On Thu, Jul 2, 2009 at 1:59 PM, Stuart
Halloway<[email protected]> wrote:
>
> Hi Mark,
>
> The balanced-test would be a great place to use "are" instead of "is".
Excellent suggestion! The new version of that function follows:
(deftest balanced-test
(are [text result]
(= (balanced? text) result)
"()" true
"[]" true
"([])" true
"[()]" true
"[]()" true
"[][[([])]]" true
"(" false
")" false
"[" false
"]" false
"][" false
")(" false
"( )" false
"([)" false
"[)]" false
"([)]" false
"({})" false
"[())]") false)
>> There is a challenge on the blog of Tony Morris at
>> http://dibblego.wordpress.com/2008/09/05/haskell-scala-java-7-functional-java-java/#comment-2460
>> .
>> It's a parsing problem for which he compares solutions in Haskell,
>> Scala and Java. I added a Clojure solution. I don't know if this is
>> the "best" way to solve this with Clojure, but it certainly works.
>> Here's my code, including unit tests.
>>
>> (use 'clojure.test)
>>
>> (defn- match [prev-char next-char]
>> (condp = prev-char
>> \( (= next-char \))
>> \[ (= next-char \])
>> false))
>>
>> ; Need a better name for this function.
>> (defn- helper [s stack]
>> (if (empty? s)
>> (empty? stack)
>> (let [c (first s)
>> top (first stack)
>> stack (if (match top c) (next stack) (cons c stack))]
>> (helper (next s) stack))))
>>
>> (defn balanced? [s] (helper s '()))
>>
>> (doseq [arg *command-line-args*]
>> (println (balanced? arg)))
>>
>> (deftest match-test
>> (is (match \( \)))
>> (is (match \[ \]))
>> (is (not (match \( \{))))
>>
>> (deftest balanced-test
>> (is (balanced? "()"))
>> (is (balanced? "[]"))
>> (is (balanced? "([])"))
>> (is (balanced? "[()]"))
>> (is (balanced? "[]()"))
>> (is (balanced? "[][[([])]]"))
>> (is (not (balanced? "(")))
>> (is (not (balanced? ")")))
>> (is (not (balanced? "[")))
>> (is (not (balanced? "]")))
>> (is (not (balanced? "][")))
>> (is (not (balanced? ")(")))
>> (is (not (balanced? "( )")))
>> (is (not (balanced? "([)")))
>> (is (not (balanced? "[)]")))
>> (is (not (balanced? "([)]")))
>> (is (not (balanced? "({})")))
>> (is (not (balanced? "[())]"))))
>>
>> (run-tests)
>>
>> --
>> R. Mark Volkmann
>> Object Computing, Inc.
>>
>> >
>
>
> >
>
--
R. Mark Volkmann
Object Computing, Inc.
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