--- loncom/lonmaxima	2006/03/09 21:38:26	1.17
+++ loncom/lonmaxima	2007/05/15 17:28:32	1.28
@@ -3,7 +3,7 @@
 # The LearningOnline Network with CAPA
 # Connect to MAXIMA CAS
 #
-# $Id: lonmaxima,v 1.17 2006/03/09 21:38:26 www Exp $
+# $Id: lonmaxima,v 1.28 2007/05/15 17:28:32 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -31,7 +31,6 @@
 #
 
 use Expect; 
-use IPC::Open3;
 use IO::Select;
 use IO::Socket;
 use IO::File;
@@ -52,6 +51,7 @@ my $pidfile;                           #
 my $port;                              # path to UNIX socket file
 my %perlvar;                           # configuration file info
 my $lastlog;                           # last string that was logged
+
 use vars qw($PREFORK $MAX_CLIENTS_PER_CHILD %children $children $status
 	    $pidfile $port %perlvar $lastlog);
  
@@ -247,27 +247,32 @@ sub make_new_child {
 
         my $command=Expect->spawn('maxima');
         $command->log_stdout(0);
-
+	#$command->log_file("$execdir/logs/lonmaxima.session.log");
         &getmaximaoutput($command);
 
         for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
-           &status('Accepting connections');
-           my $client = $server->accept()     or last;
-           print $command "kill(all);reset();\n";
-           &getmaximaoutput($command);
-           while (my $cmd=<$client>) {
-              &status('Processing command');
-              print $command &unescape($cmd);
-              my $reply=&getmaximaoutput($command);
-              print $client &escape($reply)."\n";
-              if ($reply=~/^Error\:/) {
-                 &logthis('Died through '.$reply);
-                 $client->close();
-                 $command->hard_close();     
-                 exit;
-              }
-              &status('Waiting for commands');
-           }
+            &status('Accepting connections');
+            my $client = $server->accept()     or last;
+            print $command ("reset;display2d:false;kill(all);\n");
+	    &getmaximaoutput($command,2);
+            &sync($command);
+            my $syntaxerr = 0;
+            while (my $cmd=<$client>) {
+                &status('Processing command');
+                print $command &unescape($cmd);
+                my ($reply,$syntaxerr) = &getmaximaoutput($command,1);
+                print $client &escape($reply)."\n";
+                if ($syntaxerr) {
+                    last;
+                } elsif ($reply=~/^Error\:/) {
+                    &logthis('Died through '.$reply);
+                    $client->close();
+                    $command->hard_close();     
+                    exit;
+                }
+	        &sync($command);
+                &status('Waiting for commands');
+            }
         }
 
         # tidy up gracefully and finish
@@ -281,23 +286,68 @@ sub make_new_child {
     }
 }
 
+{
+    my $counter;
+    sub sync {
+	my ($command)=@_;
+	$counter++;
+	my $expect=$counter.time;
+	print $command "$expect;\n";
+	while (1) {
+	    my $output=&getmaximaoutput($command,1);
+	    if (($output=~/\Q$expect\E/) || ($output=~/^Error\:/)) {
+		return;
+	    }
+	}
+    }
+}
+
 sub getmaximaoutput {
-    my ($command)=@_;
-    my (undef,$error,undef,$output)=$command->expect(20, -re => '\(\%i\d+\)');
+    my ($command,$numcheck)=@_;
+    my $regexp = '\(\%i\d+\)';
+    my $syntaxerr=0;
+    if ($numcheck) {
+       	if ($numcheck eq 2) {
+	    # command was the killall so should get a full reset on
+	    # command numbers
+	    $regexp = '(\(\%i(1)\)|Incorrect syntax\:)';
+	} elsif ($command->match() =~ /\(\%i(\d+)\)/) {
+            my $nextmatch = $1+1;
+            $regexp = '(\(\%i'.$nextmatch.'\)|Incorrect syntax\:)';
+        }
+    }
+    my $timeout = 20;
+    my (undef,$error,$matched,$output) =
+	$command->expect($timeout, -re => $regexp);
+
+    if ($numcheck && $matched eq 'Incorrect syntax:') {
+	$syntaxerr = 1;
+	if (wantarray) {
+	    return ($matched,$syntaxerr);
+	} else {
+	    return $matched;
+	}
+    }
     if ($error) {
-       return 'Error: '.$error;
+	return 'Error: '.$error;
     }
+    $output =~ s/\r+//g; # Remove Windows-style linebreaks
     my $foundoutput=0;
     my $realoutput='';
     foreach my $line (split(/\n/,$output)) {
        if ($line=~/\;/) { $foundoutput=1; next; }
        if (!$foundoutput) { next; }
-       my ($label)=($line=~s/^(\(\%o\d+\))//);
+       if ($line=~/^Incorrect syntax:/) { $syntaxerr = 1; next; }
+       (my $label, $line) = ($line=~ /^(\(\%o\d+\))(.+)$/);
        if ($label) {
-          $label=~s/\S/ /g;
-          $line=$label.$line;
+           $label=~s/\S/ /g;
+           $line=$label.$line;
        }
        $realoutput.=$line."\n";
     }
-    return $realoutput;
+    if (wantarray) {
+        return ($realoutput,$syntaxerr);
+    } else {
+        return $realoutput;
+    }
 }