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Matthew Davidson 2023-01-04 16:18:10 +01:00
parent 475b2bea94
commit 2f1fa3cc3b
1 changed files with 13 additions and 12 deletions
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19
src/koans/25_threading_macros.clj
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@ -15,23 +15,23 @@
(meditations (meditations
"We can use thread first for more readable sequential operations" "We can use thread first for more readable sequential operations"
(= __ (= {:a 1}
(-> {} (-> {}
(assoc :a 1))) (assoc :a 1)))
"Consider also the case of strings" "Consider also the case of strings"
(= __ (= "Hello world, and moon, and stars"
(-> "Hello world" (-> "Hello world"
(str ", and moon") (str ", and moon")
(str ", and stars"))) (str ", and stars")))
"When a function has no arguments to partially apply, just reference it" "When a function has no arguments to partially apply, just reference it"
(= __ (= "String with a trailing space"
(-> "String with a trailing space " (-> "String with a trailing space "
clojure.string/trim)) clojure.string/trim))
"Most operations that take a scalar value as an argument can be threaded-first" "Most operations that take a scalar value as an argument can be threaded-first"
(= __ (= 6
(-> {} (-> {}
(assoc :a 1) (assoc :a 1)
(assoc :b 2) (assoc :b 2)
@ -41,18 +41,18 @@
(get-in [:c :e]))) (get-in [:c :e])))
"We can use functions we have written ourselves that follow this pattern" "We can use functions we have written ourselves that follow this pattern"
(= __ (= 1
(-> {} (-> {}
(assoc :a 1) (assoc :a 1)
(function-that-takes-a-map "hello" "there"))) (function-that-takes-a-map "hello" "there")))
"We can also thread last using ->>" "We can also thread last using ->>"
(= __ (= '(2 3 4)
(->> [1 2 3] (->> [1 2 3]
(map inc))) (map inc)))
"Most operations that take a collection can be threaded-last" "Most operations that take a collection can be threaded-last"
(= __ (= 12
(->> a-list (->> a-list
(map inc) (map inc)
(filter even?) (filter even?)
@ -60,7 +60,8 @@
(reduce +))) (reduce +)))
"We can use functions we have written ourselves that follow this pattern" "We can use functions we have written ourselves that follow this pattern"
(= __ (= [1 2 3]
(->> a-list-with-maps (->> a-list-with-maps
(function-that-takes-a-coll "hello" "there") (function-that-takes-a-coll "hello" "there")
(into [])))) (into [])
)))