Merge lp:~zorba-coders/zorba/jsoniq-library-functions into lp:zorba

[Ghislain Fourny]

Adding missing JSONiq library functions.

Adding missing JSONiq library functions.

[Zorba Build Bot (zorba-buildbot)]

Validation queue starting for merge proposal.
Log at: http://zorbatest.lambda.nu:8080/remotequeue/jsoniq-library-functions-2012-08-13T13-33-00.38Z/log.html

[Zorba Build Bot (zorba-buildbot)]

The attempt to merge lp:~zorba-coders/zorba/jsoniq-library-functions into lp:zorba failed. Below is the output from the failed tests.

CMake Error at /home/ceej/zo/testing/zorbatest/tester/TarmacLander.cmake:274 (message):
  Validation queue job jsoniq-library-functions-2012-08-13T13-33-00.38Z is
  finished. The final status was:

  1 tests did not succeed - changes not commited.

Error in read script: /home/ceej/zo/testing/zorbatest/tester/TarmacLander.cmake

[Zorba Build Bot (zorba-buildbot)]

Validation queue starting for merge proposal.
Log at: http://zorbatest.lambda.nu:8080/remotequeue/jsoniq-library-functions-2012-08-14T13-16-06.204Z/log.html

[Zorba Build Bot (zorba-buildbot)]

Validation queue job jsoniq-library-functions-2012-08-14T13-16-06.204Z is finished. The final status was:

All tests succeeded!

[Zorba Build Bot (zorba-buildbot)]

Voting does not meet specified criteria. Required: Approve > 1, Disapprove < 1, Needs Fixing < 1, Pending < 1. Got: 2 Pending.

[Till Westmann (tillw)]

Looks good and works for me.

review: Approve

[Zorba Build Bot (zorba-buildbot)]

There are additional revisions which have not been approved in review. Please seek review and approval of these new revisions.

[Zorba Build Bot (zorba-buildbot)]

Validation queue starting for merge proposal.
Log at: http://zorbatest.lambda.nu:8080/remotequeue/jsoniq-library-functions-2012-08-15T14-11-15.358Z/log.html

[Zorba Build Bot (zorba-buildbot)]

Validation queue job jsoniq-library-functions-2012-08-15T14-11-15.358Z is finished. The final status was:

All tests succeeded!

[Zorba Build Bot (zorba-buildbot)]

Voting does not meet specified criteria. Required: Approve > 1, Disapprove < 1, Needs Fixing < 1, Pending < 1. Got: 1 Approve, 2 Pending.

[Matthias Brantner (matthias-brantner)]

In functions.xq, the error jerr:JNDY0003 raised by jn:error should be documented explicitly using xqdoc's @error tag.

I'm not sure I like the name (function-library) of the new module but I don't have any better suggestions.

review: Needs Fixing

[Ghislain Fourny (gislenius)]

Hi Matthias,

Thanks! I added the @error tag.

[Zorba Build Bot (zorba-buildbot)]

Validation queue starting for merge proposal.
Log at: http://zorbatest.lambda.nu:8080/remotequeue/jsoniq-library-functions-2012-08-30T14-13-07.942Z/log.html

[Zorba Build Bot (zorba-buildbot)]

Validation queue job jsoniq-library-functions-2012-08-30T14-13-07.942Z is finished. The final status was:

All tests succeeded!

[Zorba Build Bot (zorba-buildbot)]

Voting does not meet specified criteria. Required: Approve > 1, Disapprove < 1, Needs Fixing < 1, Pending < 1. Got: 1 Approve, 1 Needs Fixing, 1 Pending.

[Chris Hillery (ceejatec)]

I still think the definitions of some of these functions are weird, but this proposal does match the spec as it stands at the moment.

review: Approve

[Matthias Brantner (matthias-brantner)]

Ghislain, could you please add the new module to the ChangeLog?

review: Needs Fixing

[lp:~zorba-coders/zorba/jsoniq-library-functions]

10988. By Ghislain Fourny on 2012-09-03

Updated ChangeLog.

[Ghislain Fourny (gislenius)]

Hi Matthias, this is done.

[Matthias Brantner (matthias-brantner)]

review: Approve

[lp:~zorba-coders/zorba/jsoniq-library-functions]

10989. By Ghislain Fourny on 2012-09-05

Merged trunk back.

=== modified file 'ChangeLog'
--- ChangeLog	2012-08-31 15:21:31 +0000
+++ ChangeLog	2012-09-05 12:26:31 +0000
@@ -6,6 +6,8 @@
   * Allow prolog variables to be referenced before they are declared (XQuery 3.0 feature)
   * xml:parse (fragment parsing) now allows for a DOCTYPE declaration at the 
     beginning of the XML document (requested in bug #1016606).
+  * New module http://www.jsoniq.org/modules/function-library with handy JSONiq functions. jn:object is
+    also supported.
 
 Optimizations:
   * New memory management for compiler expressions (no more ref counting)

=== modified file 'modules/org/jsoniq/www/CMakeLists.txt'
--- modules/org/jsoniq/www/CMakeLists.txt	2012-01-31 01:00:55 +0000
+++ modules/org/jsoniq/www/CMakeLists.txt	2012-09-05 12:26:31 +0000
@@ -15,6 +15,8 @@
 IF(ZORBA_WITH_JSON)
   DECLARE_ZORBA_MODULE(FILE functions.xq VERSION 1.0
     URI "http://www.jsoniq.org/functions")
+  DECLARE_ZORBA_MODULE(FILE function-library.xq VERSION 1.0
+    URI "http://www.jsoniq.org/function-library")
   DECLARE_ZORBA_MODULE (FILE pregenerated/errors.xq
     URI "http://www.jsoniq.org/errors")
 ENDIF(ZORBA_WITH_JSON)

=== added file 'modules/org/jsoniq/www/function-library.xq'
--- modules/org/jsoniq/www/function-library.xq	1970-01-01 00:00:00 +0000
+++ modules/org/jsoniq/www/function-library.xq	2012-09-05 12:26:31 +0000
@@ -0,0 +1,174 @@
+xquery version "1.0";
+
+(:
+ : Copyright 2006-2012 The FLWOR Foundation.
+ :
+ : Licensed under the Apache License, Version 2.0 (the "License");
+ : you may not use this file except in compliance with the License.
+ : You may obtain a copy of the License at
+ :
+ : http://www.apache.org/licenses/LICENSE-2.0
+ :
+ : Unless required by applicable law or agreed to in writing, software
+ : distributed under the License is distributed on an "AS IS" BASIS,
+ : WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ : See the License for the specific language governing permissions and
+ : limitations under the License.
+:)
+
+
+(:~
+ : This module provides the functions defined by the JSONiq specification,
+ : chapter 8 (Function Library). JSONiq extends
+ : the XQuery specification to also deal with JSON data natively. See
+ :
+ :     http://www.jsoniq.org/
+ :
+ : for details.
+ :
+ : This module depends on having the JSONiq feature enabled in Zorba,
+ : i.e., Zorba must be compiled with ZORBA_WITH_JSON.
+ :
+ : @author Ghislain Fourny
+ :)
+module namespace libjn = "http://www.jsoniq.org/function-library";
+
+import module namespace jn = "http://www.jsoniq.org/functions";
+
+declare namespace ver = "http://www.zorba-xquery.com/options/versioning";
+declare option ver:module-version "1.0";
+
+(:~
+ : This function dynamically builds an object, like jn:object, except that
+ : it does not throw an error upon pair collision. Instead, it aggregates them
+ : into an array.
+ :
+ : @param $o A sequence of objects.
+ : @return The accumulated object.
+ :)
+declare function libjn:accumulate($o as object()*) as object()
+{
+  {[ $o ]}
+};
+
+(:~
+ : This function returns all Objects contained within a JSON item, regardless of
+ : depth.
+ :
+ : @param $i A JSON item.
+ : @return Its descendant objects.
+ :)
+declare function libjn:descendant-objects($i as json-item()) as object()*
+{
+  if ($i instance of object())
+  then
+    (
+      $i,
+      for $v in libjn:values($i)
+      where $v instance of json-item()
+      return libjn:descendant-objects($v)
+    )
+  else if ($i instance of array())
+  then
+    (
+      for $v in libjn:members($i)
+      where $v instance of json-item()
+      return libjn:descendant-objects($v)
+    )
+  else
+    ()
+};
+
+(:~
+ : This function returns all pairs contained within an object, recursively.
+ :
+ : @param $o An object.
+ : @return All direct and indirect descendant pairs.
+ :)
+declare function libjn:descendant-pairs($o as object()) as object()*
+{
+  for $k in jn:keys($o)
+  return (
+    { $k : $o($k) },
+    if ($o($k) instance of object())
+    then
+      libjn:descendant-pairs($o($k))
+    else ()
+  )
+};
+
+(:~
+ : Recursively "flatten" a JSON Array, by replacing any arrays with their
+ : members. Equivalent to
+ :
+ :   define function jn:flatten($arg as array()) {
+ :     for $value in jn:values($arg)
+ :     return
+ :       if ($value instance of array())
+ :       then jn:flatten($value)
+ :       else $value
+ :   };
+ :
+ : @param $a A JSON Array.
+ : @return The flattened version of $a.
+ :)
+declare function libjn:flatten($a as array()) as item()*
+{
+  jn:flatten($a)
+};
+
+(:~ This function returns the intersection of two objects, and aggregates
+ : values corresponding to the same name into an array.
+ :
+ : @param $o A sequence of objects.
+ : @return Their insersection.
+ :)
+declare function libjn:intersect($o as object()*) as object()
+{
+  {|
+    let $common-keys := jn:keys($o[1])[ every $object in $o[position() > 1]
+                                           satisfies jn:keys($object) = . ]
+    for $key in $common-keys
+    let $values := $o($key)
+    return
+      if (count($values) eq 1)
+      then { $key : $values }
+      else { $key : [ $values ] }
+  |}
+};
+
+(:~
+ : Returns the members of an Array.
+ :
+ : @param $a A JSON Array.
+ : @return The members of the specified array.
+ :)
+declare function libjn:members($o as array()) as item()*
+{
+  jn:members($o)
+};
+
+(:~
+ : Creates an object from the specified pairs of another given object. 
+ : Specifically, for each name in $names, if the object $o has a pair with
+ : that name, then a copy of that pair is included in the new object.
+ :
+ : @param $o A JSON Object.
+ : @param $names The names of the pairs to copy out of $o and insert into the new object
+ : @return The new object.
+ :)
+declare function libjn:project($o as object(), $names as xs:string*) as object()
+{
+  jn:project($o, $names)
+};
+
+(:~
+ : This functions returns all values in an Object.
+ : @param $i An object.
+ : @return Its values.
+ :)
+declare function libjn:values($i as object()) as item()*
+{
+  for $k in jn:keys($i)
+  return $i($k)
+};
\ No newline at end of file

=== modified file 'modules/org/jsoniq/www/functions.xq'
--- modules/org/jsoniq/www/functions.xq	2012-08-30 13:45:43 +0000
+++ modules/org/jsoniq/www/functions.xq	2012-09-05 12:26:31 +0000
@@ -135,3 +135,18 @@
  :)
 declare function jn:flatten($a as array()) as item()* external;
 
+(:~
+ : This function allows dynamic object construction by merging all
+ : its object parameters into a single object with a so-called "simple
+ : object union". A simple object union creates a new object, the pairs
+ : property of which is obtained by accumulating the pairs of all operand
+ : objects. An error jerr:JNDY0003 is raised if two pairs with the same
+ : name are encountered.
+ :
+ : @param $o A sequence of objects.
+ :
+ : @return The simple object union.
+ :
+ : @error jerr:JNDY0003 if there is a pair collision.
+ :)
+declare function jn:object($o as object()*) as object() external;

=== modified file 'src/context/static_context.cpp'
--- src/context/static_context.cpp	2012-08-30 13:45:43 +0000
+++ src/context/static_context.cpp	2012-09-05 12:26:31 +0000
@@ -538,6 +538,9 @@
 #ifndef ZORBA_NO_FULL_TEXT
             ns == ZORBA_FULL_TEXT_FN_NS ||
 #endif /* ZORBA_NO_FULL_TEXT */
+#ifndef ZORBA_WITH_JSON
+            ns == JSONIQ_FN_NS ||
+#endif /* ZORBA_WITH_JSON */
             ns == ZORBA_XML_FN_NS);
   }
   else if (ns == W3C_FN_NS || ns == XQUERY_MATH_FN_NS)

=== modified file 'src/functions/func_jsoniq_functions_impl.cpp'
--- src/functions/func_jsoniq_functions_impl.cpp	2012-08-30 13:45:43 +0000
+++ src/functions/func_jsoniq_functions_impl.cpp	2012-09-05 12:26:31 +0000
@@ -18,6 +18,7 @@
 #include "functions/func_jsoniq_functions.h"
 #include "functions/func_jsoniq_functions_impl.h"
 
+#include "runtime/json/json_constructors.h"
 #include "runtime/json/jsoniq_functions.h"
 #include "runtime/json/jsoniq_functions_impl.h"
 #include "runtime/core/item_iterator.h"
@@ -149,6 +150,20 @@
 }
 
 
+/*******************************************************************************
+
+********************************************************************************/
+PlanIter_t jn_object::codegen(
+  CompilerCB*,
+  static_context* sctx,
+  const QueryLoc& loc,
+  std::vector<PlanIter_t>& argv,
+  expr& ann) const
+{
+ return new JSONObjectIterator(sctx, loc, argv, true, false);
+}
+
+
 void populate_context_jsoniq_functions_impl(static_context* sctx)
 {
   DECL(sctx, op_zorba_object_insert,
@@ -158,6 +173,13 @@
          GENV_TYPESYSTEM.JSON_OBJECT_TYPE_ONE,
          true,
          GENV_TYPESYSTEM.EMPTY_TYPE));
+
+  DECL(sctx, jn_object,
+        (createQName("http://www.jsoniq.org/functions",
+                     "",
+                     "object"),
+         GENV_TYPESYSTEM.JSON_OBJECT_TYPE_STAR,
+         GENV_TYPESYSTEM.JSON_OBJECT_TYPE_ONE));
 }
 
 

=== modified file 'src/functions/func_jsoniq_functions_impl.h'
--- src/functions/func_jsoniq_functions_impl.h	2012-08-30 13:45:43 +0000
+++ src/functions/func_jsoniq_functions_impl.h	2012-09-05 12:26:31 +0000
@@ -57,6 +57,20 @@
 };
 
 
+class jn_object : public function
+{
+public:
+  jn_object(const signature& sig)
+    :
+  function(sig, FunctionConsts::JN_OBJECT_1)
+  {
+  }
+
+  bool mustCopyInputNodes(expr* fo, csize producer) const { return true; }
+
+  CODEGEN_DECL();
+};
+
 
 #endif // ZORBA_WITH_JSON
 

=== modified file 'src/functions/function_consts.h'
--- src/functions/function_consts.h	2012-08-30 13:45:43 +0000
+++ src/functions/function_consts.h	2012-09-05 12:26:31 +0000
@@ -230,6 +230,7 @@
 
 #ifdef ZORBA_WITH_JSON
   OP_OBJECT_INSERT_N,
+  JN_OBJECT_1,
 #endif
 
 #ifndef ZORBA_NO_FULL_TEXT

=== removed directory 'src/runtime/spec/json.moved'
=== added file 'test/rbkt/ExpQueryResults/zorba/jsoniq/jn_accumulate.xml.res'
--- test/rbkt/ExpQueryResults/zorba/jsoniq/jn_accumulate.xml.res	1970-01-01 00:00:00 +0000
+++ test/rbkt/ExpQueryResults/zorba/jsoniq/jn_accumulate.xml.res	2012-09-05 12:26:31 +0000
@@ -0,0 +1,1 @@
+{ "n1" : { "JSONiq XDM node" : "<node>10</node>" }, "n2" : { "JSONiq XDM node" : "<node>20</node>" } }

=== added file 'test/rbkt/ExpQueryResults/zorba/jsoniq/jn_descendant_objects.xml.res'
--- test/rbkt/ExpQueryResults/zorba/jsoniq/jn_descendant_objects.xml.res	1970-01-01 00:00:00 +0000
+++ test/rbkt/ExpQueryResults/zorba/jsoniq/jn_descendant_objects.xml.res	2012-09-05 12:26:31 +0000
@@ -0,0 +1,1 @@
+{ "foo" : "bar", "bar" : { "foo" : [ 1 ] }, "foobar" : "foo" }{ "foo" : [ 1 ] }

=== added file 'test/rbkt/ExpQueryResults/zorba/jsoniq/jn_descendant_pairs.xml.res'
--- test/rbkt/ExpQueryResults/zorba/jsoniq/jn_descendant_pairs.xml.res	1970-01-01 00:00:00 +0000
+++ test/rbkt/ExpQueryResults/zorba/jsoniq/jn_descendant_pairs.xml.res	2012-09-05 12:26:31 +0000
@@ -0,0 +1,1 @@
+{ "foo" : "bar" }{ "bar" : { "foo" : [ 1 ] } }{ "foo" : [ 1 ] }{ "foobar" : "foo" }
\ No newline at end of file

=== added file 'test/rbkt/ExpQueryResults/zorba/jsoniq/jn_intersect.xml.res'
--- test/rbkt/ExpQueryResults/zorba/jsoniq/jn_intersect.xml.res	1970-01-01 00:00:00 +0000
+++ test/rbkt/ExpQueryResults/zorba/jsoniq/jn_intersect.xml.res	2012-09-05 12:26:31 +0000
@@ -0,0 +1,1 @@
+{ "bar" : [ { "foo" : [ 1 ] }, { "bar" : [ 2 ] }, [ "this" ] ] }
\ No newline at end of file

=== added file 'test/rbkt/ExpQueryResults/zorba/jsoniq/jn_values.xml.res'
--- test/rbkt/ExpQueryResults/zorba/jsoniq/jn_values.xml.res	1970-01-01 00:00:00 +0000
+++ test/rbkt/ExpQueryResults/zorba/jsoniq/jn_values.xml.res	2012-09-05 12:26:31 +0000
@@ -0,0 +1,1 @@
+bar{ "foo" : [ 1 ] } foo

=== added file 'test/rbkt/ExpQueryResults/zorba/jsoniq/object_03.xml.res'
--- test/rbkt/ExpQueryResults/zorba/jsoniq/object_03.xml.res	1970-01-01 00:00:00 +0000
+++ test/rbkt/ExpQueryResults/zorba/jsoniq/object_03.xml.res	2012-09-05 12:26:31 +0000
@@ -0,0 +1,1 @@
+{ "toaster" : 200, "blender" : 250, "shirt" : 10, "socks" : 510, "broiler" : 20 }

=== added file 'test/rbkt/Queries/zorba/jsoniq/jn_accumulate.spec'
--- test/rbkt/Queries/zorba/jsoniq/jn_accumulate.spec	1970-01-01 00:00:00 +0000
+++ test/rbkt/Queries/zorba/jsoniq/jn_accumulate.spec	2012-09-05 12:26:31 +0000
@@ -0,0 +1,1 @@
+Serialization: method=json jsoniq-extensions=yes

=== added file 'test/rbkt/Queries/zorba/jsoniq/jn_accumulate.xq'
--- test/rbkt/Queries/zorba/jsoniq/jn_accumulate.xq	1970-01-01 00:00:00 +0000
+++ test/rbkt/Queries/zorba/jsoniq/jn_accumulate.xq	2012-09-05 12:26:31 +0000
@@ -0,0 +1,16 @@
+import module namespace libjn = "http://www.jsoniq.org/function-library";
+
+declare variable $xdoc :=
+<nodes>
+<node>10</node>
+<node>20</node>
+</nodes>;
+
+variable $obj :=  
+libjn:accumulate( 
+  for $node at $pos in $xdoc//node 
+  return { concat("n", $pos) : $node } 
+);
+
+$obj
+

=== added file 'test/rbkt/Queries/zorba/jsoniq/jn_descendant_objects.spec'
--- test/rbkt/Queries/zorba/jsoniq/jn_descendant_objects.spec	1970-01-01 00:00:00 +0000
+++ test/rbkt/Queries/zorba/jsoniq/jn_descendant_objects.spec	2012-09-05 12:26:31 +0000
@@ -0,0 +1,1 @@
+Serialization: method=json jsoniq-multiple-items=appended

=== added file 'test/rbkt/Queries/zorba/jsoniq/jn_descendant_objects.xq'
--- test/rbkt/Queries/zorba/jsoniq/jn_descendant_objects.xq	1970-01-01 00:00:00 +0000
+++ test/rbkt/Queries/zorba/jsoniq/jn_descendant_objects.xq	2012-09-05 12:26:31 +0000
@@ -0,0 +1,10 @@
+import module namespace libjn = "http://www.jsoniq.org/function-library";
+
+let $object :=
+{
+ "foo" : "bar",
+ "bar" : { "foo" : [1] },
+ "foobar" : "foo" 
+}
+return libjn:descendant-objects($object)
+

=== added file 'test/rbkt/Queries/zorba/jsoniq/jn_descendant_pairs.spec'
--- test/rbkt/Queries/zorba/jsoniq/jn_descendant_pairs.spec	1970-01-01 00:00:00 +0000
+++ test/rbkt/Queries/zorba/jsoniq/jn_descendant_pairs.spec	2012-09-05 12:26:31 +0000
@@ -0,0 +1,1 @@
+Serialization: method=json jsoniq-multiple-items=appended

=== added file 'test/rbkt/Queries/zorba/jsoniq/jn_descendant_pairs.xq'
--- test/rbkt/Queries/zorba/jsoniq/jn_descendant_pairs.xq	1970-01-01 00:00:00 +0000
+++ test/rbkt/Queries/zorba/jsoniq/jn_descendant_pairs.xq	2012-09-05 12:26:31 +0000
@@ -0,0 +1,10 @@
+import module namespace libjn = "http://www.jsoniq.org/function-library";
+
+let $object :=
+{
+ "foo" : "bar",
+ "bar" : { "foo" : [1] },
+ "foobar" : "foo" 
+}
+return libjn:descendant-pairs($object)
+

=== added file 'test/rbkt/Queries/zorba/jsoniq/jn_intersect.xq'
--- test/rbkt/Queries/zorba/jsoniq/jn_intersect.xq	1970-01-01 00:00:00 +0000
+++ test/rbkt/Queries/zorba/jsoniq/jn_intersect.xq	2012-09-05 12:26:31 +0000
@@ -0,0 +1,20 @@
+import module namespace libjn = "http://www.jsoniq.org/function-library";
+
+let $object :=
+{
+ "foo" : "bar",
+ "bar" : { "foo" : [1] },
+ "foobar" : "foo" 
+}
+let $object2 :=
+{
+ "bar" : { "bar" : [2] },
+ "foobar" : "foo" 
+}
+let $object3 :=
+{
+ "foo" : "bar",
+ "bar" : [ "this" ]
+}
+return libjn:intersect(($object, $object2, $object3))
+

=== added file 'test/rbkt/Queries/zorba/jsoniq/jn_values.spec'
--- test/rbkt/Queries/zorba/jsoniq/jn_values.spec	1970-01-01 00:00:00 +0000
+++ test/rbkt/Queries/zorba/jsoniq/jn_values.spec	2012-09-05 12:26:31 +0000
@@ -0,0 +1,1 @@
+Serialization: jsoniq-allow-mixed-xdm-jdm=yes jsoniq-multiple-items=appended

=== added file 'test/rbkt/Queries/zorba/jsoniq/jn_values.xq'
--- test/rbkt/Queries/zorba/jsoniq/jn_values.xq	1970-01-01 00:00:00 +0000
+++ test/rbkt/Queries/zorba/jsoniq/jn_values.xq	2012-09-05 12:26:31 +0000
@@ -0,0 +1,10 @@
+import module namespace libjn = "http://www.jsoniq.org/function-library";
+
+let $object :=
+{
+ "foo" : "bar",
+ "bar" : { "foo" : [1] },
+ "foobar" : "foo" 
+}
+return libjn:values($object)
+

=== added file 'test/rbkt/Queries/zorba/jsoniq/object_03.xq'
--- test/rbkt/Queries/zorba/jsoniq/object_03.xq	1970-01-01 00:00:00 +0000
+++ test/rbkt/Queries/zorba/jsoniq/object_03.xq	2012-09-05 12:26:31 +0000
@@ -0,0 +1,18 @@
+import module namespace jn = "http://www.jsoniq.org/functions";
+
+let $j := ({ "product" : "broiler", "store number" : 1, "quantity" : 20  },
+{ "product" : "toaster", "store number" : 2, "quantity" : 100 },
+{ "product" : "toaster", "store number" : 2, "quantity" : 50 },
+{ "product" : "toaster", "store number" : 3, "quantity" : 50 },
+{ "product" : "blender", "store number" : 3, "quantity" : 100 },
+{ "product" : "blender", "store number" : 3, "quantity" : 150 },
+{ "product" : "socks", "store number" : 1, "quantity" : 500 },
+{ "product" : "socks", "store number" : 2, "quantity" : 10 },
+{ "product" : "shirt", "store number" : 3, "quantity" : 10 })
+return
+jn:object(
+  for $sales in $j
+  let $pname := $sales("product")
+  group by $pname
+  return { $pname : sum(for $s in $sales return $s("quantity")) }
+)