gistfile1.clj

(defn- lex-1
  "Lex one symbol from a string, and return the symbol and trailing source."
  [src clauses]
  (some
    (fn [[re action]]
      (let [matcher (re-matcher re src)]
        (if (.lookingAt matcher)
          [(if (fn? action) (action matcher) action)
           (.substring src (.end matcher))])))
    (partition 2 clauses)))
 
(defn- lex
  "Lex a string into tokens by matching against regexs and evaluating
  the matching associated function."
  [src & clauses]
  (loop [results []
         src src
         clauses clauses]
    (if-let [[result src] (lex-1 src clauses)]
      (let [results (conj results result)]
        (if (= src "")
          results
          (recur results src clauses))))))