T9.frink

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// Program to find ambiguous words using "T9" phone entry method.
// Users of this class will only use the encipher and decipher functions.

class T9
{
   class var initialized = false;

   // dict is a dictionary of words, keyed by their numeric values, values
   // are an array of words that this number maps to.
   class var dict = new dict

   // Dictionary of mappings from letters to numbers.
   class var phonedict = new dict
   
   class initialize[] :=
   {
      phonedict@"a" = "2"
      phonedict@"b" = "2"
      phonedict@"c" = "2"

      phonedict@"d" = "3"
      phonedict@"e" = "3"
      phonedict@"f" = "3"

      phonedict@"g" = "4"
      phonedict@"h" = "4"
      phonedict@"i" = "4"

      phonedict@"j" = "5"
      phonedict@"k" = "5"
      phonedict@"l" = "5"

      phonedict@"m" = "6"
      phonedict@"n" = "6"
      phonedict@"o" = "6"

      phonedict@"p" = "7"
      phonedict@"q" = "7"
      phonedict@"r" = "7"
      phonedict@"s" = "7"

      phonedict@"t" = "8"
      phonedict@"u" = "8"
      phonedict@"v" = "8"

      phonedict@"w" = "9"
      phonedict@"x" = "9"
      phonedict@"y" = "9"
      phonedict@"z" = "9"

      // Effectively, this is a "set" of the words we've seen.
      // TODO: need to implement efficient sets.
      usedDict = new dict

      // Paths to several Moby wordlists (not included)
     // The wordlist files are part of the Moby wordlist project, available at:
     //   http://icon.shef.ac.uk/Moby/
      files = ["file://///home/eliasen/prog/mobydict/mwords/singlewords.txt",
      "file://///home/eliasen/prog/mobydict/mwords/compoundwords.txt",
      "file://///home/eliasen/prog/mobydict/mwords/names.txt",
      "file://///home/eliasen/prog/mobydict/mwords/places.txt"]

      // Load in the wordfiles and convert words to their numeric values
      for file = files
         numeric[read[file], usedDict]  // Read in wordlists 

      initialized = true
   }
   
   //orig = read["file:///c:/prog/frink/rabbitorig.txt"]

   // Decipher a string.
   class decipher[string] :=
   {
      if (! initialized)
         initialize[];
      
      string =~ %s/(\d+)/decipherNum[$1]/gse
   }

   //println[orig]

   // Function to turn a text into its string representations
   // and insert each word mapping into a dictionary.
   // 
   class numeric[string, usedDict] :=
   {
      words = split[%r/\s+/s, string]  // Split into words
      for word = words
      {
         if word =~ %r/[^A-Za-z]/  // Discard non-alphabetic words.
            next

         if word =~ %r/[A-Z]{2,}/   // Two or more uppercase letters?  Skip 'em.
            next

         capWord = lowercase[word]  // Make all keys uppercase

         if (usedDict@capWord)      // Already seen it?
            next

         usedDict@capWord = true    // Mark word as used
         
         // Make numeric value.  This could be done more concisely if we
         // had a map[] function.

         ret = capWord
         ret =~ %s/([a-z])/phonedict@$1/ges

         //      println["$capWord -> $ret"]

         // See if number exists already
         if (dict@ret != undef)
         {
            dict@ret.push[word]  // Already exists
            //         println[dict@ret]    // Comment in to see hash collisions
         } else
         dict@ret = [word]    // Doesn't exist, create a one-element array
      }
   }


   // Function to do enciphering, for reference.  Note that it's a *whole*
   // lot easier to encipher than decipher.
   class encipher[str] :=
   {
      if !initialized
         initialize[];

      lc[str] =~ %s/([A-Za-z])/phonedict@$1/ges
   }


   // Function to decipher a single number to its probable word(s)
   // This should be treated as a private function.
   class decipherNum[num] :=
   {
      rev = dict@num

      if (! rev)
         return num       // Word not found, print numeric value
      else
         if (length[rev] == 1)
            return rev@0  // Only one word; print without brackets
         else
            return rev    // More than one mapping, print array
   }
}


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This is a program written in the programming language Frink.
For more information, view the Frink Documentation or see More Sample Frink Programs.

Alan Eliasen was born 20217 days, 15 hours, 24 minutes ago.