#!/usr/bin/perl -w
my $MAX_STRING_LENGTH = 20;#what is the max number of words you want t
+o return
my $MIN_STRING_LENGTH = 3;#what is the min number of words you want to
+ return
#seems to look "best" (still not terriffic) when the max is 20 and the
+ min is 3

#yee ol global hash
my %dataHash;


###########################
#pass in file name and then put its text in a string - stripping out a
+ll of the newlines
#looks at 'words' of size 4 at a time
###########################
sub createQuadHash{    
    my $fileName = shift(@_);
    my $allText = "";
    
    open(PHRASES, $fileName) or die "Can't open that file: $!\n";
        while(<PHRASES>){
            $allText .= $_;
        }
    close(PHRASES);
    
    $allText =~ tr/\n/ /d;#replace the newlines with spaces (just chom
+ping sometimes results in words mashed together)
    $allText =~ tr/[]()\"//d;#strip out chars that we don't want (beyo
+nd just newlines)
    #now take $allText and split it into an array
    @allTextArr = split('', $allText);
    #iterate the array and fill a hash, looking at the $_ and the one 
+to the right
    for(my $x = 0; $x < $#allTextArr; $x++){
        #make sure that the $pos2 isn't gonna be out of the array     
+   
        if($x+7 <= $#allTextArr){
            $pos1 = $allTextArr[$x].$allTextArr[$x+1].$allTextArr[$x+2
+].$allTextArr[$x+3];
            $pos2 = $allTextArr[$x+4].$allTextArr[$x+5].$allTextArr[$x
++6].$allTextArr[$x+7];
            $dataHash{$pos1}{$pos2}++;
        }
    }    
    return;
}
###########################



###########################
#from Perl Cookbook 2.10
#take in a hash - convert the values to percentages, and then return t
+hat hash
###########################
sub weight_to_dist {
    my %weights = @_;
    my %dist    = ();
    my $total   = 0;
    my ($key, $weight);
    local $_;

    foreach (values %weights) {
        $total += $_;
    }
    while ( ($key, $weight) = each %weights ) {
        $dist{$key} = $weight/$total;
    }

    return %dist;
}
###########################


###########################
#from Perl Cookbook 2.10
#take in a hash and via a weighted random, pick one of the keys based 
+on the value and return it
###########################
sub weighted_rand {
    my %dist = @_;
    my ($key, $weight);
    my $rand;

    while (1) {                     # to avoid floating point inaccura
+cies
        $rand = rand;
        while ( ($key, $weight) = each %dist ) {
            return $key if ($rand -= $weight) < 0;
        }
    }
}
###########################


###########################
#randomly pick and return a starting letter
###########################
sub startLetter{
    my $alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
    my $startLetter = substr($alphabet, int(rand(26)), 1);
    return $startLetter;
}
###########################


###########################
#randomly pick a key from the songsHash
###########################
sub randomKeyFromFirstHash{
   return ((keys %dataHash)[int rand keys %dataHash]);
}
###########################

###########################
#this returns the phrase to show to the screen/user
###########################
sub grabMarkovPhrase {
    createQuadHash('radiohead.txt');
    my $s = "";
    my $start = "";
    my $wordCount = 0;
    my %tempHash;
    my @tempArr;
    my $retStr = "";

    #randomly pick a phrase length - between 1 and the MAX_STRING_LENG
+TH
    my $stoppinTime = int((rand($MAX_STRING_LENGTH-$MIN_STRING_LENGTH)
+ + $MIN_STRING_LENGTH));

    #randomly pick a spot in the hash, then check to see if the first 
+letter is a cap letter
    #if it is, then carry on, if not, pick again
    my $fail = 0;
    while($fail != 1){
        $start = randomKeyFromFirstHash();#will be three chars
        #if the first position is a capital letter, then cool, (ord wi
+ll only look at the first)
        if(ord($start) > 64 && ord($start) < 91){
            $fail = 1;  
        }
    }
    #take the start letter and get rolling...
    $s = $start;
    $retStr .= $s;
    #count the letters followed by spaces
    while($wordCount < $stoppinTime){
        %tempHash = weight_to_dist(%{$dataHash{$s}});
        $s = weighted_rand(%tempHash);        
        $retStr .= $s;
        #count the number of words, split on the space
        @tempArr = split(' ',$retStr);
        $wordCount = scalar(@tempArr);
    }
    return $retStr;
}
###########################

print grabMarkovPhrase();
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