I'm proposing the addition of a new types of map/list/set with specified
child types. There is no doubt about the need of a map which keys are
objects (like in groupCount()) and the benefits of using a g:Map over plain
json objects in GraphSON3.
> is that basically the core of the usability problem?
I think its a specification problem, not a usability problem.
GraphTraversal interface exposes valueMap() as a method that returns a
Map<String, E2>, but the GraphSON3 specification doesn't provide an
specification of a Map with string keys so it's being returned as an
Map<Object, Object>.
> Is there a way to do that? how do we know what's in the Map/List until we
iterate it all?
I think its a responsibility of the graph processor, that could optimize by
returning a specific type of traverser as a result of the execution of a
certain traversal (in the example, when the valueMap is the last step).
On Tue, Sep 19, 2017 at 6:56 PM, Stephen Mallette <spmalle...@gmail.com>
wrote:
> > user is stuck with a unspecified map, which contains strings as keys.
>
> so basically in .NET the result of valueMap() is stuck with "object" as a
> key when the user expects "string". i guess that's inconvenient. if you
> iterated the keys of the dictionary and wanted to do some string operation
> on that you'd have to cast - is that basically the core of the usability
> problem? i tend to think it's more inconvenient to not be able to get a
> proper result from groupCount() where the keys might be something other
> than a string - we definitely don't want to lose that capability.
>
> > tackle this at the source and try to specify the child types on
> serialization when we have that information.
>
> Is there a way to do that? how do we know what's in the Map/List until we
> iterate it all?
>
> On Tue, Sep 19, 2017 at 12:38 PM, Jorge Bay Gondra <
> jorgebaygon...@gmail.com
> > wrote:
>
> > I wanted to bump this open discussion that after the JIRA adjustments
> > probably got buried.
> >
> > On Tue, Sep 12, 2017 at 2:31 PM, Jorge Bay Gondra <
> > jorgebaygon...@gmail.com>
> > wrote:
> >
> > > Collections with unspecified child types are useful for mixed types,
> but
> > > we are reusing those types of collections for all the cases.
> > > This behaviour poses a problem for strict statically typed languages
> like
> > > C#. Let's see if I can explain myself with an example:
> > >
> > > valueMap() step yields a map representation. In GraphSON2, it was
> > returned
> > > as a js object (where keys are always strings), that were mapped to C#
> > > Dictionary<string, object> (equivalent of java's Map<String, Object>).
> > > In GraphSON3, it's returned as a "g:Map", that is mapped to C#
> > > Dictionary<object, object>. As there is no type coercion (ie: type
> > erasure
> > > in java) for Dictionary<string, object> to Dictionary<object, object>,
> > the
> > > user is stuck with a unspecified map, which contains strings as keys.
> > >
> > > This causes a problem in any statically typed languages (outside java
> > > generics w/ type-erasure thingy).
> > >
> > > There are workarounds (like exposing conversion methods or lazy
> > > deserialization) but maybe we can tackle this at the source and try to
> > > specify the child types on serialization when we have that information.
> > >
> > > On Mon, Sep 11, 2017 at 6:04 PM, Stephen Mallette <
> spmalle...@gmail.com>
> > > wrote:
> > >
> > >> Mixed types would be the problem - that's why objects within the
> > List/Map
> > >> have types embedded within them.
> > >>
> > >> On Mon, Sep 11, 2017 at 12:01 PM, Robert Dale <robd...@gmail.com>
> > wrote:
> > >>
> > >> > I'm not sure that's feasible since any list or map could contain
> mixed
> > >> > types. Maybe I don't understand the use case.
> > >> >
> > >> > Robert Dale
> > >> >
> > >> > On Mon, Sep 11, 2017 at 11:27 AM, Jorge Bay Gondra <
> > >> > jorgebaygon...@gmail.com
> > >> > > wrote:
> > >> >
> > >> > > Hi,
> > >> > > The new GraphSON3 g:List, g:Set and g:Map definitions are an
> > >> improvement
> > >> > > over js arrays and associative arrays, but they doesn't provide
> the
> > >> child
> > >> > > type information.
> > >> > >
> > >> > > We could add support for chid type info, something like
> > >> > > "g:List<g:Traverser>" or "g:Map<g:Int32,g:Vertex>".
> > >> > >
> > >> > > For typed languages, it would allow compile time checks.
> > >> > > For any technology, it would more user-friendly error messages
> > >> ("Expected
> > >> > > Vertex, obtained...").
> > >> > >
> > >> > > Jorge
> > >> > >
> > >> >
> > >>
> > >
> > >
> >
>
