short-circuit let

Library for writing more flexible let forms, which may exit earlier with a custom value.

Install

Add the following dependency into your deps.edn file:

io.github.filipencopav/short-circuit {:git/sha "11b4d95"
                                      :git/tag "v1.1"}

Usage

Require it:

(require '[filipencopav.short-circuit :as sc])

• sc/let: Use it to create a let binding that can short-circuit when a certain value is bound.
• sc/exit: Use it to mark a value as a short-circuiting one. sc/let will return the value.

Examples

When all goes well, functions as normal let

(require 'filipencopav.short-circuit :as sc)

(def m {:key1 1})

(sc/let [a (:key1 m)
         b (if a
             (+ a 5)
             (sc/exit {:error "provided map doesn't have :key1"}))]
  (+ a b)) ;=> 7

When receives a value wrapped in sc/exit (it’s a reduced value under the hood), short-circuits and returns the value early.

(def m2 {})

;; same form as above
(sc/let [a (:key1 m2)
         b (if a
             (+ a 5)
             (sc/exit {:error "provided map doesn't have :key1"}))]
  (+ a b)) ;=> {:error "provided map doesn't have :key1"}

License

BSD 3 clause.