=== modified file 'src/tools/DBD.pm'
--- src/tools/DBD.pm	2012-03-13 23:00:46 +0000
+++ src/tools/DBD.pm	2012-08-22 19:27:24 +0000
@@ -29,17 +29,18 @@
 
 sub add {
     my ($this, $obj) = @_;
-    my $obj_class;
-    foreach (keys %{$this}) {
-        next unless m/^DBD::/;
-        $obj_class = $_ and last if $obj->isa($_);
-    }
-    confess "Unknown object type"
-        unless defined $obj_class;
+    my $obj_class = ref $obj;
+    confess "DBD::add: Unknown DBD object type '$obj_class'"
+        unless $obj_class =~ m/^DBD::/
+        and exists $this->{$obj_class};
     my $obj_name = $obj->name;
-    dieContext("Duplicate name '$obj_name'")
-        if exists $this->{$obj_class}->{$obj_name};
-    $this->{$obj_class}->{$obj_name} = $obj;
+    if (exists $this->{$obj_class}->{$obj_name}) {
+        return if $obj->equals($this->{$obj_class}->{$obj_name});
+        dieContext("A different $obj->{WHAT} named '$obj_name' already exists");
+    }
+    else {
+        $this->{$obj_class}->{$obj_name} = $obj;
+    }
 }
 
 sub breaktables {

=== modified file 'src/tools/DBD/Base.pm'
--- src/tools/DBD/Base.pm	2012-06-27 16:58:23 +0000
+++ src/tools/DBD/Base.pm	2012-08-21 22:32:05 +0000
@@ -114,7 +114,8 @@
 
 sub init {
     my ($this, $name, $what) = @_;
-    $this->{NAME} = identifier($name, $what);
+    $this->{NAME} = identifier($name, "$what name");
+    $this->{WHAT} = $what;
     return $this;
 }
 
@@ -122,4 +123,14 @@
     return shift->{NAME};
 }
 
+sub what {
+    return shift->{WHAT};
+}
+
+sub equals {
+    my ($a, $b) = @_;
+    return $a->{NAME} eq $b->{NAME}
+        && $a->{WHAT} eq $b->{WHAT};
+}
+
 1;

=== modified file 'src/tools/DBD/Breaktable.pm'
--- src/tools/DBD/Breaktable.pm	2010-04-08 20:55:49 +0000
+++ src/tools/DBD/Breaktable.pm	2012-08-21 22:33:22 +0000
@@ -6,7 +6,7 @@
 
 sub init {
 	my ($this, $name) = @_;
-	$this->SUPER::init($name, "breakpoint table name");
+        $this->SUPER::init($name, "breakpoint table");
         $this->{POINT_LIST} = [];
         return $this;
 }
@@ -29,4 +29,11 @@
     return $this->{POINT_LIST}[$idx];
 }
 
+sub equals {
+    my ($a, $b) = @_;
+    return $a->SUPER::equals($b)
+        && join(',', map "$_->[0]:$_->[1]", @{$a->{POINT_LIST}})
+        eq join(',', map "$_->[0]:$_->[1]", @{$b->{POINT_LIST}});
+}
+
 1;

=== modified file 'src/tools/DBD/Device.pm'
--- src/tools/DBD/Device.pm	2010-04-08 20:55:49 +0000
+++ src/tools/DBD/Device.pm	2012-08-21 17:20:17 +0000
@@ -21,7 +21,7 @@
         unquote $choice;
 	dieContext("Unknown link type '$link_type', valid types are:",
 		sort keys %link_types) unless exists $link_types{$link_type};
-	$this->SUPER::init($dset, "DSET name");
+	$this->SUPER::init($dset, "device support (dset)");
 	$this->{LINK_TYPE} = $link_type;
 	$this->{CHOICE} = $choice;
 	return $this;
@@ -40,6 +40,13 @@
         my $rx = $link_types{$this->{LINK_TYPE}};
         unquote $addr;
         return $addr =~ m/^ $rx $/x;
+}
+
+sub equals {
+    my ($a, $b) = @_;
+    return $a->SUPER::equals($b)
+        && $a->{LINK_TYPE} eq $b->{LINK_TYPE}
+        && $a->{CHOICE}    eq $b->{CHOICE};
 }
 
 1;

=== modified file 'src/tools/DBD/Driver.pm'
--- src/tools/DBD/Driver.pm	2010-04-08 20:52:36 +0000
+++ src/tools/DBD/Driver.pm	2012-08-21 19:21:16 +0000
@@ -3,7 +3,7 @@
 @ISA = qw(DBD::Base);
 
 sub init {
-    return shift->SUPER::init(shift, "driver entry table name");
+    return shift->SUPER::init(shift, "driver support (drvet)");
 }
 
 1;

=== modified file 'src/tools/DBD/Function.pm'
--- src/tools/DBD/Function.pm	2010-04-08 20:52:36 +0000
+++ src/tools/DBD/Function.pm	2012-08-21 19:21:19 +0000
@@ -3,8 +3,7 @@
 @ISA = qw(DBD::Base);
 
 sub init {
-    return shift->SUPER::init(shift, "function name");
+    return shift->SUPER::init(shift, "function");
 }
 
 1;
-

=== modified file 'src/tools/DBD/Menu.pm'
--- src/tools/DBD/Menu.pm	2012-06-27 16:58:23 +0000
+++ src/tools/DBD/Menu.pm	2012-08-21 17:24:46 +0000
@@ -4,7 +4,7 @@
 
 sub init {
     my ($this, $name) = @_;
-    $this->SUPER::init($name, "menu name");
+    $this->SUPER::init($name, "menu");
     $this->{CHOICE_LIST} = [];
     $this->{CHOICE_INDEX} = {};
     return $this;
@@ -39,6 +39,13 @@
     return exists $this->{CHOICE_INDEX}->{$value};
 }
 
+sub equals {
+    my ($a, $b) = @_;
+    return $a->SUPER::equals($b)
+        && join(',', map "$_->[0]:$_->[1]", @{$a->{CHOICE_LIST}})
+        eq join(',', map "$_->[0]:$_->[1]", @{$b->{CHOICE_LIST}});
+}
+
 sub toDeclaration {
     my $this = shift;
     my $name = $this->name;

=== modified file 'src/tools/DBD/Recfield.pm'
--- src/tools/DBD/Recfield.pm	2010-04-14 20:16:36 +0000
+++ src/tools/DBD/Recfield.pm	2012-08-21 22:43:10 +0000
@@ -49,7 +49,7 @@
 sub init {
     my ($this, $name, $type) = @_;
     unquote $type;
-    $this->SUPER::init($name, "record field name");
+    $this->SUPER::init($name, "record field");
     dieContext("Illegal field type '$type', valid field types are:",
         sort keys %field_types) unless exists $field_types{$type};
     $this->{DBF_TYPE} = $type;
@@ -91,6 +91,10 @@
     return $this->attributes->{$attr};
 }
 
+sub equals {
+    dieContext("Record field objects are not comparable");
+}
+
 sub check_valid {
     my ($this) = @_;
     my $name = $this->name;

=== modified file 'src/tools/DBD/Recordtype.pm'
--- src/tools/DBD/Recordtype.pm	2010-04-08 22:09:59 +0000
+++ src/tools/DBD/Recordtype.pm	2012-08-22 19:33:06 +0000
@@ -5,8 +5,8 @@
 use Carp;
 
 sub init {
-    my $this = shift;
-    $this->SUPER::init(@_);
+    my ($this, $name) = @_;
+    $this->SUPER::init($name, "record type");
     $this->{FIELD_LIST} = [];
     $this->{FIELD_INDEX} = {};
     $this->{DEVICE_LIST} = [];
@@ -50,14 +50,15 @@
     confess "Not a DBD::Device" unless $device->isa('DBD::Device');
     my $choice = $device->choice;
     if (exists $this->{DEVICE_INDEX}->{$choice}) {
-        my @warning = ("Duplicate device type '$choice'");
+        return if $device->equals($this->{DEVICE_INDEX}->{$choice});
+        my $rnam = $this->{NAME};
+        my @warning = ("Two $rnam device supports '$choice' conflict");
         my $old = $this->{DEVICE_INDEX}->{$choice};
         push @warning, "Link types differ"
             if ($old->link_type ne $device->link_type);
         push @warning, "DSETs differ"
             if ($old->name ne $device->name);
-        warnContext(@warning);
-        return;
+        dieContext(@warning);
     }
     push @{$this->{DEVICE_LIST}}, $device;
     $this->{DEVICE_INDEX}->{$choice} = $device;
@@ -85,6 +86,11 @@
     return join("\n", shift->cdefs) . "\n\n";
 }
 
+sub equals {
+    my ($a, $b) = @_;
+    dieContext("Duplicate definition of record type '$a->{NAME}'");
+}
+
 sub toDeclaration {
     my $this = shift;
     my @fields = map {

=== modified file 'src/tools/DBD/Registrar.pm'
--- src/tools/DBD/Registrar.pm	2010-04-08 20:52:36 +0000
+++ src/tools/DBD/Registrar.pm	2012-08-21 19:21:26 +0000
@@ -3,9 +3,7 @@
 @ISA = qw(DBD::Base);
 
 sub init {
-    return shift->SUPER::init(shift, "registrar function name");
+    return shift->SUPER::init(shift, "registrar function");
 }
 
-
 1;
-

=== modified file 'src/tools/DBD/Variable.pm'
--- src/tools/DBD/Variable.pm	2012-03-27 15:47:59 +0000
+++ src/tools/DBD/Variable.pm	2012-08-21 17:00:00 +0000
@@ -18,7 +18,7 @@
     exists $valid_types{$type} or
         dieContext("Unknown variable type '$type', valid types are:",
             sort keys %valid_types);
-    $this->SUPER::init($name, "variable name");
+    $this->SUPER::init($name, "variable");
     $this->{VAR_TYPE} = $type;
     return $this;
 }
@@ -33,4 +33,10 @@
     return $valid_types{$this->{VAR_TYPE}};
 }
 
+sub equals {
+    my ($a, $b) = @_;
+    return $a->SUPER::equals($b)
+        && $a->{VAR_TYPE} eq $b->{VAR_TYPE};
+}
+
 1;