Add expand-query macro

[Gerrrr]

Implementation for https://github.com/nathanmarz/cascalog/issues/27

[sritchie]

Nice! Want to add an example expansion to the issue? Then we can move this over to the documentation. Awesome work.

[danoyoung]

This is great! An example would be awesome.

Regards,

Dano On Mar 8, 2014 10:26 AM, "Sam Ritchie" notifications@github.com wrote:

Nice! Want to add an example expansion to the issue? Then we can move this over to the documentation. Awesome work.

Reply to this email directly or view it on GitHubhttps://github.com/nathanmarz/cascalog/pull/237#issuecomment-37103620 .

[Gerrrr]

Thanks for the warm feedback.

Example with query taken from introduction tutorial:

user> (expand-query [?person ?a2] (age ?person ?age)
                    (< ?age 30) (* 2 ?age :> ?a2))
{:fields ["?person" "?a2"],
 :predicates
 ({:op
   [["alice" 28]
    ["bob" 33]
    ["chris" 40]
    ["david" 25]
    ["emily" 25]
    ["george" 31]
    ["gary" 28]
    ["kumar" 27]
    ["luanne" 36]],
   :input nil,
   :output ["?person" "?age"]}
  {:op #<core$_LT_ clojure.core$_LT_@55c0c66a>,
   :input ("?age" 30),
   :output []}
  {:op #<core$_STAR_ clojure.core$_STAR_@61415858>,
   :input (2 "?age"),
   :output ["?a2"]}),
 :options
 {:trap nil,
  :spill-threshold nil,
  :reverse nil,
  :sort nil,
  :distinct false,
  :reducers nil}}

[sritchie]

Awesome. I think if you use print vs pprint, these custom printers will take hold:

https://github.com/Gerrrr/cascalog/blob/feature/expand_query/cascalog-core/src/clj/cascalog/logic/predicate.clj#L48

And you'll see an expanded version of the query without the explicit op, input, output. I like the way this looks, though.

[Gerrrr]

So, now it looks like that:

user> (expand-query [?person ?a2] (age ?person ?age)
              (< ?age 30) (* 2 ?age :> ?a2))
(<- [?person ?a2]
    (#'cascalog.playground/age  :> ?person ?age)
    (#'clojure.core/< ?age 30)
    (#'clojure.core/* 2 ?age :> ?a2)
    )

[sorenmacbeth]

very nice!

On Sat, Mar 8, 2014 at 3:15 PM, Aleksandr Sorokoumov < notifications@github.com> wrote:

So, now it looks like that:

user> (expand-query [?person ?a2](age ?person ?age) (< ?age 30) (* 2 ?age :> ?a2)) (<- [?person ?a2](#'cascalog.playground/age :> ?person ?age) (#'clojure.core/< ?age 30) (#'clojure.core/* 2 ?age :> ?a2) )

Reply to this email directly or view it on GitHubhttps://github.com/nathanmarz/cascalog/pull/237#issuecomment-37113059 .

http://about.me/soren

[danoyoung]

Sweet! On Mar 8, 2014 4:15 PM, "Aleksandr Sorokoumov" notifications@github.com wrote:

So, now it looks like that:

user> (expand-query [?person ?a2](age ?person ?age) (< ?age 30) (* 2 ?age :> ?a2))(<- [?person ?a2](#'cascalog.playground/age :> ?person ?age) (#'clojure.core/< ?age 30) (#'clojure.core/* 2 ?age :> ?a2) )

Reply to this email directly or view it on GitHubhttps://github.com/nathanmarz/cascalog/pull/237#issuecomment-37113059 .

[sritchie]

It gets better when you start to include predicate macros and other sugary delicacies.

[sorenmacbeth]

LGTM