it-thread.adoc

Usage examples for tupelo.core/it→

Name: "it-thread" (literate threading macro)

Homepage: https://github.com/cloojure/tupelo

Lein coords: [tupelo "0.9.75"]

Usage: clojure

  (it-> ...)

Why?

Because every time you’ve wanted to:

(ns xyz
  (:use tupelo.core))
(it-> 3
  (let [x 9]
    (- x it))
  (inc it)
  (- it 6))
;=> 1

(it-> 42
      (if true
        (inc it)
        :blah)) ;=> 43
(it-> 42
      (if false
        (inc it)
        :blah)) ;=> :blah

; works same for `if-not`, `when`, `when-not`, etc.

(it-> 42
  (case 1
    1 (inc it)
    2 (dec it))) ;=> 43

(it-> 42
  (case 2
    1 (inc it)
    2 (dec it))) ;=> 41

(it-> 42
  (cond
    (= 1 2)
    (inc it))) ;=> 42

(it-> 42
  (cond
    (= 1 1)
    (dec it))) ;=> 41

(it-> 42
  (let [x 1]
    (+ it x))) ;=> 43

try

The current expression is threaded through the body of the try form. The same value is threaded through each catch clause and any finally clause.

(it-> 42
      (try
        (inc it)
        (catch Exception e
          (dec it))) ;=> 43

(it-> 42
      (try
        (+ it :foo)
        (catch Exception e
          (dec it)))) ;=> 41

(it-> 42
      (try
        (inc it)   ; warning: this result is lost
        (finally
          (+ 10 it)))) ;=> 52

; with anonymous functions
(it-> 7
      ((fn [x y] (* x y)) it 3))  ;=> 21
(it-> 42
      #(-> it inc inc)) ;=> 44