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Last active Dec 14, 2015
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A get-indent function to get the amount of indention for the next line of clojure code, based on the previous line.
(def closing {\) \(
\} \{
\] \[})
(def opening [\( \{ \[])
(defn zero-or-more [x] (if (>= x 0) x 0))
(defn indent-exception? [[a b]] (not (and (= a \') (= b \())))
; warning: Very basic clojure language parsing. It does not handle strings.
(defn reverse-parse
([data] (reverse-parse data []))
([data starting-stack]
(loop [pos (dec (.length data))
stack starting-stack]
(if (< pos 0)
[pos stack]
(let [cur (.charAt data pos)]
(contains? closing cur) (recur (dec pos) (conj stack (closing cur)))
(= (peek stack) cur) (recur (dec pos) (pop stack))
(some {cur true} opening) [pos stack]
:else (recur (dec pos) stack)))))))
(defn get-indent [data]
(let [pos (first (reverse-parse data))]
(if (= pos -1)
(count (re-find #"^\s+" data)) ;match indent
(if (indent-exception? [(.charAt data (zero-or-more (dec pos))) (.charAt data pos)])
(let [m (re-matcher #"[,\s]+" (.substring data pos))]
(if (.find m)
(+ pos (.end m)) ;match first parameter position
(inc pos))))) ;match inside delimiter position
(get-indent "(defn thing [x]") ; => 6
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