From e935ccae82f72e37f32a7d1ccab254ca2b664620 Mon Sep 17 00:00:00 2001 From: Phil Hagelberg Date: Wed, 8 Dec 2010 22:52:57 -0800 Subject: [PATCH] subs should count backwards when given a negative argument. --- src/clj/clojure/core.clj | 11 ++++++++--- test/clojure/test_clojure/string.clj | 7 +++++++ 2 files changed, 15 insertions(+), 3 deletions(-) diff --git a/src/clj/clojure/core.clj b/src/clj/clojure/core.clj index 2664d0d..52261f4 100644 --- a/src/clj/clojure/core.clj +++ b/src/clj/clojure/core.clj @@ -4316,11 +4316,16 @@ (defn subs "Returns the substring of s beginning at start inclusive, and ending - at end (defaults to length of string), exclusive." + at end (defaults to length of string), exclusive. Negative offsets count + from the end of the string." {:added "1.0" :static true} - (^String [^String s start] (. s (substring start))) - (^String [^String s start end] (. s (substring start end)))) + (^String [^String s start] (subs s start (count s))) + (^String [^String s start end] + (let [count-back #(if (neg? %) + (+ (count s) %) + %)] + (.substring s (count-back start) (count-back end))))) (defn max-key "Returns the x for which (k x), a number, is greatest." diff --git a/test/clojure/test_clojure/string.clj b/test/clojure/test_clojure/string.clj index d6f6469..f08f847 100644 --- a/test/clojure/test_clojure/string.clj +++ b/test/clojure/test_clojure/string.clj @@ -118,3 +118,10 @@ (is (vector? result))) (is (= (list "foo") (s/split-lines "foo")))) +(deftest t-subs + (let [string "Nel mezzo del cammin di nostra vita."] + (is (= "del cammin di nostra vita." (subs string 10))) + (is (= "vita." (subs string -5))) + (is (= string (subs string 0))) + (is (= "di nostra vit" (subs string -15 -2))) + (is (= "Nel mezzo del cammin di nost" (subs string 0 -8))))) -- 1.7.1