Index: library/mongodb/example-nsf-mongo.tcl
===================================================================
diff -u -rbcf94f0b3bac771ebd9a65a8eb9dd6030651bb7e -r9248d253eb37bcefbfa38a1d86df306f40922444
--- library/mongodb/example-nsf-mongo.tcl	(.../example-nsf-mongo.tcl)	(revision bcf94f0b3bac771ebd9a65a8eb9dd6030651bb7e)
+++ library/mongodb/example-nsf-mongo.tcl	(.../example-nsf-mongo.tcl)	(revision 9248d253eb37bcefbfa38a1d86df306f40922444)
@@ -20,7 +20,7 @@
 						   classes array {0 object {$ref string courses $id oid 1}}]
   ::mongo::insert $mongoConn tutorial.persons [list name string Gustaf projects string nsf age int 53]
   ::mongo::insert $mongoConn tutorial.persons [list name string Stefan projects string nsf]
-  ::mongo::insert $mongoConn tutorial.persons [list name string Franz info object {x int 203 y int 102} age int 29]
+  ::mongo::insert $mongoConn tutorial.persons [list name string Franz info object {x int 203 y int 102} age int 29 projects string gtat]
   ::mongo::insert $mongoConn tutorial.persons [list name string Victor a array {0 string "x" 1 string "y"} age int 31]
   ::mongo::insert $mongoConn tutorial.persons [list name string Selim ts timestamp {1302945037 1} d date 1302947619279]
 
@@ -48,8 +48,11 @@
 puts  [join [::mongo::query $mongoConn tutorial.persons [list \$query object {a string "x"}]] \n]
 
 puts stderr "\nEmbedded object has some value (info.y > 100)"
-puts  [join [::mongo::query $mongoConn tutorial.persons [list \$query object {info.y object {$gt int 100}}]] \n]
+puts [join [::mongo::query $mongoConn tutorial.persons [list \$query object {info.y object {$gt int 100}}]] \n]
 
+puts stderr "\nProjects in {nsf gtat}"
+puts [join [::mongo::query $mongoConn tutorial.persons [list \$query object {projects object {$in array {0 string nsf 1 string gtat}}}]] \n]
+
 if {0} {
   puts stderr "\nDelete members of project abc"
   ::mongo::remove $mongoConn tutorial.persons [list projects string abc]
Index: library/mongodb/example-nx-mongo.tcl
===================================================================
diff -u -rc85ca5808548fc506bfc39600bafb8b11ecfac43 -r9248d253eb37bcefbfa38a1d86df306f40922444
--- library/mongodb/example-nx-mongo.tcl	(.../example-nx-mongo.tcl)	(revision c85ca5808548fc506bfc39600bafb8b11ecfac43)
+++ library/mongodb/example-nx-mongo.tcl	(.../example-nx-mongo.tcl)	(revision 9248d253eb37bcefbfa38a1d86df306f40922444)
@@ -28,14 +28,14 @@
 # Insert a tuple to the database via creating an object, saving and
 # destroying it:
 #
-set p [Person new -name Gustaf -projects nsf -age 53]
+set p [Person new -name Gustaf -projects {nsf nx nxmongo} -age 53]
 $p save; $p destroy
 
 #
 # The insert operation of above can be achieved with less typing via
 # the conveniance method "insert":
 #
-Person insert -name Stefan -projects nsf
+Person insert -name Stefan -projects {nsf nx}
 Person insert -name Joe -projects abc -age 23
 Person insert -name Franz -projects {gtat annobackend abc} -age 29
 
@@ -65,6 +65,17 @@
   puts "\t$p:\t[$p name]"
 }
 
+puts "\nProject members of nsf or gtat:"
+foreach p [Person find all -cond {projects in {nsf gtat}}] {
+  puts "\t$p:\t[$p name]"
+}
+
+puts "\nProject members on both nsf and nxmongo:"
+foreach p [Person find all -cond {projects all {nsf nxmongo}}] {
+  puts "\t$p:\t[$p name]"
+}
+
+
 puts "\nAll Persons sorted by name (ascending):"
 foreach p [Person find all -orderby name] {
   puts "\t$p:\t[$p name]"
Index: library/mongodb/example-nx-reference-many.tcl
===================================================================
diff -u -r8f4ba2af8b01697a3aab727a2794cb3b456d6632 -r9248d253eb37bcefbfa38a1d86df306f40922444
--- library/mongodb/example-nx-reference-many.tcl	(.../example-nx-reference-many.tcl)	(revision 8f4ba2af8b01697a3aab727a2794cb3b456d6632)
+++ library/mongodb/example-nx-reference-many.tcl	(.../example-nx-reference-many.tcl)	(revision 9248d253eb37bcefbfa38a1d86df306f40922444)
@@ -52,8 +52,8 @@
 # Retrieve the entry from the database:
 set g [Group find first -cond {name = "grp2"}]
 set members [list]
-foreach m [$g members] {
-  lappend members [Member find first -cond [list _id = $m]]
+foreach m [Member find all -cond [list _id in [$g members]]] {
+  lappend members $m
 }
 puts stderr "Members of group [$g name]:"
 foreach m $members {puts stderr "\t[$m name]"}
Index: library/mongodb/example-nx-reference-one.tcl
===================================================================
diff -u -r8f4ba2af8b01697a3aab727a2794cb3b456d6632 -r9248d253eb37bcefbfa38a1d86df306f40922444
--- library/mongodb/example-nx-reference-one.tcl	(.../example-nx-reference-one.tcl)	(revision 8f4ba2af8b01697a3aab727a2794cb3b456d6632)
+++ library/mongodb/example-nx-reference-one.tcl	(.../example-nx-reference-one.tcl)	(revision 9248d253eb37bcefbfa38a1d86df306f40922444)
@@ -1,8 +1,8 @@
 #
 # This is an introductory example how to use the nx mongo mapping for
 # referencing some object. We use here an example of an Posting having
-# a (possible compound) user as originator. All example work the same
-# way as well with with multivalued attributes.
+# a single (possible compound) user as originator. All example work
+# the same way as well with with multivalued attributes.
 #
 # Gustaf Neumann              fecit, May 2011
 #
Index: library/mongodb/nx-mongo.tcl
===================================================================
diff -u -rbcf94f0b3bac771ebd9a65a8eb9dd6030651bb7e -r9248d253eb37bcefbfa38a1d86df306f40922444
--- library/mongodb/nx-mongo.tcl	(.../nx-mongo.tcl)	(revision bcf94f0b3bac771ebd9a65a8eb9dd6030651bb7e)
+++ library/mongodb/nx-mongo.tcl	(.../nx-mongo.tcl)	(revision 9248d253eb37bcefbfa38a1d86df306f40922444)
@@ -131,12 +131,16 @@
       }
     }
 
-    :method "bson encode" {value} {
-      if {[:isMultivalued]} {
-	set c -1
-	set array [list]
-	foreach v $value {lappend array [incr c] {*}[:bson encodeValue $v]}
-	return [list array $array]
+    :method "bson encodeArray" {value} {
+      set c -1
+      set array [list]
+      foreach v $value {lappend array [incr c] {*}[:bson encodeValue $v]}
+      return [list array $array]
+    }
+
+    :public method "bson encode" {-array:switch value} {
+      if {[:isMultivalued] || $array} {
+	return [:bson encodeArray $value]
       } else {
 	return [:bson encodeValue $value]
       }
@@ -224,7 +228,7 @@
     }
     
     :public method "get relop" {op} {
-      array set "" {< $lt > $gt <= $lte >= $gte != $ne}
+      array set "" {< $lt > $gt <= $lte >= $gte != $ne in $in all $all}
       return $($op)
     }
     
@@ -245,6 +249,9 @@
 	">" - "<" - "<=" - ">=" - "!="  {
 	  lappend bson $att object [list [:get relop $op] [$slot mongotype] $value]
 	}
+	"in" - "all" {
+	  lappend bson $att object [list [:get relop $op] {*}[$slot bson encode -array $value]]
+	}
 	default {error "unknown operator $op"}
       }
       }
@@ -329,11 +336,11 @@
     #
     # index method
     #
-    :public method index {att {-type 1}} {
+    :public method index {att {-type 1} args} {
       if {![info exists :mongo_ns]} {:mongo_setup}
-      # todo: 2d index will need a different type
-      #::mongo::index $::mongoConn ${:mongo_ns} [list $att int $type]
-      db index ${:mongo_ns} [list $att int $type]
+      # todo: 2nd index will need a different type
+      # todo: multi-attribute indices
+      db index ${:mongo_ns} [list $att int $type] {*}$args
     }
     
     #