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August 29, 2007
Lisp-Java-D
As an exercise, my take at this problem (D 1.X):
http://www.digitalmars.com/d/lisp-java-d.html


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

void traduct(string n, string digits, int start, string[] words, string[][string] 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() {
 auto gtable = maketrans("ejnqrwxdsyftamcivbkulopghzEJNQRWXDSYFTAMCIVBKULOPGHZ",
                         "0111222333445566677788899901112223334455666777888999");

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

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


It's faster than my Python version and it shows that D code can be positively coincise too.
(I have found ways to speed this D code up, using a bit lower-level coding, disabling the GC in the beginning, etc, but I think this is a good speed/linecount compromise, and it looks readable enough.)

Bye,
bearophile
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