--- loncom/interface/spreadsheet/Spreadsheet.pm	2003/09/12 18:59:48	1.25
+++ loncom/interface/spreadsheet/Spreadsheet.pm	2003/09/15 20:31:01	1.26
@@ -1,5 +1,5 @@
 #
-# $Id: Spreadsheet.pm,v 1.25 2003/09/12 18:59:48 matthew Exp $
+# $Id: Spreadsheet.pm,v 1.26 2003/09/15 20:31:01 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -380,7 +380,7 @@ returns the number of items in the range
 #-------------------------------------------------------
 sub NUM {
     my $mask=&mask(@_);
-    my $num= $#{@{grep(/$mask/,keys(%sheet_values))}}+1;
+    my $num= $#{@{grep(eval("/$mask/"),keys(%sheet_values))}}+1;
     return $num;   
 }
 
@@ -397,7 +397,7 @@ sub BIN {
     my ($low,$high,$lower,$upper)=@_;
     my $mask=&mask($lower,$upper);
     my $num=0;
-    foreach (grep /$mask/,keys(%sheet_values)) {
+    foreach (grep eval("/$mask/"),keys(%sheet_values)) {
         if (($sheet_values{$_}>=$low) && ($sheet_values{$_}<=$high)) {
             $num++;
         }
@@ -419,7 +419,7 @@ returns the sum of items in the range.
 sub SUM {
     my $mask=&mask(@_);
     my $sum=0;
-    foreach (grep /$mask/,keys(%sheet_values)) {
+    foreach (grep eval("/$mask/"),keys(%sheet_values)) {
         $sum+=$sheet_values{$_};
     }
     return $sum;   
@@ -440,7 +440,7 @@ sub MEAN {
     my $mask=&mask(@_);
     my $sum=0; 
     my $num=0;
-    foreach (grep /$mask/,keys(%sheet_values)) {
+    foreach (grep eval("/$mask/"),keys(%sheet_values)) {
         $sum+=$sheet_values{$_};
         $num++;
     }
@@ -465,14 +465,14 @@ compute the standard deviation of the it
 sub STDDEV {
     my $mask=&mask(@_);
     my $sum=0; my $num=0;
-    foreach (grep /$mask/,keys(%sheet_values)) {
+    foreach (grep eval("/$mask/"),keys(%sheet_values)) {
         $sum+=$sheet_values{$_};
         $num++;
     }
     unless ($num>1) { return undef; }
     my $mean=$sum/$num;
     $sum=0;
-    foreach (grep /$mask/,keys(%sheet_values)) {
+    foreach (grep eval("/$mask/"),keys(%sheet_values)) {
         $sum+=($sheet_values{$_}-$mean)**2;
     }
     return sqrt($sum/($num-1));    
@@ -492,7 +492,7 @@ compute the product of the items in the
 sub PROD {
     my $mask=&mask(@_);
     my $prod=1;
-    foreach (grep /$mask/,keys(%sheet_values)) {
+    foreach (grep eval("/$mask/"),keys(%sheet_values)) {
         $prod*=$sheet_values{$_};
     }
     return $prod;   
@@ -512,7 +512,7 @@ compute the maximum of the items in the
 sub MAX {
     my $mask=&mask(@_);
     my $max='-';
-    foreach (grep /$mask/,keys(%sheet_values)) {
+    foreach (grep eval("/$mask/"),keys(%sheet_values)) {
         unless ($max) { $max=$sheet_values{$_}; }
         if (($sheet_values{$_}>$max) || ($max eq '-')) { 
             $max=$sheet_values{$_}; 
@@ -535,7 +535,7 @@ compute the minimum of the items in the
 sub MIN {
     my $mask=&mask(@_);
     my $min='-';
-    foreach (grep /$mask/,keys(%sheet_values)) {
+    foreach (grep eval("/$mask/"),keys(%sheet_values)) {
         unless ($max) { $max=$sheet_values{$_}; }
         if (($sheet_values{$_}<$min) || ($min eq '-')) { 
             $min=$sheet_values{$_}; 
@@ -560,7 +560,7 @@ sub SUMMAX {
     my ($num,$lower,$upper)=@_;
     my $mask=&mask($lower,$upper);
     my @inside=();
-    foreach (grep /$mask/,keys(%sheet_values)) {
+    foreach (grep eval("/$mask/"),keys(%sheet_values)) {
 	push (@inside,$sheet_values{$_});
     }
     @inside=sort(@inside);
@@ -587,7 +587,7 @@ sub SUMMIN {
     my ($num,$lower,$upper)=@_;
     my $mask=&mask($lower,$upper);
     my @inside=();
-    foreach (grep /$mask/,keys(%sheet_values)) {
+    foreach (grep eval("/$mask/"),keys(%sheet_values)) {
 	$inside[$#inside+1]=$sheet_values{$_};
     }
     @inside=sort(@inside);
@@ -713,6 +713,17 @@ ENDDEFS
 
 ######################################################
 
+=pod
+
+=item  &mask($lower,$upper)
+
+Inputs: $lower and $upper, cell names ("X12" or "a150") or globs ("X*").
+
+Returns:  Regular expression matching spreadsheet cells that are within
+the rectangle defined by $lower and $upper.  Due to the nature of the
+regular expression this result must be used inside an eval().
+
+=cut
 
 ######################################################
 {
@@ -727,78 +738,57 @@ sub mask {
     }
     $upper = $lower if (! defined($upper));
     #
-    my ($la,$ld) = ($lower=~/([A-Za-z]|\*)(\d+|\*)/);
-    my ($ua,$ud) = ($upper=~/([A-Za-z]|\*)(\d+|\*)/);
+    my ($la,$ld) = ($lower=~/([A-z]|\*)(\d+|\*)/);
+    my ($ua,$ud) = ($upper=~/([A-z]|\*)(\d+|\*)/);
     #
     my $alpha='';
     my $num='';
     #
+    # Do not put parenthases around $alpha.
+    # $num depends on the value in $1.
     if (($la eq '*') || ($ua eq '*')) {
-        $alpha='[A-Za-z]';
+        $alpha='[A-z]';
     } else {
-       if (($la=~/[A-Z]/) && ($ua=~/[A-Z]/) ||
-           ($la=~/[a-z]/) && ($ua=~/[a-z]/)) {
-          $alpha='['.$la.'-'.$ua.']';
-       } else {
-          $alpha='['.$la.'-Za-'.$ua.']';
-       }
-    }   
-    if (($ld eq '*') || ($ud eq '*')) {
-	$num='\d+';
+        $alpha=qq/[$la-$ua]/;
+    }
+    if ($ld ne '*' && $ud ne '*') {
+        # Make sure $ld <= $ud
+        if ($ld > $ud) {
+            my $tmp = $ud;
+            $ud = $ld;
+            $ld = $tmp;
+        }
+        # Here we make a regular expression using some advanced regexp
+        # abilities.
+        # (\d+) will match the digits of the cell name and dump them in
+        #     to $1
+        # (?(?{ ... code ...} pattern_if_true | pattern_if_false)) will
+        #     choose pattern_if_true if { ... code ... } is true and
+        #     pattern_if_false if { ... code ... } is false.
+        # In this case, pattern_if_true is empty.  pattern_if_false is 
+        #     'donotmatch' and will not match our cells because none of 
+        #     them end with donotmatch.  
+        # Unfortunately, the use of this type of regular expression 
+        #     requires that each match be wrapped in an eval().  Search for
+        #     $mask in this module for examples
+        $num = '(\d+)(?(?{$1>= '.$ld.' && $1<='.$ud.'})|donotmatch)';
     } else {
-        if (length($ld)!=length($ud)) {
-           $num.='(';
-	   foreach ($ld=~m/\d/g) {
-              $num.='['.$_.'-9]';
-	   }
-           if (length($ud)-length($ld)>1) {
-              $num.='|\d{'.(length($ld)+1).','.(length($ud)-1).'}';
-	   }
-           $num.='|';
-           foreach ($ud=~m/\d/g) {
-               $num.='[0-'.$_.']';
-           }
-           $num.=')';
-       } else {
-           my @lda=($ld=~m/\d/g);
-           my @uda=($ud=~m/\d/g);
-           my $i; 
-           my $j=0; 
-           my $notdone=1;
-           for ($i=0;($i<=$#lda)&&($notdone);$i++) {
-               if ($lda[$i]==$uda[$i]) {
-		   $num.=$lda[$i];
-                   $j=$i;
-               } else {
-                   $notdone=0;
-               }
-           }
-           if ($j<$#lda-1) {
-	       $num.='('.$lda[$j+1];
-               for ($i=$j+2;$i<=$#lda;$i++) {
-                   $num.='['.$lda[$i].'-9]';
-               }
-               if ($uda[$j+1]-$lda[$j+1]>1) {
-		   $num.='|['.($lda[$j+1]+1).'-'.($uda[$j+1]-1).']\d{'.
-                   ($#lda-$j-1).'}';
-               }
-	       $num.='|'.$uda[$j+1];
-               for ($i=$j+2;$i<=$#uda;$i++) {
-                   $num.='[0-'.$uda[$i].']';
-               }
-               $num.=')';
-           } else {
-               if ($lda[-1]!=$uda[-1]) {
-                  $num.='['.$lda[-1].'-'.$uda[-1].']';
-	       }
-           }
-       }
+        $num = '(\d+)';
     }
-    my $expression ='^'.$alpha.$num."\$";
+    my $expression = '^'.$alpha.$num.'$';
     $memoizer{$key} = $expression;
     return $expression;
 }
 
+#
+# Debugging routine
+sub dump_memoized_values {
+    while (my ($key,$value) = each(%memoizer)) {
+        &Apache::lonnet::logthis('memoizer: '.$key.' = '.$value);
+    }
+    return;
+}
+
 }
 
 ##