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in core.logic by

This macro was somewhat useful when I was implementing static analysis for a compiler with core.logic.

(defmacro ==>> (link: expr-in & rel-forms)
"Thread the expr-in through rel-forms then unify with last rel-forms
(the 'out expression').


 (==>> (link: [1]) (firsto) (firsto) x))
 ;; 'x' will become bound to value 1

This macro expands to:
(fresh (link: _A _B)

 (firsto (link: [1])  _A)
 (firsto _A     _B)
 (==     _B     q))

If you imagine that the 'return value' of firsto is its last parameter,
then it works just like clojure.core/-> as return value of each form is
first argument of the following form."

3 Answers

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Comment made by: jasonjckn

There might be a better name, not sure.

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Comment made by: jasonjckn

renamed ==>> to ==->

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Reference: https://clojure.atlassian.net/browse/LOGIC-38 (reported by jasonjckn)