digits, i+1, words ~ [hit], gdict);
            }
        if (!found_word && (!words || (words &&
!std.ctype.isdigit(words[words.length-1][0]))))
            traduct(n, digits, start+1, words ~ [digits[start..start+1]],
gdict);
    }
}

void main() {
    std.gc.disable(); // to speed up the program a bit
    auto gtable = maketrans("ejnqrwxdsyftamcivbkulopghzEJNQRWXDSYFTAMCIVBKULOPGHZ",
                           
"0111222333445566677788899901112223334455666777888999");

    char[][][char[]] gdict;
    foreach(char[] w; new BufferedFile("dictionary.txt"))
        gdict[w.translate(gtable, "\"")] ~= w.dup;

    foreach(char[] n; new BufferedFile("input.txt"))
        traduct(n, n.removechars("/-"), 0, [], gdict);
}


I think it's good enough compared to the Lisp version. I think it's better on
the version of this program that was in the Digitalmars site.

Bye,
bearophile