Re: [DISCUSS] S-Type

[Marko Rodriguez]

BTW: Here is GroovyTranslator for Gremlin-Python.

https://gist.github.com/okram/406157b21371a540d2641f52a4208760 


Realize that Translator exists as a class in both Java and in Python with 
identical APIs. … and will exist as such in JavaScript, Ruby, etc.

Its really not that complicated to create a Translator. The complication exists 
in XXXTraversal, XXXTraversalSource, and XXXAnonymousTraversal:
https://gist.github.com/okram/fe6bdfe36b970af73b2bcb9e3cfc5e3d 

..but that is written once and used over and over by various translators. 
Moreover, that source code is generated automagically via introspection into 
the Gremlin-Java API.
https://gist.github.com/okram/88f0ddbd9d0d257d1113b0740260a6b6 


Marko.

http://markorodriguez.com



> On Jun 16, 2016, at 7:35 AM, Marko Rodriguez  wrote:
> 
> Hello,
> 
>> I think this is generally on the right track as there aren't many other
>> tracks to get this to work. Is it possible to leave open the option for a
>> language that is translating into itself (e.g. javascript to javascript) to
>> have the ability to take a non-string lambda if it is a language that is
>> capable of inspecting itself to get the string representation of its own
>> code?
> 
> Yes. So with Python we can inspect the lambda. Thus, if you are in CPython 
> and want to submit a Gremlin-Python traversal to GremlinServer running 
> Jython, then the PythonTranslator would NOT just evaluate the lambda for a 
> String, but instead would do the following — inspect the lambda for a String:
> 
> >>> from dill.source import getsource
> >>> x = lambda a: a + 2
> >>> x
>  at 0x10bfe70c8>
> >>> getsource(x)
> 'x = lambda a: a + 2\n'
> >>>
> 
> Realize that since we have decoupled the “translator” from the “language,” 
> anyone can use Gremlin-Python and write their own translator. That translator 
> can do as they please with each step(args). Thus, CPython->Jython can do as 
> above with lambdas and introspect to get the code string during translation. 
> For Gremlin-Python with GroovyTranslator, the best I have come up with is:
> 
> >>> g.V().out().map(lambda: "it.get().value('name')")
> g.V().out().map({it.get().value('name')})
> 
> Now, another drawback of “the best I have come up with" is that the 
> translator’s target language is showing up in the host language. That is, the 
> traversal above is forced to use a GroovyTranslator and thus is not portable 
> to any other translator. While, if a traversal did NOT have lambdas, you 
> could easily change the translator and everything would just work as expected.
> 
> Take care,
> Marko.
> 
> http://markorodriguez.com 
> 
> 
>> 
>> On Thu, Jun 16, 2016 at 2:12 AM, Daniel Kuppitz > > wrote:
>> 
>>> I wouldn't say that I like it, cause code as a String will always be very
>>> error prone, but still, it's likely the only way to get lambdas working in
>>> all language variants. Hence: "cool".
>>> 
>>> Cheers,
>>> Daniel
>>> 
>>> 
>>> On Thu, Jun 16, 2016 at 12:03 AM, Marko Rodriguez >> >
>>> wrote:
>>> 
 Hi,
 
 What do people think of this idea:
 
https://gist.github.com/okram/df6a104bde51a4f4f6f0da11f46909d5 
  <
 https://gist.github.com/okram/df6a104bde51a4f4f6f0da11f46909d5 
 >
 
 If you pass a lambda/closure/anonymousFunction/etc. in the respective
 language (during translation), it calls it to get the string
 representation. … ?
 
 Marko.
 
 http://markorodriguez.com 
 
 
 
> On Jun 15, 2016, at 10:50 AM, Marko Rodriguez 
 wrote:
> 
> Hello,
> 
> I think we should introduce an S object. It would stand for Script and
 would allow you to do:
> 
> S.f(“{ it.length }”)
> 
> Where does this come in handy? Language variants.
> 
> Imagine using gremlin_python that will compile to Gremlin-Groovy for
 execution at GremlinServer.
> 
>  g.V().out(“knows”)[0:2].name.map(f(“{ it.length }”))
> 
> Next, imagine you are in Gremlin-Java and want to submit a traversal to
 GremlinServer, but it has a lambda. No worries, just use the
 GroovyTranslator and you have:
> 
>  g.V().out(“knows”).limit(2).values(“name”).map(f(“{ it.length
>>> }”))
> 
> We could also have:
> 
>  S.s = supplier
>  S.c = consumer
>  S.f = function
>  S.o = operator
> 
> This gets to the general problem of being able to translate 

[DISCUSS] S-Type

[Marko Rodriguez]

Hello,

I think we should introduce an S object. It would stand for Script and would 
allow you to do:

S.f(“{ it.length }”)

Where does this come in handy? Language variants.

Imagine using gremlin_python that will compile to Gremlin-Groovy for execution 
at GremlinServer.

g.V().out(“knows”)[0:2].name.map(f(“{ it.length }”))

Next, imagine you are in Gremlin-Java and want to submit a traversal to 
GremlinServer, but it has a lambda. No worries, just use the GroovyTranslator 
and you have:

g.V().out(“knows”).limit(2).values(“name”).map(f(“{ it.length }”))

We could also have:

S.s = supplier
S.c = consumer
S.f = function
S.o = operator

This gets to the general problem of being able to translate lambdas between 
different languages as well as being able to send lambdas over the wire.

Thoughts?,
Marko.

http://markorodriguez.com