c++ vs lisp -- D perspective

bearophile bearophileHUGS at lycos.com
Wed May 5 02:19:17 PDT 2010

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",

    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.


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