clj-ripple

clj-ripple is a library for translating Clojure source code into Ripple source code, which can then be executed. This allows for easy embedding of Ripple into Clojure programs.

Syntax

The ripple macro takes specially formatted Clojure source code and translates (using the translate function) it into the equivalent Ripple source code. It then executes it using the run-ripple function, inside an evironment created with the with-ripple macro, which dynamically binds the ripple variable to a fresh QueryPipe and the sink variable to a fresh Collector<T,E> sink.

Although all of those components (with-ripple, run-ripple & translate) can be used separately, it is best to simple use the ripple macro.

The result is return as a Clojure lazy sequence containing all the stacks as sequences. The topmost elements in the stacks appear first and are followed by the elements at the bottom. Example: ((top, top-1, top-2), (top, top-1), (top, top-1, top-2, ..., top-n))

Examples

clj-ripple syntax and its equivalent Ripple source code can be understood by reading the following examples:

@prefix foaf: http://xmlns.com/foaf/0.1/ @list dan: http://danbri.org/foaf.rdf#danbri :dan. foaf:knows. foaf:name. (ripple (prefix foaf "http://xmlns.com/foaf/0.1/") ; An string passed to prefix is inmediately put inside <> (def dan @"http://danbri.org/foaf.rdf#danbri") ; Since regular strings can be used as data, in non-prefix situations, strings must be dereferenced in order to be evaluated as URLs. (!/dan foaf/knows foaf/name) ; !/ is the default namespace. )

@list days: "Monday" "Tuesday" "Wednesday" "Thursday" "Friday" "Saturday" "Sunday" 1 2 3 :days. (ripple (def days "Monday" "Tuesday" "Wednesday" "Thursday" "Friday" "Saturday" "Sunday") (1 2 3 !/days) ; By default, lists and other primitives are applied the . (op) operator. )

@list days: "Monday" "Tuesday" "Wednesday" "Thursday" "Friday" "Saturday" "Sunday" 1 2 3 :days (ripple (def days "Monday" "Tuesday" "Wednesday" "Thursday" "Friday" "Saturday" "Sunday") (1 2 3 '!/days) ; But quoting them removes the . (op) operator. )

16 dup. mul. (ripple (16 dup mul) )

@list n triangle: n 1 add. n mul. 2 div. 4 :triangle. (ripple (def triangle [n] ; To created a parametered list, give it an args vector. n 1 add n mul 2 div) (4 !/triangle) )

@list fact: dup. 0 equal. (1 popd.) (dup. 1 sub. :fact. mul.) branch. 5 :fact. (ripple (def fact dup 0 equal (1 popd) (dup 1 sub !/fact mul) branch) (5 !/fact) )

Top level lists are evaluated as single lines of Ripple code. Different lines must be specified as different lists to avoid confusion Lists inside lists, however, are interpreted as Ripple lists.

@show prefixes @show contexts (ripple (show :prefixes) (show :contexts) )

(10 20 30) rdf:rest{2} rdf:first. (ripple ((10 20 30) [rdf/rest 2] rdf/first) )

(10 20 30) rdf:rest{0,1} rdf:first. (ripple ((10 20 30) [rdf/rest 0 1] rdf/first) )

For more information about Ripple, please visit the following websites:

• http://ripple.fortytwo.net/
• https://github.com/joshsh/ripple/wiki